Protection system for DC railway substations

Abstract

To provide a protection system for a DC substation, capable of automatically changing a setting value of a protective relay.SOLUTION: A protection system comprises: an interlock breaking device for performing interlock breaking of breakers mutually coordinating between DC substations; and a protective relay that detects a ground fault current to open electrodes of the breakers, break a fault current, and protect substation equipment. The interlock breaking device includes: interlock breaking section change means for changing an interlock breaking section between the substations on the basis of establishment of a predetermined condition; means for transmitting a setting value change command for changing a setting value of a protective relay in an adjacent substation to an interlock breaking device of the adjacent substation; and means for transmitting a setting value change command received from an interlock breaking device of an adjacent substation to a corresponding protective relay via an extension adapter having a signal conversion function. When receiving the setting value change command, the protective relay outputs a setting value change completion signal to the corresponding interlock breaking device after a setting value is changed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technology that can be effectively used in a protection system for a DC railway substation (hereinafter referred to as a DC substation) for protecting substation equipment in the event of a power supply interruption at a DC railway substation that passes current to the DC feeder lines of an electric railway. [Background technology]

[0002] In DC substations that supply power to DC feeders of electric railways, protective relays constantly monitor the current and detect a sudden increase in current due to an accident such as a fire or a short circuit in the feeder circuit, thereby detecting a ground fault current and opening the electrodes of a circuit breaker to cut off the fault current.In addition, the feeding section of a DC substation where an accident such as a fire has occurred is isolated to prevent the accident from affecting the feeding sections of other adjacent DC substations.

[0003] Conventionally, an invention that isolates a substation when an accident occurs therein and limits the scope of the power outage to just the substation and its surrounding area is described, for example, in Patent Document 1. The invention in Patent Document 1 detects the occurrence of an accident when a busbar accident occurs while the busbar protection relay is out of function, opens the busbar tie-breaker (interrupts the current), and opens all breakers connected to the busbar on which it is determined that an accident has occurred.

[0004] Furthermore, some protective relays in DC substations have a function that stores multiple setting values ​​(current values ​​at which a fault is determined to have occurred) in memory and changes the setting value in response to an external command. Setting the setting value too low can cause malfunctions during normal vehicle powering operation, while setting it too high can prevent fault currents from being detected, so it is necessary to set the setting value appropriately. Patent Document 2, for example, describes a conventional invention that allows the setting values ​​of protective relays in a substation to be changed simultaneously from a distance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-3818 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-219943 Summary of the Invention [Problem to be solved by the invention]

[0006] In past fires at DC substations, the DC voltage (1500V) in the DC feeding section could not be supplied, resulting in problems that affected train operations. When a problem at a DC substation makes it impossible to supply power, the feeder line is disconnected from the substation, but this can cause an arc due to a potential difference in the air section installed near the substation. Therefore, in recent years, measures have been taken to prevent arcs from occurring by installing section short-circuit disconnectors, which allows power to be supplied to trains so that trains can continue to operate.

[0007] Furthermore, by installing and using a section short-circuit disconnector, it is possible to extend the interval between power outages at the substation and ensure sufficient time for work, which is expected to contribute to ensuring safe work.However, when this technology is adopted, the feeding configuration will change, and in order to expand the protection range of the protective relays at adjacent substations, it will be necessary to change the setting values ​​of the protective relays to lower their sensitivity, and to change the communication circuit configuration of the communication interrupter at that substation.Therefore, if no measures are taken, there is the issue that the response will actually require more manpower and time.

[0008] The invention described in Patent Document 1 is a protection technology that isolates the fault point by comparing the impedance values ​​of busbars and minimizes the scope of the impact, but in electric railway DC feeding systems, it is necessary to change the connection break section or setting values ​​after isolating the fault point, but there is no mention of this.Furthermore, the invention described in Patent Document 2 provides a technology for changing the setting values ​​of protective relays all at once from a distance, but there is no mention of automatic setting value changes that take into account changing conditions such as the shutdown of connection breakers when trouble occurs in a DC substation.

[0009] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a protection system for a DC substation that can automatically change the setting values ​​and the connection / disconnection section in consideration of change conditions such as the shutdown of the connection / disconnection device due to the occurrence of a problem in the DC substation, thereby eliminating the manpower and time required for the change. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides: A protection system comprising a contact breaker device for connecting and breaking circuit breakers interconnected between opposing DC substations, and a protective relay provided at each of the DC substations for detecting a ground fault current and opening electrodes of the circuit breaker to break the fault current, thereby protecting substation equipment from the fault current, The communication cutoff device is a disconnection section changing means for changing a disconnection section between the DC substations based on the establishment of a predetermined condition; a means for transmitting a setting value change command to change a setting value in a protective relay of an adjacent DC substation to a breaker device of the adjacent DC substation; means for transmitting a setting value change command received from the interlocking breaker of the adjacent DC substation to a corresponding protective relay via an expansion adapter having a function of converting a plurality of signals into a code with a number of bits smaller than the number of the signals; The protective relay that has received the setting value change command has means for outputting a setting value change completion signal to the corresponding communication cutoff device after changing the setting value.

