Protective relay system and power system protection method

Abstract

To achieve a protection relay system with high operational reliability without increasing costs.SOLUTION: Each of first and second IEDs includes a calculation unit for a first protection relay M, a calculation unit for a first protection relay FD, a calculation unit for a second protection relay M, and a calculation unit for a second protection relay FD. The calculation unit for the first protection relay FD and the calculation unit for the second protection relay M of the first IED as well as the calculation unit for the second protection relay FD and the calculation unit for the first protection relay M of the second IED has a lock function that locks an output of an accident determination result. A first MU, when receiving information indicating that an accident has occurred on a first object to be protected from the calculation unit for the first protection relay M and the calculation unit for the first protection relay FD, switches off a first circuit breaker, and a second MU, when it receives information indicating that an accident has occurred on a second object to be protected from the calculation unit for the second protection relay M and the calculation unit for the second protection relay FD, switches off a second circuit breaker.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a protective relay system and a power system protection method. [Background technology]

[0002] In recent years, studies have been underway to digitalize substation networks in order to reduce costs by streamlining substation equipment. For example, in the case of protection and control systems, the realization of digital transmission by replacing the control cable between the substation's main unit and the protection and control device with an optical cable instead of the conventional metal wire is being considered.

[0003] Traditionally, protective relay systems in Japan have output tripping commands in a fail-safe configuration, with the main (hereafter referred to as M) element and the fail-safe (hereafter referred to as FD) element mounted on separate CPU boards to prevent malfunctions caused by a single CPU board failure. Also, by configuring M and FD with different relay elements, it is possible to prevent malfunctions caused by a failure on the main side.

[0004] Protective relay systems in Japan are classified into extra-high voltage systems and low voltage systems according to voltage class. Extra-high voltage protective relay systems have a dual system configuration, as the impact of a system accident caused by a malfunction or failure is wide, and so they are designed to be redundant so that if one system fails, the protective function can continue to function normally as long as the other system is normal.

[0005] On the other hand, the protection relay system for low-level systems is configured as a single system because the impact of a system accident due to malfunction or failure is limited, and since a failure in the single system will result in the loss of protection function, it is vulnerable in terms of preventing malfunction or failure.

[0006] Background art of the present invention includes Japanese Patent Application Laid-Open No. 2010-068594 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2018-129885 (Patent Document 2).

[0007] Patent Document 1 states that "a system is provided with: a plurality of protection and control units connected to a first bus that transmits analog inputs and device information from substation equipment as serial data and a second bus that transmits protection and control information of the substation equipment as serial data, and that perform protection and control calculations for the substation equipment; a database unit connected to the second bus that stores unit information including the software and setting values ​​of each protection and control unit; and a standby protection and control unit connected to the first bus and the second bus that, in the event of a failure of one of the plurality of protection and control units, is able to operate as a substitute for the protection and control unit by downloading the unit information of the protection and control unit from the database unit via the second bus" (see abstract).

[0008] Patent Document 2 states that "the protective relay of the embodiment has a first AD conversion unit, a first processing unit, a second AD conversion unit, a second processing unit, and a selection unit. The first AD conversion unit converts analog information relating to power measured by a measurement unit provided in the power transmission facility into first digital information. The first processing unit generates first control information for a circuit breaker provided in the power transmission facility based on the first digital information. The second AD conversion unit converts analog information relating to power measured by the measurement unit into second digital information. The second processing unit generates second control information for the circuit breaker based on the second digital information. The selection unit selects the first control information and the second control information together to select the circuit breaker." If the information is to cause the circuit breaker to trip, control information instructing the circuit breaker to trip the circuit breaker is output (see summary). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-068594 [Patent Document 2] Japanese Patent Application Publication No. 2018-129885 Summary of the Invention [Problem to be solved by the invention]

[0010] In a digital substation, an IED (Intelligent Electronic Device) with a calculation unit and an MU (Merging Unit) with an input / output unit are connected via a transmission line, so each IED and MU is equipped with a CPU board. If the M and FD have separate CPU boards, the number of parts increases, which increases the failure rate and raises concerns about an increase in malfunctions.

[0011] In the technology described in Patent Document 1, a database device is installed separately from the protection and control device, and when the protection and control device fails, the database device downloads information about the failed device and operates as a replacement device for the failed protection and control device. However, since a separate database device must be installed, this is disadvantageous in terms of cost.

[0012] The technology described in Patent Document 2 is configured so that the M calculation unit and FD calculation unit evaluate the validity of the calculation results via a communication unit and monitor for discrepancies between the output results and the contact operation of the circuit breaker, but in terms of malfunction and non-operation in the event of a single failure in the calculation unit (CPU) in a single-system configuration, it has the same reliability as conventional protective relay systems.

