JP2002315175A - Protective relay system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of a protective relay system comprising a plurality of protective relays having an automatic monitoring function that individual protective relays are monitored automatically and a protective relay is locked upon detection of a failure but a decision may be made that a protective relay has failed even when the cause of the failure is not present on the protective relay side but depends on a fault on the power system side and the relay may be locked unnecessarily, and the protective function of the system may be lost entirely when all protective relays are locked due to a cause on the power system side. SOLUTION: Failure detection data of a plurality of protective relays is transmitted through a communication network to a central decision unit where a decision is made whether a fault has occurred on the power system side or a protective relay has failed based on the failure detection time, the failure detection time interval or the failure detection content of failure detection data of respective protective relays. When a decision is made that a fault has occurred on the power system side, unnecessary locking of the protective relays is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protection relay system in a power system having an automatic monitoring function and a function of locking a protection relay device when a failure is detected.

[0002]

2. Description of the Related Art Automatic monitoring is an important function for a protection relay device such as a protection control relay device or a system stabilization device in a power system. The normal operation of the protection relay device is that it does not operate when the power system is in a normal state, but only when an accident occurs in the system. Therefore, if a failure occurs in the protection relay device itself, it cannot operate when operation should be performed as in the case of a system failure, or malfunctions when the system should not operate as in a normal state. That may occur. This must be avoided in view of the operational reliability of the protection relay system. In general, the basic concept of a protection relay device is to detect a failure of the protection relay device itself by automatic monitoring, and to lock the protection relay device itself appropriately when a failure is found.

There are two modes of failure of the protection relay device. That is, a mode in which the protection relay device malfunctions,
On the contrary, this is a mode in which a malfunction does not occur. It is relatively easy to detect a mode that causes a malfunction. This can be achieved by always monitoring the output of the protection relay device and issuing an alarm or the like when the output has continued for a predetermined time or more. That is, since an accident that occurs in the power system does not last for a long time, if the protection relay device continues operating output for a longer time than the maximum value of the duration of the accident that can occur in the power system, the protection relay device side Is determined to be a malfunction due to the failure of the device. This failure detection method is generally referred to as “constant monitoring”.

On the other hand, it is relatively difficult to detect a malfunction due to a malfunction because a malfunction phenomenon does not appear during normal operation. "Automatic inspection" is required to detect this malfunction. For example, the protection function is locked once a week, an AC input similar to that of a system fault is imitated, and it is checked whether the protection relay device operates properly. By such automatic monitoring including “always monitoring” and “automatic inspection”, the protection relay device has conventionally established high operation reliability.

FIG. 12 shows a general configuration of a protection relay device (digital relay device) employing a microcomputer. In the figure, 22 is a circuit breaker connected to a power system (transmission line), 25 is an input converter, and the PT (transformer) 32 is used to measure the voltage of the power system to which the circuit breaker is connected, and CT (current). Current transformers) 23, and converts their system electric quantities into signals of an appropriate magnitude. 26 is A / D
The conversion unit sequentially converts the plurality of analog signals from the input converter 25 into digital signals. Reference numeral 27 denotes a memory unit for storing digital data of system voltage and system current output from the A / D converter 26. 28 is an arithmetic unit (MPU)
It usually consists of a microcomputer. Reference numeral 29 denotes a memory (ROM) for storing an operation program.
Reference numeral 30 denotes an input interface (D / I) for taking in external conditions, and the set value of the protection relay device is also taken in from this input interface. Reference numeral 31 denotes an output interface (D / O), and a trip command to the circuit breaker 22 installed in the power system is also performed through the output interface 31.

[0006]

The protection relay device determines the operation based on the amount of electricity taken from the power system, and determines the analog input monitoring such as the balance monitoring and the zero-phase monitoring. Since this determination method is already known, detailed description is omitted. In addition, a breaker (CB) that is taken in each device to make an operation determination based on the system state
Input circuit monitoring is also performed for equipment conditions such as a disconnector (LS) and a disconnector (LS). FIG. 13 shows the concept from the detection of a monitoring failure to the lock of a device. 11 is a schematic diagram of an automatic monitoring process (software) of the individual protection relay devices 10 constituting the protection relay system. The failure detection unit 11A detects various failures by automatic monitoring, and a failure determination timer 1
After the time is determined in 1B, the failure is determined by the failure determination unit 11C, the time data at the time of the failure detection is stored together with the content of the failure in the storage unit 11D, and the device lock unit 16 locks the protection relay device. Things. In the protection relay system, the presence / absence of device lock is determined for each protection relay device 10.For example, even if the cause of the failure is not on the protection relay device side and depends on the power system side, it is determined that the device is defective. In some cases, the device may be unnecessarily locked.

