CN118074310A - Substation power supply system - Google Patents

Abstract

The invention discloses a transformer substation power supply system, which comprises: the system comprises a first alternating current power supply, a second alternating current power supply, a first protection device, a second protection device and a dual-power switching system; when the first alternating current power supply supplies power and the alternating current load is grounded with high resistance, the first protection device is disconnected with the first alternating current power supply, and the first protection device controls the dual-power switching system not to switch to the second alternating current power supply for power supply; when the second alternating current power supply supplies power and the alternating current load is grounded with high resistance, the second protection device is disconnected with the second alternating current power supply, and the second protection device controls the dual-power switching system not to switch to the first alternating current power supply for power supply. The invention ensures that electrical equipment in the transformer substation is powered by normal alternating current or direct current, thereby ensuring the stable operation of the electrical equipment.

Description

Substation power supply system

Technical Field

The invention relates to the technical field of power engineering, in particular to a transformer substation power supply system.

Background

The alternating current load (such as a main transformer cooler power supply, a main transformer spraying fire-fighting power supply and the like) of the alternating current system of the transformer substation generally adopts a double-power switching function. As shown in fig. 1, when the ac load main power supply loses power, the ac load main power supply is automatically switched to the second ac power supply for power supply. The first alternating current power supply and the second alternating current power supply come from a first bus and a second bus of the transformer substation respectively so as to ensure the power supply reliability of alternating current load, but meanwhile, the automatic switching function of double power supplies also brings about certain potential safety hazards of power supply.

With continued reference to fig. 1, when the ac load is grounded with high resistance, the ac system flows through zero sequence current, and only the incoming line switch 11QF of the first bus and the incoming line switch 22QF of the second bus in the ac system have zero sequence protection function. Therefore, the incoming line switch 11QF of the first bus of the upper stage of the first alternating current power supply senses zero sequence current trip and locks 1ATS automatic switching function, the alternating current load double power supply switching function senses power failure of the first alternating current power supply, the power supply switching device does not have a locking function and can automatically switch to the second alternating current power supply to supply power, and meanwhile, faults are brought to the second bus, so that the incoming line switch 22QF of the second bus of the upper stage of the second alternating current power supply senses zero sequence current trip and locks 2ATS automatic switching function. The first bus and the second bus of the transformer substation lose voltage, alternating current power supply and direct current system power supply of electrical equipment in the transformer substation are affected, and safe and stable operation of the transformer substation equipment is seriously affected.

Disclosure of Invention

The invention provides a transformer substation power supply system which aims to solve the problem that the first bus and the second bus of a transformer substation lose voltage due to high-resistance ground faults of alternating current loads.

According to an aspect of the present invention, there is provided a substation power supply system, the system comprising: the system comprises a first alternating current power supply, a second alternating current power supply, a first protection device, a second protection device and a dual-power switching system;

The first alternating current power supply is connected to the first protection device, and the second alternating current power supply is connected to the second protection device; the first protection device and the second protection device are connected with the dual-power switching system; the dual power supply switching system is connected with an alternating current load;

When the first alternating current power supply supplies power and the alternating current load is grounded with high resistance, the first protection device is disconnected with the first alternating current power supply, and the first protection device controls the dual-power switching system not to switch to the second alternating current power supply for power supply; when the second alternating current power supply supplies power and the alternating current load is grounded with high resistance, the second protection device is disconnected with the second alternating current power supply, and the second protection device controls the dual-power switching system not to switch to the first alternating current power supply for power supply.

According to the technical scheme, the transformer substation power supply system is provided, the first protection device and the second protection device are arranged, so that when the first alternating current power supply supplies power and an alternating current load is grounded in a high resistance mode or when the second alternating current power supply supplies power and the alternating current load is grounded in a high resistance mode, the connection with the first alternating current power supply or the second alternating current power supply is automatically disconnected, and meanwhile, the double power supply switching system has a locking function, and the first protection device or the second protection device can control the double power supply switching system not to perform a power supply switching function. The problem that the first bus is out of voltage due to the fact that the incoming line switch (11 QF) of the first bus at the upper level of the first alternating current power supply senses zero-sequence current tripping and locks an automatic switching function is avoided, and the problem that the first bus and the second bus of a transformer substation are out of voltage simultaneously due to the fact that the incoming line switch (22 QF) of the second bus at the upper level of the second alternating current power supply senses zero-sequence current tripping and locks the automatic switching function after double power supplies are automatically switched is also avoided. The electric equipment in the transformer substation can normally supply alternating current or direct current, so that the stable operation of the electric equipment is ensured.

It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the invention or to delineate the scope of the invention. Other features of the present invention will become apparent from the description that follows.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a prior art substation power supply system;

Fig. 2 is a schematic structural diagram of a substation power supply system according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of another substation power supply system according to an embodiment of the present invention;

Fig. 4 is a schematic structural diagram of another substation power supply system according to an embodiment of the present invention.

Detailed Description

In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Fig. 2 is a schematic structural diagram of a substation power supply system according to an embodiment of the present invention. As shown in fig. 2, the system includes: a first alternating current power supply 1, a second alternating current power supply 2, a first protection device 3, a second protection device 4 and a dual power switching system 5.

The first alternating current power supply 1 is connected to the first protection device 3, and the second alternating current power supply 2 is connected to the second protection device 4; the first protection device 3 and the second protection device 4 are connected with a dual power supply switching system 5; the dual power switching system 5 is connected to an ac load 6.

