KR20190091859A - Protection relay installation compliance inspection method and inspection apparatus - Google Patents

Abstract

According to one embodiment of the present invention, provided are a method for inspecting protection relay installation suitability and an inspection apparatus thereof. The method for inspecting protection relay installation suitability comprises: a current information generation step measuring a secondary current generated by a current transformer installed in each phase of a three-phase AC power line connected to a monitoring target, and generating information of the secondary current; a reconstruction step reconstructing a test current flowing in each phase of the three-phase AC power line based on the information of the secondary current; and a test result display step visually representing the reconstructed test current in a vector diagram manner. The three-phase current power line is open on one side and the other side is shorted based on the monitoring target, and the method for inspecting protection relay installation suitability is performed in an environment where a single-phase AC test current is applied between two phases of the three-phase AC power line of the opened one end.

Description

Protection relay installation compliance inspection method and inspection apparatus

The present invention relates to a protective relay installation suitability inspection method and inspection apparatus.

Power system consists of power generation, substation, transmission and distribution lines and loads organically and closely related to the generation and consumption of power. The power system is composed of a generator, a transformer, a bus, a transmission and distribution line, a load, and the like, and further includes various control devices, measuring devices, and protection devices for safe operation of the power system. These safeguards monitor each component of the power system for abnormalities and immediately isolate faults from the power system to minimize damage to the system as soon as an abnormality is detected.

The protective relay is a system failure based on the secondary current generated by the current flowing in each phase by a current transformer installed in the power line to measure the three-phase current flowing to the monitored object (transformer and / or generator). To judge. The protective relay operates normally when the current transformer is installed in the correct direction. If the current transformer is not installed correctly, the protection relay may malfunction, and the malfunction of the protection relay may damage the entire system. Therefore, a test operation determines whether the current transformer is installed correctly. This test run requires a lot of time and effort from the experts for the test run and the physical elements such as test power, transformer and measuring equipment. Therefore, there is a need for a method that can easily solve the test operation.

KR 10-1993-0024243 A

An object according to an embodiment of the present invention is a test that flows through a three-phase power line based on a secondary current generated by a current transformer installed in the three-phase power line to check the installation suitability of the protective relay installed in the transformer and / or the generator. It is to provide a protective relay installation suitability inspection method and inspection apparatus that can determine whether the current transformer is incorrectly connected by reconfiguring and visually displaying the current.

The protective relay installation compliance test apparatus according to an embodiment of the present invention, the measurement unit for measuring the secondary current generated by the current transformer installed in each phase of the three-phase AC power line connected to the monitoring target to generate the information of the secondary current A control unit for reconfiguring a test current flowing in each phase of the three-phase AC power line based on the information of the secondary current, and controlling a display unit to display the reconstructed test current in a vector diagram, and the reconstructed test current. The display unit visually represented in a vector diagram method, wherein the three-phase AC power line is open on one side and the other is shorted based on the monitoring target, single-phase AC test between two phases of the open one-phase three-phase AC power line Current can be applied.

The apparatus may further include an input unit configured to receive installation information of the monitoring target and the current transformer, and the controller may estimate a test current flowing in each phase of the three-phase AC power line in a state in which the current transformer is normally installed, based on the installation information. The display unit may further control the display unit to display the expected test current in a vector diagram, and the display unit may further visually display the expected test current in a vector diagram manner.

The apparatus may further include a test power supply connected between two phases of the three-phase AC power line to supply a single-phase AC test current.

In accordance with an embodiment of the present invention, a protective relay installation suitability test method may include: measuring current of a secondary current generated by a current transformer installed on each phase of a three-phase AC power line connected to a monitoring target to generate information of the secondary current; A generation step, a reconstruction step of reconstructing a test current flowing in each phase of the three-phase AC power line based on the information of the secondary current, and a test result display step of visually representing the reconstructed test current in a vector diagram manner. The three-phase AC power line may have one side open and the other side shorted based on the monitoring target, and a single-phase AC test current may be applied between two phases among the open one-phase three phase AC power lines.

Also, based on the installation information, an expected step of predicting a test current flowing in each phase of the three-phase AC power line in a state in which the current transformer is normally installed, and an expected result of visually representing the expected test current in a vector diagram manner. The display step may further include.