When a protection relay device having an automatic monitoring function and locking the device when a failure is detected detects a failure unnecessarily due to a factor on the power system side, the entire protection relay system of the same power system similarly operates. There is a possibility that a failure is detected, all the protection relay devices are locked, and all the protection functions of the power system are lost. This has no meaning even if measures are taken to improve system reliability, such as multi-system protection relay devices or a dual configuration of main protection and back-up protection. Will be missing.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. Even when a failure is detected by automatic monitoring, it is determined whether the protection relay has a failure or the power system has a failure. An object of the present invention is to provide a highly reliable protection relay system that prevents unnecessary device locking of a relay device and does not lose a protection function.

[0009]

In order to achieve the above object, in the protection relay system according to the present invention, in the invention according to the first aspect, the amount of electricity is taken from the electric power system, and arithmetic processing is performed to protect the electric power system. In a protection relay system having a plurality of protection relay devices provided with an automatic monitoring function, a communication network connected to the plurality of protection relay devices and receiving automatic monitoring data of the plurality of protection relay devices via the communication network. A central determination device that determines whether or not all the failure detection times of the plurality of protection relay devices are within a predetermined time range based on the automatic monitoring data. If it is within the predetermined time range, it is determined that there is a failure on the power system side, and the central determination device sends a device lock command to any protection relay device. Characterized by being so free.

According to the protection relay system having the above-mentioned configuration, even when a plurality of protection relay devices detect a failure by automatic monitoring, if the failure detection time is detected almost simultaneously within a predetermined time range, a failure on the power system side will occur. Judgment is made and unnecessary device lock is not performed.

According to a second aspect of the present invention, there is provided a protection relay system including a plurality of protection relay devices having a plurality of protection relay devices having an automatic monitoring function while taking in an amount of electricity from a power system and performing arithmetic processing to protect the power system. A communication network connected to the plurality of protection relay devices, and a central determination device for receiving automatic monitoring data of the plurality of protection relay devices via the communication network, wherein the plurality of protection relays are based on the automatic monitoring data. It is determined whether the failure detection times of the devices are all within a predetermined time, and if the failure detection time is within the predetermined time, it is determined that the power system side is defective, and any of the protection relay devices is determined by the central determination device. , The device lock command is not transmitted.

According to the protection relay system having the above-described configuration, even when a plurality of protection relay devices detect a defect by automatic monitoring, if the failure detection time of each protection relay device is within a predetermined time, the power system side. Judgment as failure and do not perform unnecessary device lock.

According to the third aspect of the present invention, there is provided the first aspect of the invention.
In the protection relay system described above, based on the arrival time of the automatic monitoring data collected by the central determination device via a communication network, whether the failure detection times of the plurality of protection relay devices are all within a predetermined time range. Is determined.

According to the protection relay system having the above configuration, even when a plurality of protection relay devices detect a failure by automatic monitoring, the failure detection time based on the arrival time of the automatic monitoring data determines failures almost simultaneously within a predetermined time range. If it is detected, it is determined that a failure has occurred on the power system side, and unnecessary device lock is not performed.

According to a fourth aspect of the present invention, there is provided a protection relay system having a plurality of protection relay devices having a plurality of protection relay devices having an automatic monitoring function while taking in an electric quantity from a power system and performing arithmetic processing to protect the power system. A communication network connected to the plurality of protection relay devices, and a central determination device for receiving automatic monitoring data of the plurality of protection relay devices via the communication network; and a plurality of protection relay devices based on the automatic monitoring data. In any case, it is detected whether the failure detection contents are the same or not, and if the contents detected by the plurality of protection relay devices are identical, it is determined that the failure is on the power system side, and the central determination device The device lock command is not sent to the protection relay device.

According to the protection relay system having the above-described configuration, even when a plurality of protection relay devices detect a failure by automatic monitoring, if the detected failures of the individual protection relay devices are the same, a failure on the power system side may occur. Judgment is made and unnecessary device lock is not performed.