When the first alternating current power supply 1 supplies power and the alternating current load 6 is grounded with high resistance, the first protection device 3 is disconnected from the first alternating current power supply 1, and the first protection device 3 controls the dual-power switching system 5 not to switch to the second alternating current power supply 2 for supplying power; when the second ac power source 2 supplies power and the ac load 6 is grounded with high resistance, the second protection device 4 disconnects the second ac power source 2, and the second protection device 4 controls the dual-power switching system 5 not to switch to the first ac power source 1 for supplying power.

In the embodiment of the invention, the ac load 6 is a load part having a certain energy-consuming power for the current and the voltage in the power system. By way of example, the ac load 6 may be a main transformer cooler power supply, a circuit breaker operation, an energy storage and heating power supply, or a main transformer spray fire power supply, etc.

Specifically, the first ac power source 1 and the second ac power source 2 are respectively from two sections of ac buses of the substation, and by way of example, the first ac power source 1 may be from a first bus, and the second ac power source 2 may be from a second bus. The first ac power source 1 may be a main power supply of the ac load 6, and the second ac power source 2 may be a main power supply of the ac load 6.

The first ac power source 1 is connected to the first protection device 3, and ac power is supplied to the first protection device 3. The second ac power source 2 is connected to the second protection device 4, and ac power is connected to the second protection device 4. The first protection device 3 and the second protection device 4 are connected with the dual power supply switching system 5, the dual power supply switching system 5 has a locking function, and the first protection device 3 and the second protection device 4 can control the power supply switching function of the dual power supply switching system 5. The dual power supply switching system 5 is connected with an ac load, the first ac power supply 1 can supply power to the ac load 6 through the first protection device 3 and the dual power supply switching system 5, and the second ac power supply 2 can also supply power to the ac load 6 through the second protection device 5 and the dual power supply switching system 5.

When the first ac power source 1 supplies power to the ac load 6 and the ac load 6 has a high-resistance ground fault, the first protection device 3 induces a zero-sequence current to automatically disconnect the connection with the first ac power source 1, and meanwhile, the first protection device 3 also controls the dual-power switching system 5 not to switch to the second ac power source 2 for supplying power. When the second ac power supply 2 supplies power to the ac load 6 and the ac load 6 has a high-resistance ground fault, the second protection device 4 induces a zero-sequence current to automatically disconnect the connection with the second ac power supply 2, and the second protection device 4 also controls the dual-power switching system 5 not to switch to the first ac power supply 1 for supplying power.

According to the technical scheme provided by the embodiment of the invention, the transformer substation power supply system is provided with the first protection device and the second protection device, so that when the first alternating current power supply supplies power and the alternating current load is grounded in a high resistance mode or when the second alternating current power supply supplies power and the alternating current load is grounded in a high resistance mode, the connection with the first alternating current power supply or the second alternating current power supply is automatically disconnected, and meanwhile, the dual power supply switching system has a locking function, so that the first protection device or the second protection device can control the dual power supply switching system not to perform a power supply switching function. The problem that the first bus is out of voltage due to the fact that the incoming line switch (11 QF) of the first bus at the upper level of the first alternating current power supply senses zero-sequence current tripping and locks an automatic switching function is avoided, and the problem that the first bus and the second bus of a transformer substation are out of voltage simultaneously due to the fact that the incoming line switch (22 QF) of the second bus at the upper level of the second alternating current power supply senses zero-sequence current tripping and locks the automatic switching function after double power supplies are automatically switched is also avoided. The electric equipment in the transformer substation can normally supply alternating current or direct current, so that the stable operation of the electric equipment is ensured.

With continued reference to fig. 2, when the first ac power source 1 supplies power normally and the ac load 6 operates normally, the first protection device 3 does not operate, the first ac power source 1 is connected to the ac load 6 through the first protection device 3 and the dual power switching system 5, and the first ac power source 1 supplies power 6 to the ac load.

When the first ac power supply 1 supplies power and a power failure occurs, the first protection device 3 does not operate, and the dual power switching system 5 automatically controls and switches to supply power to the second ac power supply 2.

Specifically, when the first ac power source 1 supplies power and the ac load 6 operates normally, that is, the first ac power source 1 and the ac load 6 do not have any fault, the first protection device 3 does not act at this time, that is, the first protection device 3 does not disconnect from the first ac power source 1, and the dual power switching system 5 is not controlled to switch power. The first alternating current power supply 1 is connected to an alternating current load 6 through a first protection device 3 and a dual power supply switching system 5, and the first alternating current power supply 1 supplies power to the alternating current load 6. At this time, the first ac power supply 1 has no failure, and the dual power switching system 5 does not perform the power switching function.

When the first ac power source 1 supplies power but a power failure occurs, the power failure may cause the first ac power source 1 to lose voltage. At this time, the first protection device 3 does not operate, that is, the first protection device 3 does not disconnect from the first ac power source 1, and the dual power switching system 5 is not controlled to perform power switching. Because the first ac power source 1 loses voltage, the dual power switching system 5 automatically controls and switches to the second ac power source 2 to supply power to the ac load 6.

With continued reference to fig. 2, when the second ac power source 2 supplies power normally and the ac load 6 operates normally, the second protection device 4 does not operate, the second ac power source 2 is connected to the ac load 6 through the second protection device 4 and the dual power switching system 5, and the second ac power source 2 supplies power to the ac load 6.

When the second ac power source 2 supplies power and a power failure occurs, the second protection device 4 does not operate, and the dual power switching system 5 automatically controls and switches to supply power to the first ac power source 1.