[0013] Therefore, one aspect of the present invention provides a protective relay system with high operational reliability without increasing costs. [Means for solving the problem]

[0014] In order to solve the above-mentioned problems, one aspect of the present invention employs the following configuration: A protective relay system includes a first IED and a second IED, each including a first protective relay main calculation unit, a first protective relay fail-safe calculation unit, a second protective relay main calculation unit, and a second protective relay fail-safe calculation unit, which perform fault determination, a first MU that outputs a tripping command to a first circuit breaker provided in a first protected object, and a second MU that outputs a tripping command to a second circuit breaker provided in a second protected object, and the first protective relay fail-safe calculation unit and the second protective relay main calculation unit of the first IED and the second protective relay fail-safe calculation unit of the second IED are The second protection relay fail-safe calculation unit and the first protection relay main calculation unit have a lock function for locking the output of the result of the accident determination, the first MU acquires main information and fail-safe information for the accident determination for the first protected object and transmits them to the first IED and the second IED, the second MU acquires main information and fail-safe information for the accident determination for the second protected object and transmits them to the first IED and the second IED, and the first protection relay fail-safe calculation unit and the first protection relay main calculation unit have a lock function for locking the output of the result of the accident determination, the first MU acquires main information and fail-safe information for the accident determination for the second protected object and transmits them to the first IED and the second IED, the protection relay main calculation unit determines whether an accident has occurred in the first protected object based on main information of the first protected object in the accident determination, the first protection relay failsafe calculation unit of the first IED and the second IED determines whether an accident has occurred in the first protected object based on failsafe information of the first protected object in the accident determination, the second protection relay main calculation unit of the first IED and the second IED determines whether an accident has occurred in the second protected object based on main information of the second protected object in the accident determination, and the first protection relay failsafe calculation unit of the first IED and the second IED determines whether an accident has occurred in the second protected object based on failsafe information of the second protected object in the accident determination, and when the first MU receives information indicating that an accident has occurred in the first protected object as a result of the accident determination from the first protection relay main calculation unit of the first IED or the second IED and the first protection relay failsafe calculation unit of the first IED or the second IED,The second MU outputs a tripping command to the first circuit breaker, and when the second MU receives information indicating that an accident has occurred in the second protected object as a result of the accident determination from the second protective relay main calculation unit of the first IED or the second IED and the second protective relay fail-safe calculation unit of the first IED or the second IED, the second MU outputs a tripping command to the second circuit breaker. [Effects of the Invention]

[0015] According to one aspect of the present invention, a protective relay system with high operational reliability is realized without increasing costs.

[0016] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a block diagram showing a configuration example of a protection relay system in a digital substation in which a function-aggregated IED device according to a first embodiment is installed. [Figure 2] 10 is a flowchart showing an example of processing executed by the first protection relay M calculation unit and the first protection relay FD calculation unit of the first protection relay IED in Example 1 for each calculation cycle of the CPU board of the first protection relay IED. [Figure 3] 10 is a flowchart showing an example of processing executed by the first protection relay M calculation unit and the first protection relay FD calculation unit of the second protection relay IED in Example 1 for each calculation cycle of the CPU board of the second protection relay IED. [Figure 4] 10 is a flowchart showing an example of processing executed by the second protection relay M calculation unit and the second protection relay FD calculation unit of the first protection relay IED in Example 1 for each calculation cycle of the CPU board of the first protection relay IED. [Figure 5] 10 is a flowchart showing an example of processing executed by the second protection relay M calculation unit and the second protection relay FD calculation unit of the second protection relay IED in Example 1 for each calculation cycle of the CPU board of the second protection relay IED. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In this embodiment, the same components are generally designated by the same reference numerals, and repeated explanations will be omitted. It should be noted that this embodiment is merely an example for realizing the present invention, and does not limit the technical scope of the present invention. [Example]

[0019] Figure 1 is a block diagram showing an example of the configuration of a protective relay system in a digital substation equipped with a function-aggregated IED device. A low-level protective relay system is assumed as an example of the configuration of the protective relay system in this digital substation. In the digital substation of this embodiment, data transmission is performed based on the IEC (International Electrotechnical Commission) 61850 standard, for example.

[0020] The protective relay system that protects the power system includes one system of a first protective relay IED (Intelligent Electronic Device) 1 and a first protective relay MU (Merging Unit) 3, and one system of a second protective relay IED 2 and a second protective relay MU 4. The first protective relay IED 1, the second protective relay IED 2, the first protective relay MU 3, and the second protective relay MU 4 are connected via a transmission line 33.

[0021] The MU3 for the first protective relay is connected to a first circuit breaker (not shown) provided in the first protected object (power system or power equipment). The MU4 for the second protective relay is connected to a second circuit breaker (not shown) provided in the second protected object (power system or power equipment).

[0022] Each of the first protective relay IED1 and the second protective relay IED2 is equipped with one CPU (Central Processing Unit) board.

[0023] The first protective relay IED1 includes a first protective relay M (main) calculation unit 11, a first protective relay FD (fail-safe) calculation unit 12, a second protective relay M calculation unit 13, and a second protective relay FD calculation unit 14. The second protective relay IED2 includes a second protective relay M calculation unit 21, a second protective relay FD calculation unit 22, a first protective relay M calculation unit 23, and a first protective relay FD calculation unit 24.

[0024] For example, one CPU board implemented in each of the IED1 for the first protection relay and the IED2 for the second protection relay has multiple cores (for example, four cores), and the above-mentioned calculation units are implemented by software on different cores (one calculation unit is implemented on one core).

[0025] In the first protective relay IED 1, the first protective relay M calculation unit 11 and the second protective relay FD calculation unit 14 do not have an interlock function, while the first protective relay FD calculation unit 12 and the second protective relay M calculation unit 13 do. In the second protective relay IED 2, the second protective relay M calculation unit 21 and the first protective relay FD calculation unit 24 do not have an interlock function, while the second protective relay FD calculation unit 22 and the first protective relay M calculation unit 23 do. In order to realize the above-mentioned interlock function, for example, the first protective relay IED 1 and the second protective relay IED 2 each include an interlock circuit.

[0026] In Figure 1, of the calculation units included in the IED1 for the first protective relay and the IED2 for the second protective relay, the calculation units that do not have an interlock function are shown with solid lines, and the calculation units that have an interlock function are shown with dotted lines.

