JP2000184601A - System interconnection power unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a short circuit current from flowing in an electric power system from a system interconnection power unit when short circuit is generated in the system. SOLUTION: A DC power source 2, an electric converter 3 converting DC power from the DC power source 2 to AC power, and a system interconnection protective device 4 which detects abnormality of an electric power system 6 connected with the electric converter and generates a signal for cutting off the output of the converter, are installed. The protective device 4 consists of a system abnormality detecting relay 4a which has a previously set specific operation time limit and operates, and a high speed short circuit detecting relay 4b which detects at a high speed a short circuit accident of the connected electric power system and operates. A high speed cutting off means is installed which breaks the output of the converter 3 at a high speed when the relay 4b operates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a photovoltaic power generator,
The present invention relates to a grid-connected power supply device used in connection with a power system such as a fuel cell power generation device and a power storage device using a secondary battery.

[0002]

2. Description of the Related Art FIG. 6 shows a configuration diagram of a conventional grid-connected power supply device linked to a power system. The grid-connected power supply 1
The DC power source 2 includes a DC power source 2 such as a secondary battery, a solar cell, or a fuel cell, a power conversion device 3 and a grid connection protection device 4. The DC power generated by the DC power source 2 is converted into AC power by the power conversion device 3. , Synchronized with the voltage of the power system 6
And supplies power to the load 5. The grid interconnection protection device 4 (grid abnormality detection relay 4a) detects an abnormality of a grid system to be connected and protects a grid interconnection power supply device such as a power system or a photovoltaic power generation system. (OVR), under-voltage relay (UVR), over-frequency relay (OFR), under-frequency relay (UFR), and islanding detection relay. Each relay has a system abnormality detector and a timer. Here, each relay is set to operate with a predetermined detection level and a time limit in order to prevent malfunction. In other words, each relay constantly monitors the power system, measures the time with a timer when an abnormality greater than the detection level is detected by the system abnormality detector, and when the abnormality continues for longer than the set time limit, sends a cutoff signal to the power converter 3. To stop the output of the power converter 3. In general, the power conversion device 3 for system interconnection controls the output current to a constant current. If there is no voltage maintenance function in the case of a power failure in the interconnected power system, the voltage will be in accordance with the system impedance and the output current. After a certain period of time, an undervoltage relay (UVR), an islanding detection relay, etc. Works, and the output of the power converter 3 stops.

[0003]

However, even when a short circuit accident (point A in FIG. 6) occurs in the power system to be connected, the system interconnection protection device operates in the same manner as described above.
As shown in FIG. 7, the system abnormality detector immediately detects a power failure, but since the time limit tb is set, the system interconnection power supply device 1 supplies power until the system abnormality detection relay operates (tb). The system will be supplied with the short-circuit current Ib, which will increase the short-circuit current at the short-circuit fault point (Ia + Ib). There is a circuit breaker (for example, 7a) that cannot interrupt the increased short-circuit current in the power system to be interconnected,
If a short circuit accident (point A) occurs below the circuit breaker 7a, the accident point cannot be normally separated, and the short circuit accident may spread to other customers. When a grid-connected power supply such as a photovoltaic power generator is used in connection with a power system as described above, the short-circuit capacity of the connected grid is 1.0 to 1 times the capacity of the linked power supply. The short-circuit capacity will increase by a factor of five. In this case, if any of the circuit breakers installed in the higher-level power system that is connected has insufficient breaking capacity, it is not possible to connect the grid-connected power supply to that power system. This will be a major issue in the effective use of new energy such as photovoltaic power generation, and in the introduction and diffusion of power load leveling equipment utilizing new batteries.

[0004] It is an object of the present invention to provide a grid-connected power supply that minimizes a short-circuit current from flowing into a power system when a short-circuit occurs in the power system.

[0005]

The present invention has solved the above-mentioned problems by the following means.