Specifically, when the second ac power source 2 supplies power and the ac load 6 operates normally, that is, no fault occurs in both the second ac power source 2 and the ac load 6, the second protection device 4 does not act, that is, the second protection device 4 does not disconnect from the second ac power source 2, and the dual power switching system 5 is not controlled to switch power. The second alternating current power supply 2 is connected to the alternating current load 6 through the second protection device 4 and the dual power supply switching system 5, and the second alternating current power supply 2 supplies power to the alternating current load 6. At this time, the second ac power supply 2 is free from a failure, and the dual power switching system 5 does not perform a power switching function.

When the second ac power source 2 supplies power but a power failure occurs, the power failure may cause the second ac power source 2 to lose voltage. At this time, the second protection device 4 does not operate, that is, the second protection device 4 does not disconnect from the second ac power supply 2, and the dual power switching system 5 is not controlled to perform power switching. Due to the voltage loss of the second ac power supply 2, the dual power switching system 5 automatically controls and switches to the first ac power supply 1 to supply power to the ac load 6.

Fig. 3 is a schematic structural diagram of another substation power supply system according to an embodiment of the present invention. As shown in fig. 3, the first protection device 3 includes: the first power supply incoming line is empty to open QF1, a first current transformer L1, a first shunt release M1 and a first electronic switch S1.

The first power supply inlet wire is connected with the first alternating current power supply 1 in a hollow-open mode QF1, the first alternating current power supply 1 is connected with the dual-power switching system 5 through the first power supply inlet wire is connected with the first current transformer L1 and the first shunt release M1 in a hollow-open mode QF1 and the first current transformer L1, and the first electronic switch S1 is also used for being connected with an external power supply 7.

When the first alternating current power supply 1 supplies power and the alternating current load 6 is grounded with high resistance, the first current transformer L1 outputs a first current to control the first electronic switch S1 to be closed, the external power supply 7 supplies power to the first shunt release M1 through the first electronic switch S1, the first shunt release M1 controls the first power inlet wire to be opened and the double-power switching system 5 is not switched to the second alternating current power supply 2 for supplying power.

In the embodiment of the present invention, the first power supply incoming line air-break QF1 is a switching device for controlling whether the first ac power supply 1 can be connected to the dual power supply switching system 5. The first current transformer L1 is a single-turn through zero-sequence current transformer and is a component for inducing zero-sequence current and converting the zero-sequence current into first current to be output. The first electronic switch S1 is a switching device for controlling whether the external power supply 7 supplies power to the first shunt release M1. The first shunt release M1 is a component for remotely operating the shunt release.

Specifically, the first ac power supply 1 includes an A1 phase line, a B1 phase line, a C1 phase line, and a first neutral line N1, where the A1 phase line, the B1 phase line, and the C1 phase line are connected to the first power supply incoming line open QF1 and connected to the dual power supply switching system 5 through the first current transformer L1 when the first power supply incoming line open QF1 is normally closed, and the first neutral line N1 directly passes through the first current transformer L1 and connected to the dual power supply switching system 5. The first current transformer L1 is connected to the first electronic switch S1, and the first electronic switch S1 is also connected to the first shunt release M1 and the external power supply 7.

When the first alternating current power supply 1 supplies power to the alternating current load 6 but the alternating current load 6 has a high-resistance grounding fault, the A1 phase line, the B1 phase line, the C1 phase line and the first zero line N1 pass through the first current transformer L1, the first current transformer L1 senses zero sequence current and converts the zero sequence current into first current to be output to the first electronic switch S1, the first electronic switch S1 is closed, the external power supply 7 supplies power to the first shunt release M1 through the first electronic switch S1, the first shunt release M1 remotely controls the first power inlet wire to be disconnected by the empty switch QF1, the first protection device 3 is disconnected with the first alternating current power supply 1, and meanwhile, the first shunt release M1 remotely controls the dual power switching system 5 not to be switched to the second alternating current power supply 2 for supplying power.

With continued reference to fig. 3, when the first ac power source 1 supplies power normally and the ac load 6 operates normally, the first electronic switch S1 is turned off, the first power supply incoming line air switch QF1 is closed normally, the first ac power source 1 is connected to the ac load 6, and the first ac power source 1 supplies power to the ac load 6.

When the first alternating current power supply 1 supplies power and a power failure occurs, the first electronic switch S1 is opened, the first power inlet wire air-break QF1 is normally closed, and the dual power supply switching system 5 automatically controls switching to the second alternating current power supply 2 for supplying power.

Specifically, when the first ac power source 1 supplies power and the ac load 6 operates normally, that is, the first ac power source 1 and the ac load 6 do not have any fault, the first current transformer L1 will not output the first current to the first electronic switch S1, the first electronic switch S1 is opened, the first shunt release M1 does not act, the first power inlet wire air-break QF1 is normally closed, and the first shunt release M1 will not control the dual power switching system 5 to not perform the power switching function. The first alternating current power supply 1 is connected to an alternating current load 6 through a first power supply incoming line air switch QF1, a first current transformer L1 and a dual power supply switching system 5, and the first alternating current power supply 1 supplies power to the alternating current load 6. At this time, the first ac power supply 1 has no failure, and the dual power switching system 5 does not perform the power switching function.

When the first ac power source 1 supplies power but a power failure occurs, the power failure may cause the first ac power source 1 to lose voltage. At this time, the first current transformer L1 will not output the first current to the first electronic switch S1, the first electronic switch S1 is opened, the first shunt release M1 does not act, the first power supply incoming line air-break QF1 is normally closed, and the first shunt release M1 will not control the dual power supply switching system 5 to not perform the power supply switching function. Because the first ac power source 1 loses voltage, the dual power switching system 5 automatically controls and switches to the second ac power source 2 to supply power to the ac load 6.

With continued reference to fig. 3, the second protection device 4 comprises: the second power supply inlet wire is empty to open QF2, second current transformer L2, second shunt release M2 and second electronic switch S2.