In addition, the current information generation step, reconstruction step, and test result display step is to apply the single-phase AC test current between the remaining one phase of the three-phase AC power line and one of the selected two phases, and at least once more Can be.

In addition, the current information generation step, reconstruction step, and test result display step may be performed in a digital protection relay having a vector diagram display function.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to this, the terms or words used in this specification and claims are not to be interpreted in a conventional and dictionary sense, and the inventors may appropriately define the concept of terms in order to best explain their invention in the best way possible. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

According to one embodiment of the present invention, in order to check the installation suitability of the protective relay installed in the transformer and / or generator, reconstruct the current flowing in the three-phase AC power line from the secondary current generated by the current transformer installed in the three-phase AC power line By predicting the test current with the current transformer installed correctly and visually displaying it using a vector diagram, the user can quickly and accurately confirm the installation suitability of the protective relay.

In addition, according to an embodiment of the present invention, a portable single-phase current source can be used as a test power supply, and a vector diagram of the test current based on the measured value of the actual current transformer and a vector diagram of the test current when the correct connection is made during the test operation is performed. Visual comparison makes it possible to simplify the equipment required for the installation suitability check of the protective relay and to reduce inspection time and costs.

1 is a circuit diagram configured to perform the protective relay installation compliance test method according to an embodiment of the present invention.
Figure 2 is a block diagram showing the configuration of a protective relay installation suitability inspection apparatus according to an embodiment of the present invention.
3 is a flowchart illustrating a process of performing a protective relay installation suitability test method according to an embodiment of the present invention.
Figure 4 is a detailed circuit diagram for performing the protective relay installation suitability test method according to an embodiment of the present invention.
FIG. 5 is a circuit diagram illustrating a current flow when a test current is applied to R phase and S phase according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating a vector diagram displayed on a display of a display unit of the inspection apparatus in the case of FIG. 5.
7 is a circuit diagram illustrating a current flow when a test current is applied to an S phase and a T phase according to an embodiment of the present invention.
FIG. 8 is a diagram illustrating a vector diagram displayed on the display of the display unit of the inspection apparatus in the case of FIG. 7.
9 is a circuit diagram illustrating a current flow when a test current is applied to the S phase and the T phase according to an embodiment of the present invention, and the current transformer is in a miswiring state.
FIG. 10 is a diagram illustrating a vector diagram displayed on the display of the display unit of the inspection apparatus in FIG. 9.

The objects, specific advantages and novel features of one embodiment of the present invention will become more apparent from the following detailed description and the preferred embodiments associated with the accompanying drawings. In the present specification, in adding reference numerals to the components of each drawing, it should be noted that the same components as possible, even if displayed on different drawings have the same number as possible. In addition, terms such as “one side”, “other side”, “first”, “second”, etc. are used to distinguish one component from another component, and a component is limited by the terms. no. Hereinafter, in describing one embodiment of the present invention, detailed descriptions of related well-known techniques that may unnecessarily obscure the subject matter of one embodiment of the present invention will be omitted.

Hereinafter, with reference to the accompanying drawings, an embodiment of the present invention will be described in detail.

1 is a circuit diagram configured to perform a protective relay installation compliance test method according to an embodiment of the present invention, Figure 2 is a block showing the configuration of the protective relay installation compliance test apparatus 100 according to an embodiment of the present invention It is a block diagram.

As shown in FIG. 1, the three-phase AC power lines r, s, and t connected to the monitoring target 40 are connected to the power system 50 through the breaker 30. The three-phase AC power line of one side P1 may be represented by R, S, and T, and the three-phase AC power line of the other side P2 may be represented by r, s, and t based on the monitoring target 40. The monitoring target 40 may include a generator 42 and a power transformer 41 when producing power, may include only the power transformer 41, and may include other power devices.

The protection relay 10 refers to a differential ratio protection relay and the like. When a failure occurs in the monitoring target 40, the failure is separated from the power system 50 and the monitoring target 40. 50) to prevent the spread.