[0027] In addition, each of the first protective relay IED 1 and the second protective relay IED 2 includes a communication control unit 32 , and the communication control unit 32 includes an information transmitting / receiving unit 31 .

[0028] It should be noted that the first protective relay IED1 and the second protective relay IED2 each have a function to detect abnormalities in their own CPU boards (for example, a watchdog timer, a sum check, or an invalidity check).

[0029] The first protective relay MU3 includes a first protective relay input / output unit 41, a first protective relay M circuit breaker contact (MX1) 42, and a first protective relay FD circuit breaker contact (FDX1) 43. The second protective relay MU4 includes a second protective relay input / output unit 51, a second protective relay M circuit breaker contact (MX2) 52, and a second protective relay FD circuit breaker contact (FDX2) 53. The first protective relay MU3 and the second protective relay MU4 both include a communication control unit 34, and the communication control unit 34 includes an information transceiver unit 35.

[0030] The first protection relay MU3 and the second protection relay MU4 each have a CPU board mounted thereon, and the first protection relay input / output unit 41 and the second protection relay input / output unit 51 are both mounted on the CPU board.

[0031] The first protective relay input / output unit 41 receives signals for the electrical quantities of the first protected object and signals from the main unit (first circuit breaker) as signals for M and FD for fault determination for the first protected object, converts the received signals into digital form, and outputs the digitally converted information (information for M and FD for fault determination) to the information transceiver unit 35 of the first protective relay MU 3. The communication control unit 34 of the first protective relay MU 3 transmits the information to the first protective relay IED 1 and the second protective relay IED 2 via the transmission path 33.

[0032] The second protective relay input / output unit 51 receives signals for the electrical quantities of the second protected object and signals from the main unit (second circuit breaker) as signals for M and FD for fault determination for the second protected object, converts the received signals into digital form, and outputs the digitally converted information (information for M and FD for fault determination) to the information transceiver unit 35 of the second protective relay MU4. The communication control unit 34 of the second protective relay MU4 transmits the information to the first protective relay IED1 and the second protective relay IED2 via the transmission path 33.

[0033] The communication control units 32 of the IED1 for the first protection relay and the IED2 for the second protection relay each receive information transmitted from the MU3 for the first protection relay and the MU4 for the second protection relay via the transmission path 33, and transmit the received information to the calculation unit via the information transmission / reception unit 31.

[0034] The first protective relay M calculation unit 11 and the first protective relay M calculation unit 23 each execute a fault determination as to whether a system fault (a system fault that requires the first protective relay to operate) has occurred in the first protected object, based on the information for M of the first protected object received from the communication control unit 32. When determining that a system fault has occurred in the first protected object, the first protective relay M calculation unit 11 and the first protective relay M calculation unit 23 each transmit a shutoff command to the information transmitting / receiving unit 31 of the IED to turn on the first protective relay M shutoff circuit contact 42.

[0035] The first protective relay FD calculation unit 12 and the first protective relay FD calculation unit 24 each execute an accident determination as to whether a system accident (a system accident that requires the first protective relay to operate) has occurred in the first protected object, based on the information for FD of the first protected object received from the communication control unit 32. When determining that a system accident has occurred in the first protected object, the first protective relay FD calculation unit 12 and the first protective relay FD calculation unit 24 each transmit a break command to the information transmitting / receiving unit 31 of the IED to turn on the breaker circuit contact 43 for the first protective relay FD.

[0036] The second protection relay M calculation unit 13 and the second protection relay M calculation unit 21 each perform an accident determination as to whether a system accident (a system accident that requires the second protection relay to operate) has occurred in the second protected object, based on the information for M of the second protected object received from the communication control unit 32. When determining that a system accident has occurred in the second protected object, the second protection relay M calculation unit 13 and the second protection relay M calculation unit 21 each transmit a break command to the information transmitting / receiving unit 31 of the IED to turn on the breaker circuit contact 52 for the second protection relay M.

[0037] The second protection relay FD calculation unit 14 and the second protection relay FD calculation unit 22 each execute an accident determination as to whether a system accident (a system accident that requires the second protection relay to operate) has occurred in the second protected object, based on the information for the FD of the second protected object received from the communication control unit 32. When the second protection relay FD calculation unit 14 and the second protection relay FD calculation unit 22 each determine that a system accident has occurred in the second protected object, they transmit a break command to the information transmitting / receiving unit 31 of the IED to turn on the breaker circuit contact 53 for the second protection relay FD.

[0038] However, when the CPU boards of the IED1 for the first protective relay and the IED2 for the second protective relay are normal, the output of a shut-off command to the information transmitter / receiver 31 of the IED1 for the first protective relay by the calculation unit 12 for the first protective relay FD and the calculation unit 13 for the second protective relay M is locked by the interlock function.

[0039] In addition, when the CPU boards of the IED1 for the first protective relay and the IED2 for the second protective relay are normal, the output of a shutoff command to the information transmitter / receiver 31 of the IED2 for the second protective relay by the calculation unit 22 for the second protective relay FD and the calculation unit 23 for the first protective relay M is locked by the interlock function.

[0040] When the communication control units 32 of the IED1 for the first protection relay and the IED2 for the second protection relay receive a shutdown command to turn on the shutdown circuit contact 42 for the first protection relay M or a shutdown command to turn on the shutdown circuit contact 43 for the first protection relay FD, they transmit the shutdown command to the MU3 for the first protection relay via the transmission path 33.