[0011] According to a protection system having the above-described configuration, the system is equipped with a means for changing the connection cutoff section and a means for transmitting a setting value change command received from the connection cutoff device of an adjacent substation to the corresponding protection relay, so that it is possible to continue appropriate protection even if the substation trips due to an accident or is shut down due to work, and the setting values ​​and connection circuit configuration can be changed automatically without the need for manpower, eliminating the manpower and time required for changes. Furthermore, since the setting value change command is sent to the protective relay via an expansion adapter with a code conversion function, when applied to an existing protection system, it can be accommodated by simply adding an expansion adapter with a signal conversion function to the contact breaking device, and there is no need to significantly modify the contact breaking device, thereby suppressing the increase in costs associated with adding functions.

[0012] Here, preferably, a disconnector for section short-circuiting is provided in parallel with an air section provided in a feeder line receiving DC power from the substation equipment for each of the DC substations; The connection cutoff section changing means The circuit breaker is configured to operate when a condition for closing the disconnecting switch or a condition for stopping the circuit breaker from cutting off is met in any of the DC substations. As a result, the disconnection section changing means operates to change the disconnection section depending on the conditions of closing a section short-circuiting disconnecting switch or stopping the disconnection of the disconnection device in any of the substations, so the disconnection section can be changed automatically without requiring human intervention. Also, by providing and closing a section short-circuiting disconnecting switch, it is possible to extend the power outage interval at the substation and ensure sufficient time for work. Note that the closing of a section short-circuiting disconnecting switch is performed when all circuit breakers in the substation are in a current-interrupting state.

[0013] Furthermore, preferably, the connection cutoff section changing means is configured to operate when either the condition for opening the disconnector or the condition for restarting connection cutoff by the connection cutoff device is met. According to this configuration, the disconnected section that has been changed by turning on the disconnector for short-circuiting the section or by stopping the disconnection of the disconnection device can be automatically restored without requiring human intervention.

[0014] Also, preferably, the interconnection breaking device of the adjacent DC substation is a display means for displaying that the setting value change completion signal has not been received when the setting value change completion signal has not been received from the protective relay that has transmitted the setting value change command; The expansion adapter is configured to include means for outputting a setting value change disable signal that operates the display means in response to failure to receive the setting value change completion signal. With this configuration, it is possible to know that the setting value of the protective relay has not been changed, and it is possible to prevent the disconnection section from being changed without changing the protection range.

[0015] Furthermore, another invention of the present application is A protection system comprising: a contact breaker device for connecting and breaking circuit breakers interconnected between opposing DC substations; and a protective relay provided at each of the DC substations for detecting a ground fault current and opening electrodes of the circuit breaker to break the fault current, thereby protecting substation equipment from the fault current, The communication cutoff device is a detection means for detecting a failure in a communication line between the communication line and the communication cutoff device of an adjacent DC substation; means for outputting a setting value change command upon detection of a failure in the communication line; means for transmitting the setting value change command to the corresponding protective relay; The protective relay that receives the setting value change command The device has means for outputting a setting value change completion signal to the corresponding communication cutoff device after changing the setting value.

[0016] According to the protection system having the above configuration, the setting values ​​and the configuration of the communication circuit can be changed automatically without human intervention, eliminating the manpower and time required for the change. Also, when the communication line between the communication cutoff devices is broken, the communication cutoff section change means operates to change the communication cutoff section, thereby preventing power from being generated due to an inappropriate protection range setting.

[0017] Also, preferably, the communication cutoff device is a display means for displaying that the setting value change completion signal has not been received when the setting value change completion signal has not been received from the protection relay that has received the setting value change command; and means for outputting a setting value change disable signal that operates the display means in response to the setting value change completion signal not being received. With this configuration, it is possible to know that the setting value of the protective relay has not been changed, thereby preventing the disconnection section from being changed without changing the protection range. [Effects of the Invention]