Current transformers (CTs) are installed on each of the three-phase AC power lines on one side P1 and the other side P2 of the monitoring target 40. The current transformer 20 has a correct direction to be installed in the three-phase AC power line, one for each phase. In FIG. 1, when the current flowing in the three-phase AC power line connected to the monitoring target 40 in the steady state is equal to A1, the current transformer 20 installed in the three-phase AC power line is a secondary current generated by the current transformer 20. It is correct that the polarizer is installed so as to flow as shown.

If the phase in which the current transformer 20 is installed is changed or if the polarity direction in which the current transformer 20 is installed is incorrectly wired, the secondary current generated by the current transformer 20 is received and whether the monitoring target 40 is abnormal. The protection relay 10 for determining the operation cannot be performed normally.

As shown in Figure 1, in order to check the installation suitability of the protective relay 10 according to an embodiment of the present invention, the inspection device to measure the current generated by the current transformer 20 connected to the three-phase AC power line Install 100.

The protective relay installation compliance test apparatus 100 according to an embodiment of the present invention measures the secondary current generated by the current transformer 20 installed on each phase of the three-phase AC power line connected to the monitoring target 40. The measurement unit 120 generating information of the difference current, and reconstructs the test current It flowing in each phase of the three-phase AC power line based on the information of the secondary current, and reconstructs the reconstructed test current It. The controller 130 may control the display unit 140 to display the vector diagram, and the display unit 140 may visually display the reconstructed test current It in a vector diagram manner.

In addition, the protective relay installation suitability inspection apparatus 100 according to an embodiment of the present invention, the input unit 110, the communication unit 150 that can receive the installation information of the monitoring target 40 and / or the current transformer 20. The test power supply 160 may further include.

The measurement unit 120 directly receives or indirectly measures the secondary current generated by the current transformer 20 and collects information of the secondary current including the magnitude, phase, direction, and the like of the secondary current. The measurement unit 120 may optionally include components necessary for digitizing an analog current value to generate secondary current information, for example, an A / D converter, a filter, an AMP, a MUX, a DSP, and the like. The measuring unit 120 measures the secondary currents generated by the six current transformers 20 connected to the respective phases R, S, T, r, s, and t of the three-phase AC power line, respectively, and measures six secondary currents in real time. Information of the current may be provided to the controller 130.

The input unit 110 receives the installation information such as the monitoring target 40, the current transformer 20, the test power supply 160, the circuit structure of the three-phase AC power line, and provides it to the controller 130. The installation information is, for example, the angular displacement DYn11 of the power transformer 41, the rated voltages of the primary and secondary sides, the transformer ratio, the current ratio of the current transformer 20, the polarity direction, the installed phase information, the test power supply 160 ) May include information on two phases (for example, R and S) connected to each other, the magnitude of the test current (It), and the frequency. The input unit 110 may include a touch screen, a tablet panel, or another input device such as a keyboard.

The controller 130 receives the information of the secondary current generated by the measurement unit 120 and the installation information of the monitoring target 40, the current transformer 20, and the test power supply 160 provided by the input unit 110. The controller 130 may reconstruct the test current It flowing through the three-phase AC power line in consideration of the installation information based on the information of the secondary current. The reconstructed test current (It) is installed information such as phase, polarity direction, current ratio with current transformer 20, and angular displacement of transformer 41 included in the monitoring target 40, rated voltages of the primary and secondary sides. It is reconstructed in consideration of. The controller 130 transmits a signal for visualizing and displaying the reconstructed test current It in a vector diagram to the display unit 140.

In addition, the controller 130 estimates the test current It flowing in each phase of the three-phase AC power line based on the installation information, and displays the display unit 140 to display the expected test current It in a vector diagram. More control. The control unit 130 is not based on the information of the secondary current provided by the measurement unit 120, the test power supply 160 is connected between the R phase and the S phase, the angular displacement of the monitoring target 40, the primary side And the test current It by estimating the test current It flowing through the three-phase AC power line based on the installation information such as the secondary side rated voltage.

The display unit 140 visually displays the reconstructed test current It on the display 141 on the basis of the signal received from the controller 130. The vector diagram can be expressed in an angular coordinate system, and the reconstructed test current (It) for each phase (R, S, T, r, s, t) of a three-phase AC power line is configured on one side (P1) and the other side (P2). It can be displayed by dividing by. The display unit 140 may include a display 141 using an LCD, OLED, PDP, or the like.