[0041] When the communication control units 32 of the IED1 for the first protection relay and the IED2 for the second protection relay receive a shutdown command to turn on the shutdown circuit contact 52 for the second protection relay M or a shutdown command to turn on the shutdown circuit contact 53 for the second protection relay FD, they transmit the shutdown command to the MU4 for the second protection relay via the transmission path 33.

[0042] When the communication control unit 34 of the MU3 for the first protection relay receives a tripping command from the IED1 for the first protection relay or the IED2 for the second protection relay, it transmits the received tripping command to the input / output unit 41 for the first protection relay via the information transmission / reception unit 35 of the MU3 for the first protection relay.

[0043] When the received tripping command is a tripping command to turn on the first protective relay M breaker circuit contact 42, the first protective relay input / output unit 41 turns on the first protective relay M breaker circuit contact 42. When the received tripping command is a tripping command to turn on the first protective relay FD breaker circuit contact 43, the first protective relay input / output unit 41 turns on the first protective relay FD breaker circuit contact 43. When both the first protective relay M breaker circuit contact 42 and the first protective relay FD breaker circuit contact 43 are turned on, an AND output of the M and FD of the first protective relay outputs a tripping command to the first circuit breaker, which is the main circuit breaker, causing the first circuit breaker to operate and thereby removing the system fault in the first protected object.

[0044] When the communication control unit 34 of the MU4 for the second protection relay receives a tripping command from the IED1 for the first protection relay or the IED2 for the second protection relay, it transmits the received tripping command to the input / output unit 51 for the second protection relay via the information transmission / reception unit 35 of the MU4 for the second protection relay.

[0045] If the received tripping command is a tripping command to turn on the second protective relay M breaker circuit contact 52, the second protective relay input / output unit 51 turns on the second protective relay M breaker circuit contact 52. If the received tripping command is a tripping command to turn on the second protective relay FD breaker circuit contact 53, the second protective relay input / output unit 51 turns on the second protective relay FD breaker circuit contact 53. When both the second protective relay M breaker circuit contact 52 and the second protective relay FD breaker circuit contact 53 are turned on, an AND output of the M and FD of the second protective relay outputs a tripping command to the second circuit breaker, which is the main circuit breaker, and the second circuit breaker operates, thereby eliminating the system fault in the second protected object.

[0046] Figure 2 is a flowchart showing an example of processing executed by the first protection relay M calculation unit 11 and the first protection relay FD calculation unit 12 of the first protection relay IED1 for each calculation cycle of the CPU board of the first protection relay IED1.

[0047] The first protective relay IED1 determines whether the CPU board of its own IED (the first protective relay IED1) is normal (S11). If the first protective relay IED1 determines that the CPU board of its own IED is abnormal (S11: NO), it uses the communication control unit 32 of its own IED to transmit the abnormality information to the other IED (the second protective relay IED2) ​​via the transmission path 33 (S15), and ends the processing (i.e., no fault determination is performed by the calculation units included in the first protective relay IED1). By the processing of step S15, the abnormality of the CPU board of the first protective relay IED1 is notified to the second protective relay IED2.

[0048] When the first protective relay IED1 determines that the CPU board of its own IED is normal (S11: YES), it determines whether the CPU board of another IED (the second protective relay IED2) ​​is normal (S12).

[0049] Specifically, for example, if the local IED receives abnormality information from another IED, it determines that the CPU board of the other IED is abnormal, and if it has not received abnormality information from the other IED, it determines that the CPU board of the other IED is normal. This also applies to step S22, which will be described later. Furthermore, if the first protective relay IED1 and the second protective relay IED determine that the board of the local IED is normal, they may transmit normality information to the other IED. In this case, if the local IED has not received abnormality information after receiving normality information from the other IED, it may determine that the CPU board of the other IED is normal.

[0050] If the IED1 for the first protective relay determines that the CPU boards of the other IEDs are normal (S12: YES), that is, if the CPU boards of both the IED1 for the first protective relay and the IED2 for the second protective relay are normal, including the determination result in step S11, the IED1 for the first protective relay locks the output of the shutdown command by the calculation unit having the interlock function of the IED1 for the first protective relay (calculation unit 12 for the first protective relay FD and calculation unit 13 for the second protective relay M) (S13).

[0051] Next, the calculation unit 11 for the first protection relay M and the calculation unit 12 for the first protection relay FD each make an accident determination to indicate whether a system accident has occurred based on the information received from the MU3 for the first protection relay. However, since the output of the tripping command by the calculation unit 12 for the first protection relay FD is locked in step S13, when the calculation unit 11 for the first protection relay M determines that a system accident has occurred in the first protected object, a tripping command is output to the information transmission / reception unit 31 of the communication control unit 32 of its own IED (IED1 for the first protection relay) (S16), and when the calculation unit 12 for the first protection relay FD determines that a system accident has occurred in the first protected object, a tripping command is not output.

[0052] If the IED1 for the first protective relay determines that the CPU board of the other IED is abnormal (S12: NO), that is, if the CPU board of the IED1 for the first protective relay is normal but the CPU board of the IED2 for the second protective relay is abnormal, including the determination result in step S11, the IED1 for the first protective relay releases the interlock of the calculation unit having the interlock function of the IED1 for the first protective relay (the calculation unit 12 for the first protective relay FD and the calculation unit 13 for the second protective relay M) (S14).