According to a first aspect of the present invention, there is provided a DC power source, a power converter for converting DC power from the DC power source into AC power, and a power system interconnected with the power converter. A system interconnection power supply device comprising: a system interconnection protection device that detects an abnormality and issues a signal for shutting off the output of the power conversion device, wherein the system interconnection protection device has a predetermined operation time limit set in advance. It consists of an operating system abnormality detection relay and a high-speed short-circuit detection relay that operates by detecting a short-circuit accident in the interconnected power system at high speed. It is characterized by having a high-speed shut-off means for shutting off at the same time, thereby having the following operation. That is, in addition to the protection against the normal power system abnormality, the system interconnection power supply device has a high-speed short-circuit detection relay and a high-speed cut-off means that operate by detecting a short-circuit accident in the power system at a high speed. To prevent the short circuit current from flowing out to the power system.

According to a second aspect of the present invention, there is provided the grid-connected power supply according to the first aspect, wherein after the high-speed cut-off means operates, the abnormal state of the power system connected to the power system becomes normal. It is characterized in that the high-speed cutoff means is released after a predetermined operation time limit from the time of recovery, and the power converter and the power system are interconnected, thereby having the following operation. That is, when the system voltage recovers to normal after the high-speed cut-off means operates, the operation of the grid-connected power supply is automatically restarted. The suspension period of the device can be shortened.

According to a third aspect of the present invention, there is provided the grid-connected power supply according to the first or second aspect, wherein the high-speed cutoff means gate-blocks a switching element of the power conversion device or a semiconductor switch. It is characterized in that it is a means to cut off the high-speed circuit breaker consisting of
This has the following effect. In other words, the switching element of the power conversion device is gate-blocked, or the high-speed circuit breaker formed of a semiconductor switch is cut off, so that the power conversion device is cut off at high speed and the short circuit current is prevented from flowing out to the system as much as possible. be able to.

According to a fourth aspect of the present invention, there is provided the grid-connected power supply according to the first or second aspect, wherein the output of the power converter is output by high-speed cutoff means that gate-blocks a switching element of the power converter. After the high-speed cut-off, and after the high-speed cut-off, the circuit breaker inside the power converter or the circuit breaker provided between the interconnection point between the power converter and the power system is cut off, Releases the high-speed cutoff means that gate blocks the switching elements, performs independent operation, and supplies power to a specific load installed between the cutoff circuit breaker and the power conversion unit of the power conversion device. This has the following effect. That is, by blocking the switching element of the power converter at a high speed, it is possible to cut off at a high speed to prevent a short circuit current from flowing out to the system as much as possible, and to confirm that the power converter is disconnected from the system, Therefore, power can be supplied from a DC power source such as a solar cell to a specific load.

According to a fifth aspect of the present invention, there is provided a grid-connected power supply according to the first or second aspect, wherein the high-speed cut-off means for cutting off a high-speed circuit breaker comprising a semiconductor switch is used for power conversion. The output is cut off at a high speed, and the power converter performs the self-sustaining operation following or at the same time as the high-speed cutoff. Which has the following effects. In other words, a high-speed circuit breaker consisting of a semiconductor switch prevents the short-circuit current from flowing out to the power system by shutting down at a high speed as much as possible. The power can be supplied to the load from a DC power source such as a solar cell without an instantaneous interruption.

According to a sixth aspect of the present invention, there is provided a system interconnection power supply according to any one of the first to third aspects, wherein the power supply is branched from a connection between a DC power source and a power converter. , A preset specific load is connected via the power converter for specific load, and the output of the power converter is cut off at high speed by the high-speed cut-off means. To supply power to a specific load via the device, or to start operation of the power converter for a specific load after high-speed interruption, and to supply power from the DC power source to the specific load. This has the following effects. In other words, when a short-circuit accident occurs in the interconnected power system, the output of the power converter is shut off at high speed by the high-speed shutoff means, and power is supplied from the DC power source to the specific load without momentary interruption. Or, or after a high-speed cut-off, it is possible to newly supply power to a specific load from a DC power source.
Even in the event of a short-circuit accident, it is possible to prevent a short-circuit current from flowing out to the power system as much as possible and to continuously supply power to a specific load.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

First Embodiment FIG. 1 is a diagram showing a configuration of a grid-connected power supply according to a first embodiment of the present invention. Here, the system interconnection power supply device 1 includes a DC power source 2, a power conversion device 3, and a system interconnection protection device 4, and supplies electric power to a load 5 in connection with a system 6.