In addition, the display unit 140 may further display the expected test current It in a vector diagram manner. The display unit 140 displays on the display 141 to compare the reconstructed test current It and the expected test current It so that the vector diagram of the reconstructed test current It is estimated test current It. If different from the vector diagram, the user can visually recognize that the current transformer 20 is not installed correctly.

The communication unit 150 is connected to a wired / wireless network to enable data transmission and reception between a monitoring device and another device (server, etc.). The controller 130 may transmit the test result through the communication unit 150.

The test power supply 160 is connected between two phases selected from the three-phase AC power line of the open side (P1), and applies a single-phase AC test current (It). The test power supply 160 may generate a single-phase AC test current It by receiving a commercial power supply 220V. The test power supply 160 is a portable device that may be configured separately from the monitoring device or may be integrally formed with the monitoring device.

The protection relay installation compliance test apparatus 100 according to an embodiment of the present invention may digitally recognize the secondary current generated by the current transformer 20, perform a protection relay operation, and display the current in a vector diagram. Include digital relays. That is, the digital protection relay that measures the secondary current generated by the current transformer in a digital manner, and performs the inspection method described below, belongs to the inspection apparatus 100 disclosed in accordance with one embodiment of the present invention.

In order to perform the protection relay installation compliance test method according to an embodiment of the present invention, the three-phase AC power line is open on one side (P1) and the other side (P2) short on the basis of the monitoring target 40 The single-phase AC test current It may be configured to be applied between two phases of the open one-phase three-phase AC power line.

As shown in FIG. 1, one side P1 of the monitoring target 40 is open, and the current transformer 20 is installed on the three-phase AC power lines R, S, and T of the open side P1. The other side P2 of the monitoring target 40 is short-circuited, and the current transformer 20 is provided on the three-phase AC power lines r, s and t of the other side P2 shorted. The test power supply 160 is connected to an open point of one side P1 and configured to apply a single-phase AC test current It. The test power supply 160 is connected between two phases of the three phases to input the single phase AC test current It to the R phase and to output the single phase AC test current It to the S phase.

3 is a flowchart illustrating a process of performing a protective relay installation suitability test method according to an embodiment of the present invention, Figure 4 is a detailed circuit diagram for performing the protective relay installation suitability test method according to an embodiment of the present invention.

First, a test circuit necessary to perform the protective relay installation suitability test method according to an embodiment of the present invention is configured (test circuit configuration step, S10). As shown in FIG. 4, the monitoring target 40 may be a power transformer 41 and a generator 42 connected to one side of the power transformer 41. The protective relay 10 may set one generator 42 as the monitoring target 40, and may set the generator 42 and the power transformer 41 together as the monitoring target 40.

As shown in FIG. 4, the first inspection equipment may be installed to check the installation suitability of the first protective relay 10 for monitoring the power transformer 41, and the second protection for monitoring the generator 42. Second inspection equipment may be installed to check the installation suitability of the relay 10. The first monitoring equipment is connected to the current transformers 20a, 20b, and 20c installed in the three-phase AC power lines r, s, and t of one side P1 of the power transformer 41, respectively, It is connected to the current transformers 20j, 20k, and 20l respectively installed on the three-phase AC power lines R, S, and T of the other side P2. The second inspection equipment is connected to the current transformers 20d to 20i respectively installed on the three-phase AC power lines connected to the primary side and the secondary side of the generator 42.

The range necessary for the test operation of the protective relay 10 is separated from the power system 50. That is, in order to separate the three-phase AC power lines (r, s, t) and the power system 50 connected to the other side of the power transformer 41, the breaker 30 is opened and the primary side of the generator 42 is closed. Open the ends of the connected three-phase AC power lines (R, S, T).