The second power supply inlet wire is empty to open QF2 and is connected with second alternating current power supply 2, and second alternating current power supply 2 is through empty QF2 of second power supply inlet wire and second current transformer L2 access dual power switching system 5, and second electronic switch S2 is connected with second current transformer L2 and second shunt release M2, still is used for accessing external power supply 7.

When the second ac power supply 2 supplies power and the ac load 6 is grounded with high resistance, the second current transformer L2 outputs a second current to control the second electronic switch S2 to be closed, the external power supply 7 supplies power to the second shunt release M2 through the second electronic switch S2, the second shunt release M2 controls the second power supply inlet wire to be opened and the dual power supply switching system 5 does not switch to the first ac power supply 1 to supply power.

In the embodiment of the present invention, the second power supply incoming line air-break QF2 is a switching device for controlling whether the second ac power supply 2 can be connected to the dual power supply switching system 5. The second current transformer L2 is a single-turn through zero-sequence current transformer and is a component for inducing zero-sequence current and converting the zero-sequence current into second current to be output. The second electronic switch S2 is a switching device for controlling whether the external power supply 7 supplies power to the second shunt release M2. The second shunt release M2 is a component for remotely operating the shunt release.

Specifically, the second ac power supply 2 includes an A2 phase line, a B2 phase line, a C2 phase line, and a second neutral line N2, where the A2 phase line, the B2 phase line, and the C2 phase line are connected to the second power supply incoming line open QF2 and connected to the dual power supply switching system 5 through the second current transformer L2 when the second power supply incoming line open QF2 is normally closed, and the second neutral line N2 directly passes through the second current transformer L2 and connected to the dual power supply switching system 5. The second current transformer L2 is connected to the second electronic switch S2, and the second electronic switch S2 is also connected to the second shunt release M2 and the external power supply 7.

When the second ac power supply 2 supplies power to the ac load 6 but the ac load 6 has a high-resistance ground fault, the A2 phase line, the B2 phase line, the C2 phase line and the second zero line N2 pass through the second current transformer L2, the second current transformer L2 senses zero sequence current and converts the zero sequence current into second current to be output to the second electronic switch S2, the second electronic switch S2 is closed, the external power supply 7 supplies power to the second shunt release M2 through the second electronic switch S2, the second shunt release M2 remotely controls the second power supply incoming line to be disconnected by the empty switch QF2, the second protection device 4 is disconnected with the second ac power supply 2, and meanwhile, the second shunt release M2 remotely controls the dual power supply switching system 5 not to be switched to supply power to the first ac power supply 1.

With continued reference to fig. 3, when the second ac power source 2 supplies power and the ac load 6 operates normally, the second electronic switch S2 is turned off, the second power supply incoming line air switch QF2 is normally closed, the second ac power source 2 is connected to the ac load 6, and the second ac power source 2 supplies power to the ac load 6.

When the second alternating current power supply 2 supplies power and has power failure, the second electronic switch S2 is opened, the second power inlet wire air switch QF2 is normally closed, and the dual power supply switching system 5 automatically controls switching to the first alternating current power supply 1 for supplying power.

Specifically, when the second ac power source 2 supplies power and the ac load 6 operates normally, that is, no fault occurs in both the second ac power source 2 and the ac load 6, the second current transformer L2 will not output the second current to the second electronic switch S2, the second electronic switch S2 is turned off, the second shunt release M2 does not act, the second power inlet wire air switch QF2 is normally closed, and the second shunt release M2 will not control the dual power switching system 5 to not perform the power switching function. The second alternating current power supply 2 is connected to the alternating current load 6 through a second power supply incoming line air switch QF2, a second current transformer L2 and a dual power supply switching system 5, and the second alternating current power supply 2 supplies power to the alternating current load 6. At this time, the second ac power supply 2 is free from a failure, and the dual power switching system 5 does not perform a power switching function.

When the second ac power source 2 supplies power but a power failure occurs, the power failure may cause the second ac power source 2 to lose voltage. At this time, the second current transformer L2 will not output the second current to the second electronic switch S2, the second electronic switch S2 is turned off, the second shunt release M2 does not act, the second power supply incoming line air-break QF2 is normally closed, and the second shunt release M2 will not control the dual power supply switching system 5 to not perform the power supply switching function. Due to the voltage loss of the second ac power supply 2, the dual power switching system 5 automatically controls and switches to the first ac power supply 1 to supply power to the ac load 6.

Fig. 4 is a schematic structural diagram of another substation power supply system according to an embodiment of the present invention. As shown in fig. 4, the dual power switching system 5 includes: a first ac contactor KM1, a second ac contactor KM2, a first switch K1, a second switch H1, a third switch K2, and a fourth switch H2.

The first alternating current contactor KM1 comprises a first power end A1, a second power end A2, first normally-open contacts L1-T1, second normally-open contacts L2-T2, third normally-open contacts L3-T3, fourth normally-open contacts N0-N1 and first normally-closed contacts NC1-NC2; the second alternating current contactor KM2 comprises a third power end A3, a fourth power end A4, fifth normally-open contacts L4-T4, sixth normally-open contacts L5-T5, seventh normally-open contacts L6-T6, eighth normally-open contacts N2-N3 and second normally-closed contacts NC3-NC4; the first end L1 of the first normally open contact L1-T1, the first end L2 of the second normally open contact L2-T2, the first end L3 of the third normally open contact L3-T3 and the first end N0 of the fourth normally open contact N0-N1 are all connected with the first protection device 3, and the first power end A1 is connected with the first end L2 of the second normally open contact L2-T2.