As the DC power source 2, a DC power source such as a secondary battery, a solar cell, or a fuel cell is used. AC power such as wind power is generated. Includes a power supply that converts to AC.

The power converter 3 has various functions depending on the application. Basically, the power converter 3 converts DC power generated from a DC power source into AC power and synchronizes with the grid to operate the grid. I do. When used in a secondary battery power storage system, the secondary battery is usually charged from the night grid,
It has a bidirectional inverter function that discharges as needed during the day. In the case of a photovoltaic power generation system, the power conversion device 3 has a maximum power point tracking control function because the output of the solar cell fluctuates every moment depending on the amount of solar radiation.

The system interconnection protection device 4 comprises a system abnormality detection relay 4a and a high-speed short-circuit detection relay 4b. The normal system abnormality detection relay 4a is stipulated in the system interconnection guideline so that no problem occurs when a distributed power supply is connected to the system and is generally used.
R, OFR, UFR and islanding detection relay. Although FIG. 1 shows a set of system abnormality detection relays including an abnormality detector and a timer as a representative, a predetermined operation level and operation time for each of these relays is determined by the characteristics of the system to be interconnected. It can be set according to.

The high-speed short-circuit detection relay 4b detects a short-circuit accident of the interconnected system at a high speed, operates instantaneously without a time limit, and gives a signal to the high-speed cut-off means. As a method of detecting a short circuit accident, for example, a method of detecting a sudden voltage drop at an interconnection point due to occurrence of a short circuit accident in a higher system or a method of detecting imbalance of three-phase voltages at an interconnection point is used. However, other detection methods may be used.
The setting of the voltage drop level (operating voltage value) differs depending on each system, but is set to be much smaller than the operating voltage setting level in the undervoltage relay (UVR), and set to a level that does not operate with normal voltage fluctuations. The setting of the voltage drop level is set according to the characteristics of the system, the set level of the system abnormality detection relay, and the like.

The system interconnection protection device 4 needs to constantly observe information on the power system to detect the occurrence of an abnormality in the power system to be interconnected and the fact that the system has returned to the normal state. From the point where the output of the interconnection power supply is cut off, information on the voltage and current of the power system connected from the system side is input.

The high-speed interrupting means needs to be able to shut off earlier than the circuit breaker 7a at the short-circuit fault point starts the interrupting operation, and the current mechanical circuit breaker is insufficient in speed. In order to cut off the power, a means using a gate block of a switching element (not shown) in the power converter 3 or a means for cutting off a high-speed circuit breaker using a semiconductor such as a thyristor switch (not shown) is used. In the case where the means using a semiconductor switch is used, the semiconductor switch is provided inside the power converter 3 between the power converter 3a and the electromagnetic circuit breaker 3b or between the power converter 3 and the circuit breaker 7b in the switchboard. Provided.

Next, the operation of the present invention will be described. When the system is normal, the DC power generated from the DC power source 2 such as a solar cell is converted into AC power by the power converter 3 and partly supplied to the load 5. You. Since the detection level and the operation time limit are set so that the system abnormality detection relay 4a does not operate in a normal allowable voltage fluctuation or frequency fluctuation, malfunction can be prevented.
Also, other than short circuit accidents, system abnormalities such as power failures exceed the set detection level and operation time limit, so after a predetermined time,
The shutoff means operates to safely stop the device.

The case where a short circuit accident has occurred will be described in detail with reference to FIG. In FIG. 2, (a) is a voltage waveform of an interconnected system, for example, a voltage waveform at a point B in FIG. 1, and (b) is a voltage waveform of an interconnection point observed by the interconnection protection device 4. The voltage waveform (voltage waveform at point C) is shown, and (c) is the output current waveform of the power converter 3. (D) is the output signal of the system abnormality detector (input of the timer), (e) is the output signal of the system abnormality detection relay 4a, and (f) is the output signal of the high-speed short-circuit detection relay 4b.