In order to construct the test circuit, the ends of the three-phase AC power lines r, s, and t of the other side P2 of the transformer 41 are shorted, and the three-phase AC power line of the other side P1 of the transformer 41 ( The test power supply 160 is connected to two phases (R, S) among R, S, and T. The primary side of the two phases to which the test power supply 160 is to be applied among the primary nodes n4 to n6 and the secondary nodes n1 to n3 of the generator 42 to which the generator 42 and the three-phase AC power line are connected. And the secondary node are connected to each other, and the generator 42 is separated from the three-phase AC power line, thereby bypassing the generator 42. As shown in FIG. 4, nodes n1 and n4 are connected, and nodes n2 and n5 are connected to bypass the test current It to the generator 42. At this time, the circuit may be configured to further connect the nodes n3 and n6 of the phase where the test power supply 160 is not connected. Bypassing the generator 42, the circuit structure for monitoring the installation suitability of the protective relay 10 for monitoring the power transformer 41 can be shown as shown in FIG.

Next, information about the circuit structure configured to check the installation suitability is input through the input unit 110 (installation information input step, S20). When all the installation information is input, the test power supply 160 is operated to apply the single-phase AC test current It (test current application step, S30).

FIG. 5 is a circuit diagram illustrating a current flow when a test current It is applied to R phase and S phase according to an embodiment of the present invention.

In FIG. 5, the power transformer 41 is a Dyn11 method, which is a standard connection. For convenience of explanation, it is assumed that the winding ratio is 1: 1, and the size of the test current It applied by the test power supply 160 is 1PU. Indicates.

When the test current (It) flows in the R phase and the S phase, the current flowing through the three-phase power transformer 41 is tested according to Kirchhoff's Current Law (KCL) with a forward 2 / 3PU size test on the RS phase winding. The current It, the test current It of the reverse 1 / 3PU size flows through the ST phase winding, and the test current It of the reverse 1 / 3PU size flows through the TS phase winding.

Depending on the law of energy conservation and the characteristics of the photosensitive transformer 41, the test current (It) of the forward 2 / 3PU size is in the r phase, the test current (It) of the reverse 1 / 3PU size is in the s phase, and the reverse 1 / 3PU size is in the t phase. The test current It flows and the sum of the test current It becomes 0 at the point where the three phases r, s and t are shorted.

When the test current It is applied, an expected step S80 of predicting the test current It flowing in each phase of the three-phase AC power line in the state where the current transformer 20 is normally installed, based on the installation information, and the expected An expected result display step S90 of visually indicating the test current It in a vector diagram manner may be performed.

The control unit 130, the test power supply 160 is connected between the R phase and the S phase, a single-phase AC test current It of 1PU size is input to the R phase and output as the S phase, the power transformer 41 of the The installation information such as the angular displacement Dyn11 and the winding ratio is provided from the input unit 110, and the test current It flowing through the R phase can be estimated through calculation based on the installation information. Similarly, the test current It flowing in each phase can be estimated based on the said installation information.

The controller 130 may visualize the expected test current It in a vector diagram. The controller 130 may transmit a signal controlling the display unit 140 to the display unit 140 to represent the expected test current It associated with each phase in a vector diagram. The first expected vector diagram PVD1 of the primary side is the expected test current It of phase R with 1 PU size and 0 degree angle, and the expected test current It with phase 1 S and 180 degree angle It. ), The expected test current (It) of T phase of size 0PU can be indicated. The second expected vector diagram PVD2 on the secondary side is the expected test current (It) of r phase with size 2 / 3PU and angle of 180 degrees, the expected phase of phase s with size 1 / 3PU and angle of 0 degree. It is possible to display the test current (It), the expected test current (It) on t phase whose magnitude is 1 / 3PU and the angle is 0 degrees.

The display unit 140 estimates the test current It with respect to the three phases R, S, and T of the primary side of the transformer 41 on the display 141 based on the signal transmitted from the controller 130. Second expected vector diagram PVD2 showing the expected test current It with respect to the three phases r, s, t of the secondary side of the transformer 41 Can be displayed.

On the other hand, when the test current (It) is applied, the current to generate the information of the secondary current by measuring the secondary current generated by the current transformer 20 installed on each phase of the three-phase AC power line connected to the monitoring target 40 Information generation step (S40), reconstruction step (S50) for reconstructing the test current (It) flowing in each phase of the three-phase AC power line based on the information of the secondary current, the reconstructed test current (It) vector It is possible to perform the test result display step (S60) that is shown visually in a diagram manner.