The first end L4 of the fifth normally open contact L4-T4, the first end L5 of the sixth normally open contact L5-T5, the first end L6 of the seventh normally open contact L6-T6, and the first end N2 of the eighth normally open contact N2-N3 are all connected to the second protection device 4, and the third power supply end A3 is connected to the first end L5 of the sixth normally open contact L5-T5.

The second end T1 of the first normally open contact L1-T1, the second end T2 of the second normally open contact L2-T2, the second end T3 of the third normally open contact L3-T3 and the second end N1 of the fourth normally open contact N0-N1 are respectively connected with the second end T4 of the fifth normally open contact L4-T4, the second end T5 of the sixth normally open contact L5-T5, the second end T6 of the seventh normally open contact L6-T6 and the second end N3 of the eighth normally open contact N2-N3; the first end NC1 of the first normally-closed contact NC1-NC2 is connected with the first end L6 of the seventh normally-open contact L6-T6, and the first end NC3 of the second normally-closed contact NC3-NC4 is connected with the first end L3 of the third normally-open contact L3-T3.

The first switch K1 and the second switch H1 are connected in series between the second end NC2 and the fourth power end A4 of the first normally-closed contacts NC1-NC2, and the third switch K2 and the fourth switch H2 are connected in series between the second power end A2 and the second end NC4 of the second normally-closed contacts NC3-NC 4.

When the first alternating current power supply 1 supplies power and the alternating current load 6 is grounded with high resistance, the first protection device 3 is disconnected with the first alternating current power supply 1, the first protection device 3 controls the first switch K1 and the third switch K2 to be disconnected, and the dual power supply switching system 5 is not switched to the second alternating current power supply 2 for supplying power; when the second ac power source 2 supplies power and the ac load 6 is grounded with high resistance, the second protection device 4 is disconnected from the second ac power source 2, and the second protection device 4 controls the second switch H1 and the fourth switch H2 to be disconnected, so that the dual-power switching system 5 does not switch to the first ac power source 1 to supply power.

In the embodiment of the invention, the first ac contactor KM1 and the second ac contactor KM2 are an electrical switching apparatus, and are mainly used for a switching circuit, a control circuit for controlling operation and protection of electrical equipment, and equipment.

Specifically, an A1 phase line, a B1 phase line and a C1 phase line of the first alternating current power supply 1 are respectively connected with a first end L1 of a first normally-open contact L1-T1, a first end L2 of a second normally-open contact L2-T2 and a first end L3 of a third normally-open contact L3-T3 through a first power supply incoming line blank QF1 and a first current transformer L1, and a first zero line N1 is connected with a first end N0 of a fourth normally-open contact N0-N1 through the first current transformer L1. The A2 phase line, the B2 phase line and the C2 phase line of the second alternating current power supply 2 are respectively connected with the first end L4 of the fifth normally-open contact L4-T4, the first end L5 of the sixth normally-open contact L5-T5 and the first end L6 of the seventh normally-open contact L6-T6 through the second power supply incoming line free-open QF2 and the second current transformer L2, and the second zero line N2 is connected with the first end N2 of the eighth normally-open contact N2-N3 through the second current transformer L2.

When the first alternating current power supply 1 supplies power and the alternating current load 6 has high-resistance ground fault, the first shunt release M1 controls the first power supply incoming line to be opened by the empty switch QF1, and also controls the first switch K1 and the third switch K2 to be opened, the first power supply end A1 is connected with the first end L2 of the second normally open contact L2-T2, the second power supply end A2 is connected with the first end L3 of the third normally open contact L3-T3 through the third switch K2, the fourth switch H2 and the second normally closed contact NC3-NC4, and the voltages of the B1 phase line and the C1 phase line cannot be connected with the first end L2 of the second normally open contact L2-T2 and the first end L3 of the third normally open contact L3-T3 due to the fact that the first power supply incoming line is opened by the empty switch QF1, the first power supply end A1 and the second power supply end A2 are in power failure, the first alternating current contactor KM1 is in magnetism failure, the first normally open contact L1-T1, the second normally open contact L2-T2, the third normally open contact L3-NC 2 and the normally closed contact NC 1-N2 are opened. At this time, the second power inlet wire air-break QF2 is normally closed, the third power end A3 is normally powered on through the first end L5 of the sixth normally open contact L5-T5, but the fourth power end A4 is connected with the first end L6 of the seventh normally open contact L6-T6 through the second switch H1, the first switch K1 and the first normally closed contact NC1-NC2, and since the first switch K1 is opened, the fourth power end A4 is not powered on, the second ac contactor KM2 is not excited, the fifth normally open contact L4-T4, the sixth normally open contact L5-T5, the seventh normally open contact L6-T6, and the eighth normally open contact N2-N3 are opened, and the dual power switching system 5 cannot be switched to the second ac power source 2 for power supply.