[0053] Next, the calculation unit 11 for the first protective relay M and the calculation unit 12 for the first protective relay FD each make an accident determination to indicate whether a system accident has occurred based on the information received from the MU3 for the first protective relay, and since the interlock of the calculation unit 12 for the first protective relay FD is released in step S14, when the calculation unit 11 for the first protective relay M determines that a system accident has occurred in the first protected object and when the calculation unit 12 for the first protective relay FD determines that a system accident has occurred in the first protected object, a shutdown command is output to the information transmission / reception unit 31 of the communication control unit 32 of the local IED (IED1 for the first protective relay) (S17).

[0054] Figure 3 is a flowchart showing an example of processing executed by the first protection relay M calculation unit 23 and the first protection relay FD calculation unit 24 of the second protection relay IED2 for each calculation cycle of the CPU board of the second protection relay IED2.

[0055] The second protective relay IED2 determines whether the CPU board of its own IED (the second protective relay IED2) ​​is normal (S21). If the second protective relay IED2 determines that the CPU board of its own IED is abnormal (S21: NO), it uses the communication control unit 32 of its own IED to transmit the abnormality information to the other IED (the first protective relay IED1) via the transmission path 33 (S25), and ends the processing (i.e., no fault determination is performed by the calculation units included in the second protective relay IED2). By the processing of step S25, the abnormality of the CPU board of the second protective relay IED2 is notified to the first protective relay IED1.

[0056] When the second protection relay IED2 determines that the CPU board of its own IED is normal (S21: YES), it determines whether the CPU board of the other IED (first protection relay IED1) is normal (S22).

[0057] If the IED2 for the second protective relay determines that the CPU boards of the other IEDs are normal (S22: YES), that is, if the CPU boards of both the IED1 for the first protective relay and the IED2 for the second protective relay are normal, including the determination result in step S21, the IED2 for the second protective relay locks the output of the shutdown command by the calculation unit having the interlock function of the IED2 for the second protective relay (calculation unit 22 for the second protective relay FD and calculation unit 23 for the first protective relay M) (S23).

[0058] Next, the calculation unit 23 for the first protection relay M and the calculation unit 24 for the first protection relay FD each make an accident determination to indicate whether a system accident has occurred based on the information received from the MU3 for the first protection relay. However, since the output of a shutdown command by the calculation unit 23 for the first protection relay M is locked in step S23, when the calculation unit 24 for the first protection relay FD determines that a system accident has occurred in the first protected object, a shutdown command is output to the information transceiver unit 31 of the communication control unit 32 of its own IED (IED2 for the second protection relay) (S26), and when the calculation unit 23 for the first protection relay M determines that a system accident has occurred in the first protected object, a shutdown command is not output.

[0059] If the IED2 for the second protective relay determines that the CPU board of the other IED is abnormal (S22: NO), that is, if the CPU board of the IED2 for the second protective relay is normal but the CPU board of the IED1 for the first protective relay is abnormal, including the determination result in step S21, the IED2 for the second protective relay releases the interlock of the calculation unit having the interlock function of the IED2 for the second protective relay (the calculation unit 22 for the second protective relay FD and the calculation unit 23 for the first protective relay M) (S24).

[0060] Next, the calculation unit 23 for the first protective relay M and the calculation unit 24 for the first protective relay FD each make an accident determination to indicate whether a system accident has occurred based on the information received from the MU3 for the first protective relay, and since the interlock of the calculation unit 23 for the first protective relay M is released in step S24, when the calculation unit 23 for the first protective relay M determines that a system accident has occurred in the first protected object and when the calculation unit 24 for the first protective relay FD determines that a system accident has occurred in the first protected object, a shutdown command is output to the information transmission / reception unit 31 of the communication control unit 32 of the local IED (IED2 for the second protective relay) (S27).

[0061] Fig. 4 is a flowchart showing an example of processing that the second protection relay M calculation unit 13 and the second protection relay FD calculation unit 14 of the first protection relay IED 1 execute for each calculation cycle of the CPU board of the first protection relay IED 1. The processing in Fig. 4 is the same as the processing in Fig. 2 except that instead of steps S16 and S17, the processing in steps S18 and S19, which will be described later, is executed.

[0062] Following the processing of step S13, the calculation unit 13 for the second protection relay M and the calculation unit 14 for the second protection relay FD each make an accident determination to indicate whether a system accident has occurred based on the information received from the MU4 for the second protection relay. However, since the output of a tripping command by the calculation unit 13 for the second protection relay M is locked in step S13, when the calculation unit 14 for the second protection relay FD determines that a system accident has occurred in the second protected object, a tripping command is output to the information transceiver unit 31 of the communication control unit 32 of its own IED (IED1 for the first protection relay) (S18), and when the calculation unit 13 for the second protection relay M determines that a system accident has occurred in the second protected object, a tripping command is not output.

[0063] Furthermore, following the processing of step S14, the second protection relay M calculation unit 13 and the second protection relay FD calculation unit 14 each make an accident determination indicating whether a system accident has occurred based on the information received from the second protection relay MU4, and since the interlock of the second protection relay M calculation unit 13 is released in step S14, when the second protection relay M calculation unit 13 determines that a system accident has occurred in the second protected object and when the second protection relay FD calculation unit 14 determines that a system accident has occurred in the second protected object, a shutdown command is output to the information transceiver unit 31 of the communication control unit 32 of the local IED (first protection relay IED1) (S19).