If a short-circuit accident occurs in a higher-level power system connected to the system, a sharp drop in the system voltage occurs at points B and C, and the high-speed short-circuit detection relay 4b detects this at high speed and instantaneously detects it. A cutoff signal is sent to the power converter 3. Here, the system abnormality detector also detects the abnormality and sends the output to the timer, but the output as the relay is not output because there is a time limit. The power conversion device 3 receiving the cutoff signal stops the output by instantaneously gate-blocking the switching element. By doing so, it is possible to minimize the supply of a short-circuit current from the grid-connected power supply device 1 to the short-circuit fault point in the event of a short-circuit fault, to prevent an increase in the short-circuit current at the fault point, and to prevent the short-circuit current at the fault point by the circuit breaker 7a. Safe disconnection takes place.

Normally, when a system in which a short-circuit fault has occurred is disconnected from the other system by the short-circuit fault circuit breaker 7a, the other system returns to a normal state. When the system recovers to normal, the stopped operation of the grid-connected power supply 1 may be restarted. In this case, the operation may be restarted manually,
It is better to do the following automatic driving. The high-speed short-circuit detection relay 4b monitors the state of the system even after the output of the power conversion device 3 is cut off by the high-speed cut-off means. The high-speed cutoff means is released, and the power conversion device 3 starts outputting again to supply power to the load in connection with the grid. At this time, the reason for setting the return time ta is to prevent a problem due to malfunction of the system recovery signal.
Is desirably set longer than the time required for the circuit breaker 7a at the short-circuit fault point to operate reliably and to be disconnected from the normal system. Normally, when the system is connected again to the system, the synchronization is performed with the system voltage.

By doing so, the influence of a malfunction in detecting a short-circuit accident can be reduced, and the system interconnection power supply 1 can be operated immediately after the system is restored, so that the device can be used effectively.

In the present embodiment, the grid connection protection device 4 is provided separately from the power conversion device 3, but may be incorporated in the same box as the power conversion device 3, or may be a high-speed short-circuit detection relay 4b. Only the power conversion device 3 may have the system abnormality detection relay 4 a that is installed on a distribution board or the like and has an operation time limit. That is, the form in which the system abnormality detection relay 4a having the operation time limit and the high-speed short-circuit detection relay 4b are installed is not particularly limited.

Second Embodiment FIG. 3 is a diagram showing a configuration of a system interconnection power supply according to a second embodiment of the present invention. The load is divided into a normal load 5a and a specific load 5b such as an emergency load or an important load that cannot be stopped,
The specific load 5b is a circuit breaker 3 inside the power conversion device 3.
b and is branched from between the power converter and connected via a specific load circuit breaker. Further, a breaker trip signal (or a system recovery signal) is transmitted from the high-speed short-circuit detection relay 4 to the circuit breaker 3b. Other configurations are the same as those in FIG.

Next, this operation will be described. The normal state is the same as in the first embodiment. When a short-circuit accident occurs (for example, at point A), the high-speed short-circuit detection relay 4b detects a rapid decrease in the system voltage due to the short-circuit accident, sends a gate block signal to the power converter 3 instantaneously, and trips the circuit breaker. The signal is sent to the circuit breaker 3b inside the power converter 3. The power converter 3 stops the output by instantaneously gate-blocking the switching element. Subsequently, the circuit breaker 3b is also shut off, and the grid-connected power supply 1 is disconnected from the grid. After that, the power conversion device 3 releases the gate block of the switching element, switches to the independent operation mode, performs the independent operation, and supplies power to the specific load 5b. Here, the self-sustained operation refers to an operation state of a device that supplies power to a load without being connected to a power system, and is usually controlled by a constant voltage control method for the power conversion device 3 (independent operation mode). Is performed. On the other hand, when the power conversion device 3 is operated in connection with the grid, the control of the power conversion device 3 (interconnection operation mode) is normally performed by the constant current control method. Switching is performed.

Incidentally, even if a power failure occurs due to a system abnormality other than a short circuit accident, after the system abnormality detection relay 4a shuts off the operation,
It is needless to say that power can be supplied to the specific load 5b in the same manner as described above.