When the second alternating current power supply 2 supplies power and the alternating current load 6 has high-resistance ground fault, the second shunt release M2 controls the second power supply incoming line to be opened by the empty switch QF2, and also controls the second switch H1 and the fourth switch H2 to be opened, the third power supply end A3 is connected with the first end L5 of the sixth normally open contact L5-T5, the fourth power supply end A4 is connected with the first end L6 of the seventh normally open contact L6-T6 through the first switch K1, the second switch H1 and the first normally closed contact NC1-NC2, and the second power supply incoming line is opened by the empty switch QF2, so that the voltages of the B2 phase line and the C2 phase line cannot be connected to the first end L5 of the sixth normally open contact L5-T5 and the first end L6 of the seventh normally open contact L6-T6, the third power supply end A3 and the fourth power supply end A4 are in power loss, the second alternating current contactor KM2 is in magnetism loss, the fifth normally open contact L4-T4, the sixth normally open contact L5-T5, the seventh normally open contact L6-NC 2 and the eighth normally closed contact NC 2-N3-N4 are opened. At this time, the first power inlet wire air switch QF1 is normally closed, the first power end A1 is normally powered on through the first end L2 of the second normally open contact L2-T2, but the second power end A2 is connected with the first end L3 of the third normally open contact L3-T3 through the third switch K2, the fourth switch H2 and the second normally closed contact NC3-NC4, and since the fourth switch H2 is opened, the second power end A2 is not powered on, the first ac contactor KM1 is not excited, the first normally open contact L1-T1, the second normally open contact L2-T2, the third normally open contact L3-T3 and the fourth normally open contact N0-N1 are opened, and the dual power switching system 5 cannot be switched to the first ac power supply 1 for power supply.

With continued reference to fig. 4, when the first ac power source 1 supplies power normally and the ac load 6 operates normally, the first protection device 3 does not operate, the first power source terminal A1 and the second power source terminal A2 are energized, the first ac contactor KM1 is energized, the first normally open contact L1-T1, the second normally open contact L2-T2, the third normally open contact L3-T3, and the fourth normally open contact N0-N1 are closed, and the first normally closed contact NC1-NC2 is opened; the fourth power end A4 is unpowered, the second alternating current contactor KM2 is not excited, the first alternating current power supply 1 is connected to the alternating current load 6, and the first alternating current power supply 1 supplies power to the alternating current load 6.

When the first alternating current power supply 1 supplies power and has a power failure, the first protection device 3 does not act, the first power supply end A1 and the second power supply end A2 lose power, the first alternating current contactor KM1 loses magnetism, the first normally open contact L1-T1, the second normally open contact L2-T2, the third normally open contact L3-T3 and the fourth normally open contact N0-N1 are opened, and the first normally closed contact NC1-NC2 is closed; the third power supply end A3 and the fourth power supply end A4 are powered on, the second alternating current contactor KM2 is excited, the fifth normally-open contact L4-T4, the sixth normally-open contact L5-T5, the seventh normally-open contact L6-T6 and the eighth normally-open contact N2-N3 are closed, and the second normally-closed contact NC3-NC4 is opened; the second alternating current power supply 2 is connected to the alternating current load 6, and the second alternating current power supply 2 supplies power to the alternating current load 6.

Specifically, when the first ac power source 1 supplies power and the ac load 6 operates normally, that is, the first ac power source 1 and the ac load 6 have no fault, at this time, the first power supply incoming line empty switch QF1 is normally closed, the first switch K1, the second switch H1, the third switch K2 and the fourth switch H2 are normally closed, the first power supply end A1 is normally powered through the first end L2 of the second normally open contact L2-T2, and the second power supply end A2 is connected with the first end L3 of the third normally open contact L3-T3 through the third switch K2, the fourth switch H2 and the second normally closed contact NC3-NC4, and the second power supply end A2 is normally powered. The first alternating current contactor KM1 is excited, the first normally open contact L1-T1, the second normally open contact L2-T2, the third normally open contact L3-T3 and the fourth normally open contact N0-N1 are closed, the first normally closed contact NC1-NC2 is opened, the first alternating current power supply 1 is connected to an alternating current load 6, and the first alternating current power supply 1 supplies power to the alternating current load 6. Since the first normally-closed contacts NC1 to NC2 are opened, the fourth power supply terminal A4 is deenergized, and the second ac contactor KM2 is deenergized.

When the first alternating current power supply 1 supplies power and has a power failure, the B1 phase line and the C1 phase line lose power due to the power failure, so that the first power end A1 and the second power end A2 lose power, the first alternating current contactor KM1 loses magnetism, the first normally-open contact L1-T1, the second normally-open contact L2-T2, the third normally-open contact L3-T3 and the fourth normally-open contact N0-N1 are disconnected, and the first normally-closed contact NC1-NC2 is closed. The third power supply end A3 and the fourth power supply end A4 are normally powered on, the second alternating current contactor KM2 is excited, the fifth normally-open contact L4-T4, the sixth normally-open contact L5-T5, the seventh normally-open contact L6-T6 and the eighth normally-open contact N2-N3 are closed, and the second normally-closed contact NC3-NC4 is opened; the second alternating current power supply 2 is connected to the alternating current load 6, and the second alternating current power supply 2 supplies power to the alternating current load 6.

With continued reference to fig. 4, when the second ac power source 2 supplies power and the ac load 6 operates normally, the second protection device 4 does not operate, the third power source terminal A3 and the fourth power source terminal A4 get power, the second ac contactor KM2 is excited, the fifth normally open contact L4-T4, the sixth normally open contact L5-T5, the seventh normally open contact L6-T6, the eighth normally open contact N2-N3 are closed, and the second normally closed contact NC3-NC4 is opened; the second power supply end A2 is unpowered, the first alternating current contactor KM1 is not excited, the second alternating current power supply 2 is connected to an alternating current load 6, and the second alternating current power supply 2 supplies power to the alternating current load 6.

When the second alternating current power supply 2 supplies power and has a power failure, the second protection device 4 does not act, the third power supply end A3 and the fourth power supply end A4 lose power, the second alternating current contactor KM2 loses magnetism, the fifth normally-open contact L4-T4, the sixth normally-open contact L5-T5, the seventh normally-open contact L6-T6 and the eighth normally-open contact N2-N3 are opened, and the second normally-closed contact NC3-NC4 is closed; the first power supply end A1 and the second power supply end A2 are powered on, the first alternating current contactor KM1 is excited, the first normally-open contact L1-T1, the second normally-open contact L2-T2, the third normally-open contact L3-T3 and the fourth normally-open contact N0-N1 are closed, and the first normally-closed contact NC1-NC2 is opened; the first alternating current power supply 1 is connected to the alternating current load 6, and the first alternating current power supply 1 supplies power to the alternating current load 6.