The current transformer 20j for measuring the test current It flowing in R produces a secondary current Isj in accordance with the test current It flowing in R. The measuring unit 120 of the inspection apparatus 100 measures the secondary current Isj generated by the current transformer 20j to generate information of the secondary current Isj regarding the R phase.

Similarly, the current transformers 20k, 20l, 20a, 20b, and 20c for measuring the test current It flowing through the S phase, the T phase, the r phase, the s phase, and the t phase are secondary to each phase. The currents Isk, Isl, Isa, Isb, and Isc are generated, and the measuring unit 120 of the inspection apparatus 100 generates the secondary currents Isk, Isl, Isa, Isb, and Isc generated by the current transformers 20. The measurement generates information on secondary currents (Isk, Isl, Isa, Isb, Isc) for each phase. Finally, the measuring unit 120 of the inspection apparatus 100 may generate the information of the six secondary currents (Isj, Isk, Isl, Isa, Isb, Isc) related to each phase and provide it to the controller 130. have.

The controller 130 may reconstruct the test current It flowing through each phase in consideration of the information of the secondary current provided from the measurement unit 120 and the installation information provided from the input unit 110. The controller 130 receives the polarity direction and the current ratio of the current transformer 20j installed on the R through the installation information, and receives the size, phase, and direction information of the secondary current Isj from the measurement unit 120. , It is possible to reconstruct the test current It flowing in R phase. Similarly, the controller 130 may also reconstruct the test current It flowing through the S phase, the T phase, the r phase, the s phase, and the t phase.

The controller 130 may transmit a signal for visualizing and displaying the reconstructed test current It in a vector diagram manner to the display unit 140. The vector diagram can represent the reconstructed test current (It) using the polar coordinate system.

FIG. 6 is a diagram illustrating a vector diagram displayed on the display 141 of the display unit 140 of the test apparatus 100 in the case of FIG. 5.

As shown in FIG. 6, the display unit 140 may display the expected test current It in a vector diagram based on the signal received from the controller 130, and reconstruct the test current It reconstructed. Can be displayed as a diagram.

The display 141 of the display unit 140 may include a first expected vector diagram PVD1 representing an expected test current It of a primary side, a second representing an expected test current It of a secondary side. 2 The first vector reconstruction vector diagram RVD1 representing the reconstructed test current It of the primary side, the second vector reconstructed test current It of the Secondary side 2 reconstruction vector diagram (RVD2) can be displayed (reconstructed test current visualization step (S60) and the expected test current visualization step (S90)).

The user compares the vector diagrams RVD1 and RVD2 of the reconstructed test current It visually displayed on the display unit 140 of the inspection apparatus 100 with the vector diagrams PVD1 and PVD2 of the expected test current It. Thus, it may be determined whether the current transformer 20 is correctly installed on each phase of the three-phase AC power line connected to the monitoring target 40. The magnitude and direction of the test current It appearing in the first expected vector diagram and the first reconstruction vector diagram are the same, and the magnitude and direction of the test current It appearing in the second expected vector diagram and the second reconstruction vector diagram are the same. Therefore, it can be seen that the current transformer 20 is correctly installed.

In addition, the current information generation step (S40), the test current reconstruction step (S50), the reconstructed test current visualization step (S60), the test current prediction step (S80), the expected test current visualization step (S90), the 3 The single phase AC test current It may be applied between the other phase T of the phase AC power line and one phase S of the selected two phases R and S, and may be further performed at least once.

When the test power supply 160 is connected between the R phase and the S phase and the inspection is performed, the installation current of the current transformer 20l installed in the T phase cannot be determined because the test current It does not flow in the T phase. Therefore, the connection of the test power supply 160 is changed so as to connect the phase T which is not connected to the test power supply 160 and the other phase S (test power connection change step, S70).

When the connection of the test power supply 160 is changed, information about the circuit structure configured to check the installation suitability and the connection structure of the changed test power supply 160 is input through the input unit 110 (installation information input step, S20). . When all the installation information is input, the test power supply 160 is operated to apply the single-phase AC test current It (test current application step, S30).