When the system is restored, the high-speed short-circuit detecting relay 4b detects the restoration of the system and sends a system restoration signal to the circuit breaker 3b and the power converter 3 after a predetermined time limit, so that the system 6 is connected to the system interconnection power supply. 1 and are interconnected again. At this time, the power conversion device 3 receives the system recovery signal from the high-speed short-circuit detection relay 4b, stops the self-sustaining operation mode, and switches to the interconnection operation mode to operate. The points to be noted at the time of reconnection are the same as in the first embodiment.

By doing so, it is possible to minimize the supply of a short-circuit current from the system interconnection power supply 1 to the short-circuit fault point at the time of a short-circuit fault, and to protect the important specific load 5b even if the power failure due to the system abnormality continues. In this way, power can be continuously supplied from the system interconnection power supply 1.

Here, in FIG. 3, the circuit breaker 3b inside the power converter 3 is cut off. However, even if the circuit breaker 7b in the distribution board to which the system interconnection power supply 1 is connected is cut off, for example. Often, in this case, the circuit breaker trip signal is
Sent to Also. In this case, the specific load 5b may be branched and connected between the circuit breaker 7b and the system interconnection power supply device 1. Further, the specific load circuit breaker may be provided in the grid-connected power supply device 1 or may be mounted outside. Others are the same as in the first embodiment.

Third Embodiment FIG. 4 is a diagram showing a configuration of a system interconnection power supply according to a third embodiment of the present invention. This is an example in which a thyristor switch 9 is used as high-speed cutoff means, and is provided between the power converter 3 and the circuit breaker 7b. The specific load 5b branches off from between the thyristor switch 9 and the power converter 3, and is connected via a specific load circuit breaker. The high-speed short-circuit detection relay 4b sends a shut-off signal to the thyristor switch 9 and sends an autonomous operation start signal to the power converter 3.
Other configurations are the same as those in FIG.

Next, this operation will be described. Except for a short circuit accident, the operation is the same as that of the first embodiment. When a short-circuit accident occurs (for example, at point A), the high-speed short-circuit detection relay 4b
Detects a rapid drop in system voltage due to a short circuit accident, sends a shutoff signal to the thyristor switch 9 instantaneously, and sends a self-sustained operation start signal to the power converter 3. The thyristor switch 9 cuts off the circuit instantaneously and
To prevent the output of the system from flowing out to the system. Power converter 3
Receives the independent operation start signal, starts the independent operation, and supplies power to the specific load 5b. If the self-sustaining operation is started instantaneously, power can be supplied to the important specific load 5b such as a computer without a momentary interruption, and the self-sustaining operation can be started only when necessary to supply the specific load 5b such as an emergency load. Power can also be supplied. It should be noted that, even when a power failure occurs due to a system abnormality other than a short-circuit accident, the power can be supplied to the specific load 5b in the same manner as described above after the power is cut off by the operation of the system abnormality detection relay 4a.

When the power system recovers, the high-speed short-circuit detection relay 4b detects the recovery of the power system and sends a power recovery signal to the thyristor switch 9 and the power converter 3 after a predetermined time limit, so that the power system 1 and the power system 1 And interconnect again. On this occasion,
The power conversion device 3 receives the system recovery signal from the high-speed short-circuit detection relay 4b, stops the independent operation mode, and switches to the system interconnection mode to operate. The points to be noted at the time of reconnection are the same as in the first embodiment.

By doing so, it is possible to minimize the supply of a short-circuit current from the grid-connected power supply 1 to the short-circuit fault point at the time of a short-circuit fault, and to protect the important specific load 5b even when the power failure due to a system fault continues. In addition, it is also possible to continue to supply power from the system interconnection power supply device 1 without interruption.

Here, the thyristor switch 9 may be installed inside the power converter 3 between the circuit breaker 3b and the power converter. In this case, the specific load 5b is connected between the thyristor switch 9 and the power converter. It is branched and connected from between.