According to the invention described in claim 5, according to claim 4,
In the protection relay system described in (1), the determination as to whether or not the failure detection contents are the same is performed by taking into account whether or not electric energy is taken in from the same device as a determination condition.

According to the protection relay system having the above-described configuration, even when a plurality of protection relay devices detect a failure by automatic monitoring, if the failure detection of each of the protection relay devices is the same, a failure on the power system side may occur. Judgment is made and unnecessary device lock is not performed.

According to the invention described in claim 6, according to claim 4 of the present invention,
The protection relay system according to the above, characterized in that the determination of whether or not the failure detection content is the same is taken into consideration as a determination condition as to whether or not the amount of electricity is taken from the same point in the power system. And

According to the protection relay system having the above configuration,
Even when a plurality of protection relay devices detect a failure by automatic monitoring, if the failure detection of each protection relay device is the same, it is determined that a failure has occurred on the power system side, and unnecessary device locking is not performed.

Further, according to the invention of claim 7, according to claim 1,
In the protection relay system according to any one of (6) to (6), a protection relay device having a large influence on a system due to a malfunction is locked from a failure content detected by a plurality of protection relay devices,
A protection relay device that has little effect on the system due to a malfunction does not lock the device. According to the protection relay system having the above-described configuration, only devices that have a large influence on the system due to a malfunction are device-locked.

According to the invention described in claim 8, according to claim 7,
In the protection relay system described in, the conditions that lock the device that has a large effect on the system due to malfunction from the failure content detected by multiple protection relay devices, and do not lock the device that has little effect on the system due to the malfunction. It can be changed according to related equipment conditions.

According to the protection relay system having the above-described structure, only devices that have a large influence on the system due to malfunctions are locked, so that the required minimum device lock is achieved.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a first embodiment of the protection relay system of the present invention. The protection relay system according to the present invention including a plurality of protection relay devices 21A, 21B, and 21C and a central determination device 14 that takes in the electric quantity and the device information such as a circuit breaker and a disconnector from the power system, includes a plurality of protection relay devices. Communication network 13 for exchanging data
Connected by The present invention uses data of a plurality of protection relay devices that have detected a defect, sends data to the central determination device 14 via the communication network 13, determines whether or not to send a device lock command, and determines whether an internal device of the protection relay device is required. This is a protection relay system that suppresses device lock information for devices that do not need to be locked, and minimizes the lock range.

FIG. 2 shows a specific example of the first embodiment of the present invention. The failure detection processing of the protection relay device is performed by known automatic monitoring, and utilizes a communication network 13 capable of exchanging data between a plurality of protection relay devices.

In FIG. 2, a plurality of protection relay devices 10
When a failure of the protection relay device is detected by the automatic monitoring (software) processing unit 11 of A, 10B,... 10N, the detection time at that time is stored, and the failure content and detection time are communicated by the failure detection data transmission processing unit 12. The information is transmitted to the central determination device 14 via the network 13. In the central judging device 14, each protection relay device 10A, 1
0B,... When the failure detection time of each protection relay device is within the predetermined time range based on the information of 10N, that is, when the failure is detected between minutes and seconds. In this case, it is determined that a failure has occurred on the power system side, and the central determination device 14 suppresses the device lock command from being sent to any of the protection relay devices. In short, when a plurality of protection relay devices detect a defect at substantially the same time, it can be said that the cause is not a cause specific to the protection relay device but a common cause specific to the power system side. As a result, even when an automatic monitoring failure is detected due to a failure phenomenon on the power system side, the original protection function is continued without unnecessarily locking the device. On the other hand, if the failure detection time is not detected within the predetermined time range, it is determined that the protection relay device is defective, and the failure protection relay device is identified from the failure detection date and time data. A device lock command is sent out via the. In the protection relay device, the device lock receiving unit 16 receives the device lock command via the communication network 13,
The last stage of the protection relay function is locked.

According to the first embodiment of the present invention, even when a plurality of protection relay devices detect a defect by automatic monitoring, if the defect detection time detects the defect almost simultaneously within a predetermined time range, That is, if there is a simultaneity, it is determined that a failure has occurred on the power system side, and unnecessary device lock is not performed. Therefore, the reliability of operation as a protection relay system is secured without losing the protection function of the power system.

Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the device lock determination process 15 in the central determination device 14 is performed based on the failure detection time data of the protection relay device that has detected a failure, and any of the protection relay devices has a failure detection time within a predetermined time. This is a method of detecting whether or not there is a device and performing device lock determination. Others are the same as the first embodiment shown in FIG. In short, since an accident that occurs in the power system does not last for a long time, if multiple protection relay devices detect a failure, the failure detection time of each protection relay device is the maximum value of the duration of an accident that can occur in the power system If the time is shorter than the predetermined time, it can be said that the cause is not a cause specific to the protection relay device but a common cause specific to the power system. As a result, it is determined that a failure has occurred on the power system side, and the central determination device 14 suppresses the device lock command from being sent to any of the protection relay devices.

On the other hand, when the failure detection time is not detected within the predetermined time, that is, when the failure detection continues for the predetermined time or more, it is determined that the protection relay device is defective individually, and the failure protection relay device is determined from the failure detection date and time data. And sends a device lock command to the protection relay device via the communication network 13. In the protection relay device, the device lock receiving unit 16 receives the device lock command via the communication network 13, and locks the last stage of the protection relay function.

According to the second embodiment of the present invention, even when a plurality of protection relay devices detect a failure by automatic monitoring, if the failure detection time of each protection relay device is within a predetermined time, Unnecessary device locking is not performed by judging that a failure has occurred on the power system side. Therefore, the reliability of operation as a protection relay system is secured without losing the protection function of the power system. Further, since the failure detection time of each protection relay device is monitored, even if the detection timing is slightly shifted, a large error does not occur.

Next, a third embodiment of the present invention will be described with reference to FIG. In the central determination device 14, each protection relay device 10
If the failure detection time of each protection relay device is within a predetermined time range based on the arrival time of the information of A, 10B,. At 14, the device lock command is suppressed so as not to be sent to any of the protection relay devices.

According to the third embodiment of the present invention, even when a plurality of protection relay devices detect a defect by automatic monitoring, the protection relay devices 10A, 10B,... If a failure is detected almost simultaneously within a predetermined time range, the failure is judged to be a failure on the power system side, and unnecessary device lock is not performed, and therefore, the protection relay system without losing the protection function of the power system. The operation reliability is secured. Further, since the failure detection time is monitored on the central determination device 14 side based on the arrival time, the configuration of the protection relay device side can be simplified.

Next, a fourth embodiment of the present invention will be described with reference to FIG. This is a method in which the determination processing 15 of the central determination device 14 is performed based on the coincidence of the occurrence of a defect, but the determination is performed by focusing on the content of the defect. That is, any of the plurality of protection relay devices at the same electric station detects from the automatic monitoring data whether the failure detection content is the same. If the contents detected by multiple protection relay devices based on this detection result are the same, it is determined that a failure has occurred on the power system side, and unnecessary device lock is not performed, and thus the protection function of the power system is lost. The reliability of operation as a protection relay system is ensured without being affected.

If the contents of the detected faults are not identical, it is determined that the protection relay device is faulty, the fault protection relay device is specified from the fault detection data, and the protection relay device is connected to the protection relay device via the communication network 14. Send lock command. In the protection relay device, the device lock receiving unit 16 receives the device lock command via the communication network 13,
The last stage of the protection relay function is locked.

According to the fourth embodiment of the present invention, even when a plurality of protection relay devices detect a failure by automatic monitoring, the failure detection contents of the information of the protection relay devices 10A, 10B,... If the detected failures are the same, the power system side is determined to be faulty and unnecessary device locking is not performed.Therefore, the reliability of operation as a protection relay system without losing the protection function of the power system. Is secured. Further, since the failure detection contents are monitored, the failure can be more clearly determined as a system.

Next, a fifth embodiment of the present invention will be described with reference to FIG. In the device lock determination process 15 of the central determination device 14, the detection determination as to whether or not the failure detection content of any of the protection relay devices is the same is taken into consideration as to whether or not electric energy is taken from the same device as a determination condition. Adjacent current transformers C, such as the protective relay devices 21B and 21C of FIG.
A bus separation protection relay device connected to T, a bus protection relay device, and the like. Others are the same as FIG.

According to the fifth embodiment of the present invention, even when a plurality of protection relay devices detect a defect by automatic monitoring, based on the failure detection contents of the information of each protection relay device 10A, 10B,... 10N. Judgment is made, and if the failure detection contents are the same, it is judged that there is a failure on the power system side, and unnecessary device lock is not performed. Secured.