[0064] Fig. 5 is a flowchart showing an example of processing that the second protection relay M calculation unit 21 and the second protection relay FD calculation unit 22 of the second protection relay IED 2 execute for each calculation cycle of the CPU board of the second protection relay IED 2. The processing in Fig. 5 is the same as the processing in Fig. 3 except that instead of steps S26 and S27, the processing in steps S28 and S29, which will be described later, is executed, respectively.

[0065] Following the processing of step S23, the calculation unit 21 for the second protection relay M and the calculation unit 22 for the second protection relay FD each make an accident determination to indicate whether a system accident has occurred based on the information received from the MU4 for the second protection relay. However, since the output of a tripping command by the calculation unit 22 for the second protection relay FD is locked in step S23, when the calculation unit 21 for the second protection relay M determines that a system accident has occurred in the second protected object, a tripping command is output to the information transmission / reception unit 31 of the communication control unit 32 of its own IED (IED2 for the second protection relay) (S28), and when the calculation unit 22 for the second protection relay FD determines that a system accident has occurred in the second protected object, no tripping command is output.

[0066] Furthermore, following the processing of step S24, the calculation unit 21 for the second protective relay M and the calculation unit 22 for the second protective relay FD each make an accident determination indicating whether a system accident has occurred based on the information received from the MU4 for the second protective relay, and since the interlock of the calculation unit 22 for the second protective relay FD is released in step S24, when the calculation unit 21 for the second protective relay M determines that a system accident has occurred in the second protected object and when the calculation unit 22 for the second protective relay FD determines that a system accident has occurred in the second protected object, a shutdown command is output to the information transceiver unit 31 of the communication control unit 32 of the local IED (IED2 for the second protective relay) (S29).

[0067] The processing in FIGS. 2 to 5 can be summarized as follows.

[0068] If both the CPU board of the IED1 for the first protective relay and the CPU board of the IED2 for the second protective relay are normal, the M calculation for the first protective relay is performed in the calculation unit on the IED1 for the first protective relay, and the FD calculation for the first protective relay is performed in the calculation unit on the IED2 for the second protective relay by the processing of steps S16 and S26.

[0069] Furthermore, if both the CPU board of the IED1 for the first protective relay and the CPU board of the IED2 for the second protective relay are normal, the FD calculation for the second protective relay is performed in the calculation unit on the IED1 for the first protective relay, and the M calculation for the second protective relay is performed in the calculation unit on the IED2 for the second protective relay, by the processing of steps S18 and S28.

[0070] Therefore, when both the CPU board of the IED1 for the first protective relay and the CPU board of the IED2 for the second protective relay are normal, the M calculation and the FD calculation for both the first protective relay and the second protective relay are performed on different CPU boards, so that if one of the CPU boards fails, malfunction of the first protective relay and the second protective relay (operating when they should not operate) can be suppressed.

[0071] Furthermore, if the CPU board of only the first protective relay IED1 is abnormal, the processing of step S15 notifies the second protective relay IED2 of the abnormality in the CPU board of the first protective relay IED1, and the M calculation and FD calculation are not performed by each calculation unit included in the first protective relay IED1. Furthermore, the processing of step S24 releases the interlock of the second protective relay FD calculation unit 22 and the first protective relay M calculation unit 23 of the second protective relay IED2, and the processing of steps S27 and S29 cause the M calculation and FD calculation for the first protective relay and the M calculation and FD calculation for the second protective relay to be performed on the second protective relay IED2 whose CPU board is normal.

[0072] Similarly, if the CPU board of only the second protective relay IED2 is abnormal, the abnormality in the CPU board of the second protective relay IED2 is notified to the first protective relay IED1 by the processing of step S25, and the M calculation and FD calculation are not performed by each calculation unit included in the second protective relay IED2. Furthermore, the interlock of the first protective relay FD calculation unit 12 and the second protective relay M calculation unit 13 of the first protective relay IED1 is released by the processing of step S14, and the M calculation and FD calculation for the first protective relay and the M calculation and FD calculation for the second protective relay are performed on the first protective relay IED1 whose CPU board is normal by the processing of steps S17 and S19.

[0073] Therefore, if the CPU board of only one of the IED1 for the first protective relay or the IED2 for the second protective relay is abnormal, the M calculation and FD calculation for the first protective relay and the M calculation and FD calculation for the second protective relay are performed on the other normal CPU board, thereby preventing the first protective relay and the second protective relay from malfunctioning (not operating when they should operate).

[0074] Furthermore, the interlock function of the first protective relay IED1 and the second protective relay IED2 under normal conditions only locks the output of the tripping command, and each calculation unit whose output is locked by interlock is also constantly executing calculation processing, so there is no need to wait for the time it takes for information to be downloaded after a device fails, as is the case with the database device disclosed in Patent Document 1. In other words, even if an abnormality occurs in the CPU board of one of the first protective relay IED1 and the second protective relay IED2, the time from the occurrence of a system fault to the fault being cleared is short, improving the stability of the power system (each protected object).

[0075] As described above, the protective relay system of this embodiment can prevent malfunctions due to a single CPU board failure, even in a single-system protective relay system for low-level voltage systems used in Japan, because the M and FD are processed on separate CPU boards as in the past, and can also improve malfunction prevention in the event of a single CPU board failure compared to the past.

[0076] In addition, since there is no need to install additional IEDs for protective relays, it is also advantageous in terms of cost compared to the two-system configuration of the extra-high voltage system.