Fourth Embodiment FIG. 5 is a diagram showing a configuration of a system interconnection power supply according to a fourth embodiment of the present invention. A specific load such as an emergency load or an important load that cannot be stopped, and an AC load 5b 'and a DC load 5b''
The AC specific load 5b ′ and the DC specific load 5b ″ are respectively connected to an inverter 8a and a converter 8b.
Power converter 3 via the specific load power converter
And the DC power supply 2. Also, a start signal is sent from the high-speed power failure detection device 4b to the specific load power conversion devices 8a and 8b. Other configurations are the same as those in FIG.

Next, this operation will be described. When the specific loads 5b ′ and 5b ″ are used only in an emergency, when the system is normal, the power converter for specific load including the inverter 8a and the converter 8b is stopped, and the first DC power source 2 As in the embodiment, power is supplied to the normal load 5a in connection with the system 6. When a short-circuit accident occurs (point A), the high-speed short-circuit detection relay 4b detects a rapid decrease in system voltage due to the short-circuit accident, sends a gate block signal to the power converter 3 instantaneously, and converts power for a specific load. An activation signal is sent to the devices 8a and 8b. The power conversion device 3 instantaneously stops output to the system side by instantaneously gate-blocking the switching element. The specific load power converters 8a and 8b start operation and supply power from the DC power source to the specific load.

When the specific load is an important load such as a computer that cannot be powered out, when the system is normal, the grid-connected power supply 1 supplies the important load from the DC power source 2 to the specific load power converters 8a and 8b. The power is supplied to the normal load 5a and the system in connection with the system. When a short-circuit accident occurs, the power converter 3 stops outputting to the system at a high speed in response to a signal from the high-speed short-circuit detection relay 4b, but from the DC power source 2 via the specific load power converters 8a and 8b. The power is continuously supplied to the specific load without interruption. The operation when the system recovers is the same as in the first embodiment. It should be noted that, even when a power failure occurs due to a system abnormality other than a short-circuit accident, the power can be supplied to the specific load 5b in the same manner as described above after the power is cut off by the operation of the system abnormality detection relay 4a.

In this way, even if a short-circuit fault occurs, it is possible to continuously supply power without instantaneous interruption to the specific important load without increasing the short-circuit current at the fault point.

Here, either one of the AC specific load 5b 'and the DC specific load 5b''may be possible. Others are the same as in the first embodiment.

[0042]

As described above, according to the present invention, the following effects can be obtained. According to the first aspect, in addition to protection against a normal system abnormality, the system includes a high-speed short-circuit detection relay that operates by detecting a short-circuit accident of the system at a high speed and a high-speed cutoff unit, so that the system can be connected when a system short-circuit occurs. Since it is possible to prevent a short circuit current from flowing from the power supply device to the system as much as possible, it is possible to prevent a short circuit accident from spreading to other systems, thereby improving the safety of the system. In addition, this allows the grid-connected power supply device to be installed without considering the influence on the short-circuit capacity of the higher-link grid, thereby contributing to the introduction and spread of the grid-connected power supply device using natural energy.

According to the second aspect, even if a short circuit accident occurs in the system, the output of the system interconnection power supply can be cut off at high speed, and it is confirmed that the system has returned to normal. Since the interconnected power supply can be restarted,
In addition to the effect of the first aspect, it is possible to effectively use the grid-connected power supply.

According to the third aspect, since the power conversion device can be shut off at a higher speed, the safety is further improved.

According to the fourth or fifth aspect, the output from the grid-connected power supply device to the grid can be cut off at a higher speed, and power can be supplied to a specific load by independent operation. In addition to the effects of items 1 and 2, it can also be used as an emergency power supply that does not increase the short-circuit capacity, increasing the added value.

According to the sixth aspect, the output from the system interconnection power supply to the system can be cut off at a higher speed, and
Since the power can be continuously supplied to the specific load via the specific load power converter without instantaneous interruption, in addition to the effect of claim 1, the specific load uninterruptible power supply does not increase the short-circuit capacity. Can also be used to increase added value.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a system interconnection power supply device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an operation of the grid-connected power supply according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration of a system interconnection power supply according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a configuration of a system interconnection power supply device according to a third embodiment of the present invention.