FIG. 7 is a circuit diagram illustrating a current flow when a test current It is applied to S phase and T phase according to an embodiment of the present invention, and FIG. 8 is a display unit of the inspection apparatus 100 in the case of FIG. A diagram showing a vector diagram displayed on the display 141 of 140.

As shown in FIG. 7, when the test power supply 160 is applied, the test current It of the reverse 1 / 3PU size is applied to the RS phase winding, the test current It is the size of the forward 2 / 3PU size, TS phase in the ST phase winding. Test current It of magnitude 1 / 3PU flows through the winding, and according to the energy conservation law and the characteristics of the photosensitive transformer 41, test current It of magnitude 1 / 3PU is reversed in phase r, and positive 2 in phase s. Test current (It) of size / 3PU, test current (It) of reverse 1 / 3PU size flows in t phase, and test current (It) at the point where three phases (r, s, t) are shorted The sum is zero.

As described above with reference to FIGS. 5 and 6, based on the installation information, an expected step S80 of estimating a test current It flowing through each phase of the three-phase AC power line in the state where the current transformer 20 is normally installed, And a secondary display generated by the current transformer 20 installed in each phase of the three-phase AC power line connected to the monitoring target 40, in step S90 of visually representing the expected test current It in a vector diagram manner. Current information generation step (S40) of measuring the current to generate the information of the secondary current, reconstruction step of reconstructing the test current (It) flowing in each phase of the three-phase AC power line based on the information of the secondary current In operation S50, a test result display step S60 of visually representing the reconstructed test current It in a vector diagram manner may be performed. Details are as described above.

Accordingly, as shown in FIG. 8, the display 141 of the display unit 140 has a first expected vector diagram PVD1, which represents the expected test current It of the primary side, of the secondary side. Of the second expected vector diagram PVD2 representing the expected test current It, the first reconstructed vector diagram RVD1 and the secondary side representing the reconstructed test current It of the primary side A second reconstruction vector diagram RVD2 representing the reconstructed test current It can be displayed (reconstructed test current visualization step S60 and expected test current visualization step S90).

The user compares the vector diagrams RVD1 and RVD2 of the reconstructed test current It visually displayed on the display unit 140 of the inspection apparatus 100 with the vector diagrams PVD1 and PVD2 of the expected test current It. Thus, it may be determined whether the current transformer 20 is correctly installed on each phase of the three-phase AC power line connected to the monitoring target 40. The magnitude and direction of the test current It appearing in the first expected vector diagram and the first reconstruction vector diagram are the same, and the magnitude and direction of the test current It appearing in the second expected vector diagram and the second reconstruction vector diagram are the same. Therefore, it can be seen that the current transformer 20 is correctly installed.

FIG. 9 is a circuit diagram illustrating a current flow when a test current It is applied to the S phase and the T phase according to an embodiment of the present invention, and the current transformer 20 is in a miswiring state. FIG. In the case of Figure 1 is a diagram showing a vector diagram displayed on the display 141 of the display unit 140 of the inspection apparatus 100.

FIG. 9 shows a case in which the polarity direction of the current transformer 20c installed on t is incorrectly installed in the circuit diagram shown in FIG. When any one of the current transformers 20 is miswired as described above, the predicted test current It based on the installation information input by the user is displayed in a correct state as shown in the second expected vector diagram.

In contrast, the test current It reconstructed based on the information of the secondary current generated by the current transformer 20c according to the test current It actually flowing on t is as shown in the second reconstruction vector diagram of FIG. 10. Similarly, the size is shown as 1 / 3PU and the angle is 180 degrees.

Therefore, as soon as the user compares the predicted vector diagrams PVD1 and PVD2 displayed on the display unit 140 of the inspection apparatus 100 with the reconstruction vector diagrams RVD1 and RVD2, the installation of the current transformer 20c installed on t is incorrect. It can be recognized.

Conventionally, in order to determine the installation suitability of the protective relay and the current transformer, the installation suitability was judged by separating the three-phase AC power line and the power system and applying a three-phase AC test current to the three-phase AC power line. However, this method requires a separate three-phase alternator, variable transformer, and test transformer for applying the test current to apply the three-phase AC test current suitable for the rated voltage of the monitored object. It requires cost, time and professional effort.