Specifically, when the second ac power supply 2 supplies power and the ac load 6 operates normally, that is, the second ac power supply 2 and the ac load 6 have no fault, at this time, the second power supply incoming line empty switch QF2 is normally closed, the first switch K1, the second switch H1, the third switch K2 and the fourth switch H2 are normally closed, the third power supply terminal A3 is normally powered through the first terminal L5 of the sixth normally open contact L5-T5, and the fourth power supply terminal A4 is connected with the first terminal L6 of the seventh normally open contact L6-T6 through the second switch H1, the first switch K1 and the first normally closed contact NC1-NC 2. The second alternating current contactor KM2 is excited, the fifth normally-open contact L4-T4, the sixth normally-open contact L5-T5, the seventh normally-open contact L6-T6 and the eighth normally-open contact N2-N3 are closed, the second normally-closed contact NC3-NC4 is opened, the second alternating current power supply 2 is connected to the alternating current load 6, and the second alternating current power supply 2 supplies power to the alternating current load 6. Since the second normally-closed contacts NC3 to NC4 are opened, the second power supply terminal A2 is deenergized, and the first ac contactor KM1 is deenergized.

When the second ac power supply 2 supplies power and a power failure occurs, the B2 phase line and the C2 phase line lose power due to the power failure, so that the third power supply end A3 and the fourth power supply end A4 lose power, the second ac contactor KM2 loses magnetism, the fifth normally open contact L4-T4, the sixth normally open contact L5-T5, the seventh normally open contact L6-T6, and the eighth normally open contact N2-N3 are opened, and the second normally closed contact NC3-NC4 is closed. The first power supply end A1 and the second power supply end A2 are normally powered, the first alternating current contactor KM1 is excited, the first normally-open contact L1-T1, the second normally-open contact L2-T2, the third normally-open contact L3-T3 and the fourth normally-open contact N0-N1 are closed, and the first normally-closed contact NC1-NC2 is opened; the first alternating current power supply 1 is connected to the alternating current load 6, and the first alternating current power supply 1 supplies power to the alternating current load 6.

It should be appreciated that various forms of the flows shown above may be used to reorder, add, or delete steps. For example, the steps described in the present invention may be performed in parallel, sequentially, or in a different order, so long as the desired results of the technical solution of the present invention are achieved, and the present invention is not limited herein.

The above embodiments do not limit the scope of the present invention. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.

Claims (10)

1. A substation power supply system, comprising: the system comprises a first alternating current power supply, a second alternating current power supply, a first protection device, a second protection device and a dual-power switching system;

The first alternating current power supply is connected to the first protection device, and the second alternating current power supply is connected to the second protection device; the first protection device and the second protection device are connected with the dual-power switching system; the dual power supply switching system is connected with an alternating current load;

When the first alternating current power supply supplies power and the alternating current load is grounded with high resistance, the first protection device is disconnected with the first alternating current power supply, and the first protection device controls the dual power supply switching system not to switch to the second alternating current power supply for power supply; when the second alternating current power supply supplies power and the alternating current load is grounded with high resistance, the second protection device is disconnected from the second alternating current power supply, and the second protection device controls the dual power supply switching system not to switch to the first alternating current power supply for power supply.

2. The substation power supply system according to claim 1, wherein said first protection device is inactive when said first ac power source is supplying power normally and said ac load is operating normally, said first ac power source accessing said ac load through said first protection device and said dual power switching system, said first ac power source supplying power to said ac load;

when the first alternating current power supply supplies power and a power failure occurs, the first protection device does not act, and the dual power supply switching system automatically controls and switches to the second alternating current power supply to supply power.

3. The substation power supply system according to claim 1, wherein said second protection device is inactive when said second ac power source is supplying power normally and said ac load is operating normally, said second ac power source is accessing said ac load through said second protection device and said dual power switching system, said second ac power source supplying power to said ac load;

And when the second alternating current power supply supplies power and has power failure, the second protection device does not act, and the dual power supply switching system automatically controls and switches to the first alternating current power supply for supplying power.

4. The substation power supply system according to claim 1, wherein said first protection means comprises: the first power supply inlet wire is opened, the first current transformer, the first shunt release and the first electronic switch are arranged in the first shunt release;

The first power supply incoming line is connected with the first alternating current power supply, the first alternating current power supply is connected with the dual power supply switching system through the first power supply incoming line and the first current transformer, and the first electronic switch is connected with the first current transformer and the first shunt release and is also used for being connected with an external power supply;

When the first alternating current power supply supplies power and the alternating current load is grounded in a high resistance mode, the first current transformer outputs a first current to control the first electronic switch to be closed, the external power supply supplies power for the first shunt release through the first electronic switch, the first shunt release controls the first power supply incoming line to be opened and disconnected in a null mode, and the dual power supply switching system is not switched to supply power for the second alternating current power supply.

5. The substation power supply system according to claim 4, wherein when said first ac power source is supplying power normally and said ac load is operating normally, said first electronic switch is opened, said first power supply inlet is open and closed normally, said first ac power source is connected to said ac load, and said first ac power source supplies power to said ac load;

When the first alternating current power supply supplies power and has power failure, the first electronic switch is opened, the first power inlet wire is opened and normally closed, and the dual power supply switching system automatically controls switching to supply power to the second alternating current power supply.