Next, a sixth embodiment of the present invention will be described with reference to FIG. In the device lock determination process 15 of the central determination device 14, it is determined whether or not the amount of electricity is taken in from the same point in the power system in the determination of whether or not the failure detection content of any of the protection relay devices is the same. It is added as a condition. Others are the same as FIG.

According to the sixth embodiment of the present invention, even when a plurality of protection relay devices detect a defect by automatic monitoring, based on the failure detection contents of the information of each protection relay device 10A, 10B,... 10N. Judgment is made, and if the failure detection contents are the same, it is judged that there is a failure on the power system side and unnecessary device lock is not performed, so that the reliability of operation as a protection relay system without losing the protection function of the power system. Secured.

Next, a seventh embodiment of the present invention will be described with reference to FIG. In the device lock determination process 15 of the central determination device 14, the device lock determination is performed in consideration of the magnitude of the influence of the malfunction on the system. For example, in the case of a failure of a substrate that is not directly involved in protection, the device is not locked because the influence on the system is small. According to this embodiment, reliability can be further improved without performing unnecessary device locking.

Next, an eighth embodiment of the present invention will be described with reference to FIG. In the present embodiment, the device lock determination process of the central determination device 14 is different from the seventh embodiment of FIG.
This is a method that can be changed according to the status of related equipment.
For example, there is a method in which a condition of a circuit breaker or a disconnecting device connected to a power system is fetched, and a device lock command due to the analog input monitoring failure at the time of “open” is locked. Others are the same as FIG. 2 to FIG. According to the above embodiment, when a plurality of protection relay devices detect a defect at the same time, or when the detected defects have the same content, the device can be prevented from being locked unnecessarily. Even when the lock condition is satisfied, the device lock can be prevented by the equipment condition on the system and can be kept to the minimum necessary.

Next, a ninth embodiment of the present invention will be described with reference to FIG. In the present embodiment, in the first to eighth embodiments, a plurality of protection relay devices are expanded to devices in an electric station opposite to devices in the own place, and a device lock determination is performed. It is a method. The transmission line protection relay device that exchanges data with the partner electrical station is the target. Others are the same as those of the first to eighth embodiments.

According to the above-described embodiment, if a failure is detected simultaneously by the protection relay devices that extend over a plurality of electrical stations, or if the detected failures have the same content, the device should not be locked unnecessarily. It is possible to do.

Next, a tenth embodiment of the present invention will be described with reference to FIG. In the present embodiment, the inspection start determination unit 17 performs an automatic inspection of the protection relay device that is not locked according to the result determined by the central determination device 14. Others are the same as those of the first to eighth embodiments.

According to the above-described embodiment, when a plurality of protection relay devices detect a defect at the same time, or when the detected defects have the same content, it is possible to prevent unnecessary device locking. In addition, since the protection relay device is automatically inspected, the reliability is further improved.

Further, in the first to tenth embodiments, the system lock judging process may be incorporated in a protection relay device connected to the same communication network.
In this manner, when a plurality of protection relay devices detect a defect at the same time, or when the detected defects have the same content, it is possible to prevent unnecessary device locking.

[0047]

As described above, according to the present invention, failure detection data of a plurality of protection relay devices is transmitted to a central determination device via a communication network, and the central determination device detects failure of each protection relay device. Based on the data failure detection time, failure detection time, or failure detection content, it is determined whether the failure is on the power system side or the protection relay device is defective. Since the device lock is not applied, it is an object to prevent unnecessary device lock of the protection relay device and provide a highly reliable protection relay system.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a protection relay system viewed from a system configuration showing an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of a protection relay system according to a first embodiment of the present invention.

FIG. 3 is a block diagram showing the configuration of a protection relay system according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing the configuration of a protection relay system according to a third embodiment of the present invention.

FIG. 5 is a block diagram showing the configuration of a protection relay system according to a fourth embodiment of the present invention.

FIG. 6 is a block diagram showing the configuration of a protection relay system according to a fifth embodiment of the present invention.

FIG. 7 is a block diagram showing the configuration of a protection relay system according to a sixth embodiment of the present invention.

FIG. 8 is a configuration block diagram of a protection relay system according to a seventh embodiment of the present invention.

FIG. 9 is a block diagram showing the configuration of a protection relay system according to an eighth embodiment of the present invention.