In addition, in this method, the phase angle and magnitude of the secondary current generated by the current transformer should be calculated in consideration of the angular displacement of the power transformer included in the monitoring target, and the current ratio of the current transformer itself should be taken into consideration. Complex calculations are required.

On the other hand, the protective relay installation suitability test method and the inspection apparatus 100 according to the embodiment of the present invention described above flows from the secondary current generated by the current transformer 20 installed in the three-phase AC power line to the three-phase AC power line. By reconstructing the current and predicting the test current It with the current transformer 20 installed correctly and visually displaying it using a vector diagram, the user can quickly and accurately confirm the installation suitability of the protective relay 10.

In addition, the protective relay installation suitability test method and test apparatus 100 according to an embodiment of the present invention described above can use a portable single-phase current source as the test power supply 160, the test when the correct connection in the test operation process Since it is possible to visually compare the vector diagram of the current It and the vector diagram of the test current It based on the measured value of the actual current transformer 20, simplifying and inspecting the equipment necessary for the installation suitability check of the protective relay 10. Save time and money.

The protective relay installation conformity test method according to the embodiment of the present invention described above may be provided by being implemented in a manner in which a program consisting of a set of instructions for implementing the same is recorded in a computer-readable recording medium. .

Program instructions recorded on a computer readable recording medium may be those specially designed and constructed for the present invention, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of such computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and floptical disks. Magneto-optical media, and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, USB memory, and the like.

Although the present invention has been described in detail through specific examples, it is intended to describe the present invention in detail, and the present invention is not limited thereto, and should be understood by those skilled in the art within the technical spirit of the present invention. It is obvious that the modifications and improvements are possible.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be apparent from the appended claims.

100: inspection device
110: input unit
120: measuring unit
130: control unit
140: display unit
141: display
150: communication unit
160: test power
10: protective relay
20: current transformer
30: breaker
40: watch target
41: transformer
42: generator
50: power system

Claims (8)

A measuring unit configured to measure secondary currents generated by current transformers installed on respective phases of the three-phase AC power lines connected to the monitoring object and generate information of the secondary currents;
A controller configured to reconstruct a test current flowing in each phase of the three-phase AC power line based on the information of the secondary current and to control the display unit to display the reconstructed test current in a vector diagram;
And a display unit for visually representing the reconstructed test current in a vector diagram manner.
The three phase AC power line
The one side is opened and the other side is short-circuited based on the monitoring target, and a single phase AC test current is applied between two phases of the open one-phase three-phase AC power line. The method according to claim 1,
Further comprising an input unit for receiving the installation information of the monitoring target and the current transformer,
The control unit
On the basis of the installation information, the display unit is further configured to estimate a test current flowing in each phase of the three-phase AC power line in which the current transformer is normally installed, and display the expected test current in a vector diagram.
The display unit
A protective relay installation compliance tester further visually representing the expected test current in a vector diagram manner. The method according to claim 1,
And a test power supply connected between two phases of the three-phase AC power line to supply a single-phase AC test current. Generating current information by measuring secondary current generated by a current transformer installed in each phase of a three-phase AC power line connected to a monitoring target;
A reconstruction step of reconstructing a test current flowing in each phase of the three-phase AC power line based on the information of the secondary current;
And a test result display step of visually representing the reconstructed test current in a vector diagram manner.
The three phase AC power line
The one side is opened and the other side is short-circuited based on the monitoring target, and a single phase AC test current is applied between two phases of the open one-phase three-phase AC power line. The method according to claim 4,
An expected step of estimating a test current flowing in each phase of the three-phase AC power line in the state where the current transformer is normally installed, based on the monitoring target and the installation information of the current transformer;
The protective relay installation suitability test method further comprising the step of displaying the expected result visually representing the expected test current in a vector diagram. The method according to claim 4,
The current information generation step, reconstruction step, test result display step
And applying the single-phase AC test current between the other one of the three-phase AC power lines and one of the two phases, and performing at least one or more times. The method according to claim 4,
The current information generation step, reconstruction step, test result display step
A protective relay installation compliance test, performed in a digital protective relay with vector diagram display. A computer-readable recording medium in which a program for performing the protective relay installation compliance test method according to any one of claims 4 to 7 is described.

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