FIG. 5 is a diagram illustrating a configuration of a system interconnection power supply device according to a fourth embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a conventional grid-connected power supply device.

FIG. 7 is a diagram illustrating an operation of a conventional grid-connected power supply device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Grid connection power supply 2 DC power source 3 Power converter 3a Power converter 3b Circuit breaker inside power converter 4 Grid connection protection device 4a System abnormality detection relay having operation time limit 4b High-speed short-circuit detection relay 5 Load 5a Normal load 5b Specific load 5b'AC specific load 5b''DC specific load 6 Power system 7a Short circuit fault circuit breaker 7b External circuit breaker to which grid-connected power supply device is connected 8a AC specific load inverter 8b DC Converter for specific load 9 Thyristor switch Ia Short circuit current from upper system Ib Short circuit current from system interconnection power supply ta Time from system restoration detection to reconnection of system interconnection power supply tb From system interconnection power supply Time when the short-circuit current flows

Continuation of front page (72) Inventor Taihei Kikuoka 3-3-22 Nakanoshima, Kita-ku, Osaka-shi, Osaka Kansai Electric Power Co., Inc. (72) Inventor Hideji Sakashita 2-1-1, Tagawa, Yodogawa-ku, Osaka-shi, Osaka Shares (72) Inventor Koji Okuda 2-1-1, Tagawa, Yodogawa-ku, Osaka-shi, Osaka F-term Co., Ltd. F term (reference) 5G066 HA06 HA10 HA11 HA13 HA13 HB04

Claims (6)

[Claims] A DC power source, a power conversion device for converting DC power from the DC power source into AC power, and a power conversion device that detects an abnormality in a power system interconnected with the power conversion device and detects the abnormality. A system interconnection power supply device, comprising: a system interconnection protection device that issues a signal that shuts off the output of the device; and a system abnormality detection relay that operates with a predetermined operation time limit that is set in advance. And a high-speed short-circuit detection relay that operates by detecting a short-circuit accident of the interconnected power system at a high speed, and when the high-speed short-circuit detection relay operates, shuts off the output of the power converter at high speed. A system interconnection power supply device having high-speed cutoff means. 2. The grid-connected power supply according to claim 1, wherein after the high-speed cut-off means operates, a predetermined value is set from a point in time when an abnormal state of the connected power system is restored to a normal state. A system interconnection power supply, wherein the high-speed cutoff means is released after a predetermined operation time limit, and the power converter and the power system are interconnected. 3. The grid-connected power supply device according to claim 1, wherein the high-speed cutoff unit cuts off a high-speed circuit breaker including a gate block unit or a semiconductor switch of the power conversion device. A grid-connected power supply device. 4. The grid-connected power supply device according to claim 1, wherein an output of the power conversion device is cut off at high speed by the high-speed cutoff means that gate-blocks a switching element of the power conversion device. After the high-speed cutoff, after the circuit breaker inside the power converter or the circuit breaker provided between the interconnection point of the power converter and the power system is cut off, the power converter is switched. Releasing the high-speed cutoff means for gate-blocking the element and performing an autonomous operation to supply power to a specific load installed between the cutoff circuit breaker and a power conversion unit of the power conversion device. Grid-connected power supply. 5. The system interconnection power supply device according to claim 1, wherein an output of the power converter is cut off at high speed by the high-speed cut-off means for cutting off a high-speed circuit breaker comprising a semiconductor switch. Following or simultaneously with the high-speed cut-off, the power converter performs an independent operation and supplies power to a specific load installed between a high-speed circuit breaker including the semiconductor switch and a power converter of the power converter. A grid-connected power supply device characterized by the above-mentioned. 6. The grid-connected power supply device according to claim 1, wherein a specific load preset from a connection portion between the DC power source and the power conversion device is set. Is connected via the power converter for specific load, and the output of the power converter is cut off at a high speed by the high-speed cutoff means. Through the supply of power to the specific load, or after the high-speed cutoff, start the operation of the power converter for specific load, to supply power from the DC power source to the specific load. A grid-connected power supply characterized by supplying.