[0077] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0078] Furthermore, the above-described configurations, functions, processing units, processing means, etc. may be partially or entirely implemented in hardware, for example, by designing them as integrated circuits. The above-described configurations, functions, etc. may also be implemented in software, with a processor interpreting and executing a program that implements each function. Information such as the programs, tables, and files that implement each function can be stored in a memory, a recording device such as a hard disk or SSD (Solid State Drive), or a recording medium such as an IC card, SD card, or DVD.

[0079] In addition, the control lines and information lines shown are those that are considered necessary for the explanation, and do not necessarily show all the control lines and information lines in the product. In reality, it can be assumed that almost all components are interconnected. [Explanation of symbols]

[0080] 1 IED for first protective relay, 2 IED for second protective relay, 3 MU for first protective relay, 4 MU for second protective relay, 11 Calculation unit 11 for first protective relay M, 12 Calculation unit for first protective relay FD, 13 Calculation unit for second protective relay M, 14 Calculation unit for second protective relay FD, 21 Calculation unit for second protective relay M, 22 Calculation unit for second protective relay FD, 23 Calculation unit for first protective relay M, 24 Calculation unit for first protective relay FD, 41 Input / output unit for first protective relay, 42 Circuit breaker contact for first protective relay M, 43 Circuit breaker contact for first protective relay FD, 51 Input / output unit for second protective relay, 52 Circuit breaker contact for second protective relay M, 53 Circuit breaker contact for second protective relay FD

Claims

1. 1. A protective relay system comprising: a first IED and a second IED, each including a first protective relay main calculation unit, a first protective relay fail-safe calculation unit, a second protective relay main calculation unit, and a second protective relay fail-safe calculation unit, which perform accident determination; a first MU that outputs a breaker command to a first circuit breaker provided in a first protected object; a second MU that outputs a breaker command to a second circuit breaker provided in a second protected object, the first protection relay fail-safe calculation unit and the second protection relay main calculation unit of the first IED, and the second protection relay fail-safe calculation unit and the first protection relay main calculation unit of the second IED, have a lock function that locks an output of a result of the accident determination, The first MU acquires main information and fail-safe information for determining the accident with respect to the first protected object and transmits the information to the first IED and the second IED; The second MU acquires main information and fail-safe information for determining the accident with respect to the second protected object and transmits the information to the first IED and the second IED; The first protection relay main calculation unit of the first IED and the second IED determines whether an accident has occurred in the first protected object based on main information of the first protected object in the accident determination, The first protection relay fail-safe calculation unit of the first IED and the second IED determines whether an accident has occurred in the first protected object based on fail-safe information of the first protected object in the accident determination, The second protection relay main calculation unit of the first IED and the second IED determines whether an accident has occurred in the second protected object based on main information of the second protected object in the accident determination, The second protection relay fail-safe calculation unit of the first IED and the second IED determines whether an accident has occurred in the second protected object based on fail-safe information for the second protected object in the accident determination, the first MU outputs a tripping command to the first circuit breaker when receiving information indicating that an accident has occurred in the first protected object as a result of the accident determination from the first protective relay main calculation unit of the first IED or the second IED and the first protective relay fail-safe calculation unit of the first IED or the second IED; A protective relay system in which the second MU outputs a shutoff command to the second circuit breaker when it receives information from the second protective relay main calculation unit of the first IED or the second IED and the second protective relay failsafe calculation unit of the first IED or the second IED indicating that an accident has occurred in the second protected object as a result of the accident determination.

2. 2. The protective relay system according to claim 1, Each of the first IED and the second IED is a CPU board on which the first protection relay main calculation unit, the first protection relay fail-safe calculation unit, the second protection relay main calculation unit, and the second protection relay fail-safe calculation unit are mounted, Determine whether the CPU board included in itself is normal, When it is determined that the CPU board included in itself is abnormal, it outputs abnormality information to the other IED, If the CPU boards included in the first IED and the second IED are both normal, The first IED is The lock function locks the output of the accident determination result by the first protection relay fail-safe calculation unit and the second protection relay main calculation unit of the first IED, outputting a result of the fault determination by the first protection relay main calculation unit of the first IED to the first MU; outputting a result of the accident determination by the second protective relay fail-safe calculation unit of the first IED to the second MU; The second IED is The lock function locks the output of the accident determination result by the second protection relay fail-safe calculation unit and the first protection relay main calculation unit of the second IED, outputting a result of the fault determination by the second protection relay main calculation unit of the second IED to the second MU; A protective relay system that outputs the result of the accident determination by the first protective relay fail-safe calculation unit of the second IED to the first MU.

3. 3. The protective relay system according to claim 2, If the CPU board included in the first IED is abnormal, the first IED stops the accident determination by the first protection relay main calculation unit, the first protection relay fail-safe calculation unit, the second protection relay main calculation unit, and the second protection relay fail-safe calculation unit of the first IED, The second IED is unlocking the output of the accident determination by the lock function in the second protection relay fail-safe calculation unit and the first protection relay main calculation unit of the second IED; outputting a result of the fault determination by the second protection relay main calculation unit of the second IED to the second MU; outputting a result of the accident determination by the second protection relay fail-safe calculation unit of the second IED to the second MU; outputting a result of the fault determination by the first protection relay main calculation unit of the second IED to the first MU; A protective relay system that outputs the result of the accident determination by the first protective relay fail-safe calculation unit of the second IED to the first MU.