6. The substation power supply system according to claim 1, wherein said second protection device comprises: the second power supply inlet wire is opened, the second current transformer, the second shunt release and the second electronic switch are arranged in the first shunt release;

The second power supply incoming line is connected with the second alternating current power supply, the second alternating current power supply is connected with the dual power supply switching system through the second power supply incoming line and the second current transformer, and the second electronic switch is connected with the second current transformer and the second shunt release and is also used for being connected with an external power supply;

when the second alternating current power supply supplies power and the alternating current load is grounded with high resistance, the second current transformer outputs a second current to control the second electronic switch to be closed, the external power supply supplies power for the second shunt release through the second electronic switch, the second shunt release controls the second power supply incoming line to be opened and disconnected, and the dual power supply switching system is not switched to the first alternating current power supply to supply power.

7. The substation power supply system according to claim 6, wherein when said second ac power source is supplying power normally and said ac load is operating normally, said second electronic switch is opened, said second power supply inlet is open and closed normally, said second ac power source is connected to said ac load, and said second ac power source supplies power to said ac load;

when the second alternating current power supply supplies power and has power failure, the second electronic switch is opened, the second power inlet wire is opened and normally closed, and the dual power supply switching system automatically controls switching to supply power to the first alternating current power supply.

8. The substation power supply system according to claim 1, wherein said dual power switching system comprises: a first ac contactor, a second ac contactor, a first switch, a second switch, a third switch, and a fourth switch;

the first alternating current contactor comprises a first power end, a second power end, a first normally-open contact, a second normally-open contact, a third normally-open contact, a fourth normally-open contact and a first normally-closed contact; the second alternating current contactor comprises a third power end, a fourth power end, a fifth normally-open contact, a sixth normally-open contact, a seventh normally-open contact, an eighth normally-open contact and a second normally-closed contact; the first end of the first normally-open contact, the first end of the second normally-open contact, the first end of the third normally-open contact and the first end of the fourth normally-open contact are all connected with the first protection device, and the first power supply end is connected with the first end of the second normally-open contact;

The first end of the fifth normally open contact, the first end of the sixth normally open contact, the first end of the seventh normally open contact and the first end of the eighth normally open contact are all connected with the second protection device, and the third power supply end is connected with the first end of the sixth normally open contact;

The second end of the first normally open contact, the second end of the second normally open contact, the second end of the third normally open contact and the second end of the fourth normally open contact are respectively connected with the second end of the fifth normally open contact, the second end of the sixth normally open contact, the second end of the seventh normally open contact and the second end of the eighth normally open contact; the first end of the first normally-closed contact is connected with the first end of the seventh normally-open contact, and the first end of the second normally-closed contact is connected with the first end of the third normally-open contact;

The first switch and the second switch are connected in series between the second end of the first normally-closed contact and the fourth power supply end, and the third switch and the fourth switch are connected in series between the second power supply end and the second end of the second normally-closed contact;

When the first alternating current power supply supplies power and the alternating current load is grounded with high resistance, the first protection device is disconnected with the first alternating current power supply, the first protection device controls the first switch and the third switch to be disconnected, and the dual-power switching system is not switched to the second alternating current power supply for power supply; when the second alternating current power supply supplies power and the alternating current load is grounded with high resistance, the second protection device is disconnected with the second alternating current power supply, the second protection device controls the second switch and the fourth switch to be disconnected, and the dual-power switching system is not switched to the first alternating current power supply for power supply.

9. The substation power supply system according to claim 8, wherein said first protection device is deactivated, said first power supply terminal and said second power supply terminal are energized, said first ac contactor is energized, said first normally open contact, said second normally open contact, said third normally open contact, and said fourth normally open contact are closed, and said first normally closed contact is open; the fourth power end is unpowered, the second alternating current contactor is not excited, the first alternating current power supply is connected to the alternating current load, and the first alternating current power supply supplies power to the alternating current load;

When the first alternating current power supply supplies power and has a power failure, the first protection device does not act, the first power end and the second power end lose power, the first alternating current contactor loses magnetism, the first normally-open contact, the second normally-open contact, the third normally-open contact and the fourth normally-open contact are opened, and the first normally-closed contact is closed; the third power end and the fourth power end are powered, the second alternating current contactor is excited, the fifth normally-open contact, the sixth normally-open contact, the seventh normally-open contact and the eighth normally-open contact are closed, and the second normally-closed contact is opened; the second alternating current power supply is connected to the alternating current load, and the second alternating current power supply supplies power to the alternating current load.

10. The substation power supply system according to claim 8, wherein when the second ac power source is supplying power normally and the ac load is operating normally, the second protection device is not operated, the third power source terminal and the fourth power source terminal are energized, the second ac contactor is excited, the fifth normally open contact, the sixth normally open contact, the seventh normally open contact, and the eighth normally open contact are closed, and the second normally closed contact is opened; the second power supply end is unpowered, the first alternating current contactor is not excited, the second alternating current power supply is connected to the alternating current load, and the second alternating current power supply supplies power to the alternating current load;

When the second alternating current power supply supplies power and has a power failure, the second protection device does not act, the third power end and the fourth power end lose power, the second alternating current contactor loses magnetism, the fifth normally-open contact, the sixth normally-open contact, the seventh normally-open contact and the eighth normally-open contact are opened, and the second normally-closed contact is closed; the first power end and the second power end are electrified, the first alternating current contactor is excited, the first normally-open contact, the second normally-open contact, the third normally-open contact and the fourth normally-open contact are closed, and the first normally-closed contact is opened; the first alternating current power supply is connected to the alternating current load, and the first alternating current power supply supplies power to the alternating current load.