FIG. 10 is a configuration block diagram of a protection relay system according to a ninth embodiment of the present invention.

FIG. 11 is a block diagram showing the configuration of a protection relay system according to a tenth embodiment of the present invention.

FIG. 12 is a functional block diagram of a general protection relay device.

FIG. 13 is a block diagram for explaining a device lock function in the protection relay device.

[Explanation of symbols]

10A, 10B, 10N ... protection relay device, 11 ... automatic monitoring processing unit, 1
2 Failure detection data transmission processing, 13 ... communication network, 14
... Central determination device, 15 Device lock determination processing unit, 16 ... Device lock reception unit, 21A ... Transmission line protection relay device, 21B ... Bus separation relay device, 21C ... Bus protection relay device, 22 ... Circuit breaker (CB), 23 ... current transformer (CT), 25 ... input converter, 26
... A / D conversion unit, 27 ... Memory unit, 28 ... Calculation unit (MP
U), 29 ROM, 30 input interface (D /
I), 31: output interface (D / O), 32: transformer (PT).

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hoshi Mamoru 2-24-24 Harumi-cho, Fuchu-shi, Tokyo Toshiba System Technology Corporation F-term (reference) 5G042 GG01 GG07 5G064 AA04 AB03 AC03 AC05 CA07 CB16 DA01

Claims (8)

[Claims] 1. A protection relay system having a plurality of protection relay devices having a plurality of protection relay devices provided with an automatic monitoring function while taking in an amount of electricity from a power system and performing arithmetic processing to protect the power system. Communication network, and a central determination device that receives automatic monitoring data of a plurality of protection relay devices via the communication network, and any of the failure detection times of the plurality of protection relay devices based on the automatic monitoring data. It is determined whether or not the time is within a predetermined time range. If any of the failure detection times is within the predetermined time range, it is determined that a failure has occurred on the power system side, and the central determination device determines which protection relay device is used. A protection relay system characterized in that the device lock command is not sent even if the device is locked. 2. A protection relay system having a plurality of protection relay devices having a plurality of protection relay devices having an automatic monitoring function while taking in an amount of electricity from a power system and performing arithmetic processing to protect the power system. And a central determination device that receives automatic monitoring data of a plurality of protection relay devices via the communication network, and any of the failure detection times of the plurality of protection relay devices based on the automatic monitoring data. It is determined whether or not it is within a predetermined time, and if the failure detection time is within the predetermined time, it is determined that a failure has occurred on the power system side, and the central determination device issues a device lock command to any protection relay device. A protection relay system characterized in that transmission is not performed. 3. The protection relay system according to claim 1, wherein a failure detection time of each of the plurality of protection relay devices is predetermined based on an arrival time of the automatic monitoring data collected by a central determination device via a communication network. A protection relay system characterized in that it is determined whether or not it is within a time range. 4. A protection relay system having a plurality of protection relay devices having a plurality of protection relay devices having an automatic monitoring function while taking in electricity quantity from a power system and performing arithmetic processing to protect the power system. A central determination device that receives automatic monitoring data of a plurality of protection relay devices via the communication network, and any of the plurality of protection relay devices based on the automatic monitoring data has a failure detection content. Detects whether they are the same or not, and if the contents of failure detection by multiple protection relay devices are the same, determines that there is a failure on the power system side, and the central determination device applies the device to any protection relay device A protection relay system characterized by not sending a lock command. 5. The protection relay system according to claim 4, wherein the determination as to whether or not the failure detection contents are the same includes a determination as to whether or not electric energy is taken from the same device. A protection relay system characterized by the following. 6. The protection relay system according to claim 4, wherein the determination as to whether or not the failure detection contents are the same includes a determination as to whether or not electricity is taken from the same point in the power system. A protection relay system characterized by: 7. The protection relay system according to claim 1, wherein a device having a large effect on a system due to a malfunction is locked based on a failure content detected by a plurality of protection relay devices, and a device having a small effect on the system due to a malfunction. Is a protection relay system characterized by not locking. 8. A protection relay system according to claim 7, wherein a device having a large influence on a system due to a malfunction is locked based on a failure content detected by a plurality of protection relay devices, and a device having a small effect on the system due to a malfunction is locked. A protection relay system characterized in that conditions that are not allowed to be changed can be changed according to conditions of related equipment.