4. 3. The protective relay system according to claim 2, If the CPU board included in the second IED is abnormal, the second IED stops the accident determination by the first protection relay main calculation unit, the first protection relay fail-safe calculation unit, the second protection relay main calculation unit, and the second protection relay fail-safe calculation unit of the second IED, The first IED is unlocking the lock of the output of the accident determination by the lock function in the first protection relay fail-safe calculation unit and the second protection relay main calculation unit of the first IED; outputting a result of the fault determination by the first protection relay main calculation unit of the first IED to the first MU; outputting a result of the accident determination by the first protective relay fail-safe calculation unit of the first IED to the first MU; outputting a result of the fault determination by the second protection relay main calculation unit of the first IED to the second MU; A protective relay system that outputs the result of the accident determination by the second protective relay fail-safe calculation unit of the first IED to the second MU.

5. A method for protecting a power system using a protective relay system, comprising: The protective relay system includes: a first IED and a second IED, each including a first protective relay main calculation unit, a first protective relay fail-safe calculation unit, a second protective relay main calculation unit, and a second protective relay fail-safe calculation unit, which perform accident determination; a first MU that outputs a breaker command to a first circuit breaker provided in a first protected object; a second MU that outputs a breaker command to a second circuit breaker provided in a second protected object, the first protection relay fail-safe calculation unit and the second protection relay main calculation unit of the first IED, and the second protection relay fail-safe calculation unit and the first protection relay main calculation unit of the second IED, have a lock function that locks an output of a result of the accident determination, The power system protection method includes: The first MU acquires main information and fail-safe information for determining the accident with respect to the first protected object and transmits the information to the first IED and the second IED; The second MU acquires main information and fail-safe information for determining the accident with respect to the second protected object and transmits the information to the first IED and the second IED; The first protection relay main calculation unit of the first IED and the second IED determines whether an accident has occurred in the first protected object based on main information of the first protected object in the accident determination, The first protection relay fail-safe calculation unit of the first IED and the second IED determines whether an accident has occurred in the first protected object based on fail-safe information of the first protected object in the accident determination, The second protection relay main calculation unit of the first IED and the second IED determines whether an accident has occurred in the second protected object based on main information of the second protected object in the accident determination, The second protection relay fail-safe calculation unit of the first IED and the second IED determines whether an accident has occurred in the second protected object based on fail-safe information for the second protected object in the accident determination, When the first MU receives information indicating that an accident has occurred in the first protected object as a result of the accident determination from the first protective relay main calculation unit of the first IED or the second IED and the first protective relay fail-safe calculation unit of the first IED or the second IED, the first MU outputs a tripping command to the first circuit breaker; A power system protection method, in which the second MU outputs a shutdown command to the second circuit breaker when it receives information from the second protection relay main calculation unit of the first IED or the second IED and the second protection relay fail-safe calculation unit of the first IED or the second IED indicating that an accident has occurred in the second protected object as a result of the accident determination.

6. 6. The power system protection method according to claim 5, Each of the first IED and the second IED is a CPU board on which the first protection relay main calculation unit, the first protection relay fail-safe calculation unit, the second protection relay main calculation unit, and the second protection relay fail-safe calculation unit are mounted, The power system protection method includes: Each of the first IED and the second IED is Determine whether the CPU board included in itself is normal, When it is determined that the CPU board included in itself is abnormal, it outputs abnormality information to the other IED, If the CPU boards included in the first IED and the second IED are both normal, The first IED is The lock function locks the output of the accident determination result by the first protection relay fail-safe calculation unit and the second protection relay main calculation unit of the first IED, outputting a result of the fault determination by the first protection relay main calculation unit of the first IED to the first MU; outputting a result of the accident determination by the second protective relay fail-safe calculation unit of the first IED to the second MU; The second IED is The lock function locks the output of the accident determination result by the second protection relay fail-safe calculation unit and the first protection relay main calculation unit of the second IED, outputting a result of the fault determination by the second protection relay main calculation unit of the second IED to the second MU; A power system protection method, comprising: outputting a result of the accident determination by the first protective relay fail-safe calculation unit of the second IED to the first MU.

7. 7. The power system protection method according to claim 6, If the CPU board included in the first IED is abnormal, the first IED stops the accident determination by the first protection relay main calculation unit, the first protection relay fail-safe calculation unit, the second protection relay main calculation unit, and the second protection relay fail-safe calculation unit of the first IED, The second IED is unlocking the output of the accident determination by the lock function in the second protection relay fail-safe calculation unit and the first protection relay main calculation unit of the second IED; outputting a result of the fault determination by the second protection relay main calculation unit of the second IED to the second MU; outputting a result of the accident determination by the second protection relay fail-safe calculation unit of the second IED to the second MU; outputting a result of the fault determination by the first protection relay main calculation unit of the second IED to the first MU; A power system protection method, comprising: outputting a result of the accident determination by the first protective relay fail-safe calculation unit of the second IED to the first MU.

8. 7. The power system protection method according to claim 6, If the CPU board included in the second IED is abnormal, the second IED stops the accident determination by the first protection relay main calculation unit, the first protection relay fail-safe calculation unit, the second protection relay main calculation unit, and the second protection relay fail-safe calculation unit of the second IED, The first IED is unlocking the lock of the output of the accident determination by the lock function in the first protection relay fail-safe calculation unit and the second protection relay main calculation unit of the first IED; outputting a result of the fault determination by the first protection relay main calculation unit of the first IED to the first MU; outputting a result of the accident determination by the first protective relay fail-safe calculation unit of the first IED to the first MU; outputting a result of the fault determination by the second protection relay main calculation unit of the first IED to the second MU; A power system protection method, comprising: outputting a result of the accident determination by the second protective relay fail-safe calculation unit of the first IED to the second MU.

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