[0018] According to the DC substation protection system of the present invention, it is possible to automatically change the setting values ​​and the connection / disconnection section taking into account change conditions such as the shutdown of the connection / disconnection device due to the occurrence of a problem in the DC substation, thereby eliminating the need for personnel and time required for the change. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a system configuration diagram showing an example of the configuration of a protection system for a DC substation according to the present invention; [Figure 2] FIG. 2 is a diagram illustrating the relationship between a setting value and a protection range in the protection system of the embodiment. [Figure 3] 10 is a diagram showing an operation procedure of the connection breaker device when a section short-circuiting disconnector is turned on in the protection system of the embodiment. FIG. [Figure 4] 10 is a diagram showing an operation procedure of the interconnection breaker device when an interconnection breaker stop is performed in association with inspection work of a DC substation in the protection system of the embodiment. FIG. [Figure 5] 10 is a diagram illustrating an operation of the connection cutoff device when a line failure occurs between the connection cutoff devices in the protection system of the embodiment. FIG. [Figure 6] 10 is a flowchart illustrating an example of a processing procedure performed by an arithmetic and logic controller of a communication cutoff device that constitutes the protection system of the embodiment. [Figure 7] 10 is a block diagram showing a specific example of signals input and output between the contact cutoff device, the expansion adapter, and the protective relay. FIG. [Figure 8] FIG. 10 is a diagram illustrating an example of a code table showing the relationship between inputs and outputs of an expansion adapter. [Figure 9] FIG. 1 is a system configuration diagram showing an example of the configuration of a conventional protection system. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of a protection system between DC substations according to the present invention will be described in detail with reference to the drawings. Fig. 1 is a diagram showing a schematic configuration of a protection system for a DC substation (hereinafter simply referred to as a substation) according to this embodiment. In Fig. 1, 10A, 10B, and 10C are substation equipment of substations A, B, and C, W1 and W2 are DC feeders in the substation to which DC power is supplied from substation equipment 10B, and W3 and W4 are DC feeders in the substation to which DC power is supplied from substation equipment 10A and 10C, respectively. In addition, substations A, B, and C are provided with breaker devices 30A, 30B, and 30C corresponding to substation equipment 10A, 10B, and 10C.

[0021] As shown in FIG. 1, substation equipment 10B is provided with AC transformers 11a, 11b, 11c, and 11d, rectifiers 12a, 12b, 12c, and 12d, DC high-speed circuit breakers (hereinafter referred to as circuit breakers) 13a, 13b, 13c, and 13d, current detectors 14a, 14b, 14c, and 14d that detect currents flowing to DC feeders, and protective relay (50F) 15 that detects ground fault currents based on voltages converted by the current detectors 14a, 14b, 14c, and 14d. Of the devices shown in Figure 1, those with suffixes a and b are for regular use (normal use), and those with suffixes c and d are for shared use (standby use). To switch between regular and shared use devices, disconnectors 16a and 16b are provided between current detectors 14c and 14d on the shared side and DC feeders W1 and W2. If circuit breaker 13a or 13b is tripped, the corresponding disconnector 16a or 16b is closed to allow current to flow through circuit breakers 13c and 13d, thereby enabling continuous power supply. Note that substation equipment 10A and 10C have a similar configuration to that described above, and therefore will not be illustrated or described here.

[0022] The protective relay 15 is configured to open the circuit breakers 13a to 13d when it detects a fault current in the feeding section, thereby cutting off the current sent to the DC feeders W1 and W2, and the set value (the current value that opens the circuit breakers 13a to 13d) is set so that the protection range covers, for example, 60% or more of the distance from the substation. Furthermore, the protective relay 15 has a memory for storing setting values ​​and a function for switching the setting values ​​in response to external commands. This is because when the transmission section is extended due to the implementation of extended power feeding, the protection range changes, and therefore the setting values ​​must be changed. The protective relay 15 is configured so that setting values ​​can be set separately for each of the circuit breakers 13a to 13d.

[0023] 1, W11 and W12 are in-track feeders laid along the railway track, with one end of each connected to feeders W1 and W2 in substation B and receiving DC power from substation equipment 10B. The other ends of in-track feeders W11 and W12 are connected to feeders W3 and W4 in substation A and substation C, respectively. In addition, an air section 21 is provided at the boundary between the in-track feeders W11 and W12, and a section short-circuiting disconnector 22 and its control device 23 are provided in parallel with this air section 21, and the feeders W11 and W12 are disconnected or connected depending on whether the section short-circuiting disconnector 22 is opened or closed.

[0024] The control device 23 is configured to close the section short-circuit disconnector 22 upon receiving a disconnector closing command signal from a control center (not shown), and to transmit a closing completion signal to the interconnection breaker device 30B. Fig. 9 shows an example of the configuration of a conventional protection system. As can be seen from a comparison of Fig. 1 and Fig. 9, the protection system of this embodiment differs in that the section short-circuit disconnector 22, its control device 23, and expansion adapters 32A, 32B, and 32C are added, and the interconnection breaker devices 30A, 30B, and 30C are provided with an interconnection breaker stop button and a test switch button.

[0025] In the protection system shown in Figure 1, if an accident occurs somewhere in substation B and either current detector 14a or 14b detects a ground fault current, protective relay 15 receives the output of current detector 14a or 14b and operates to open the electrodes of circuit breakers 13a and 13b, thereby interrupting the current. In this way, the fault section is isolated, and the impact of an accident occurring at substation B on the equipment at substations A and C can be reduced. In addition, when the circuit breakers 13a and 13b in substation B are shut off and the substation equipment 10B is disconnected from the feeder line, the control device 23 switches the section short-circuit disconnector 22 to the on state, and the feeder lines W11 and W12 are connected, enabling extended feeding that allows train operation.

[0026] Furthermore, in this embodiment, each of the substations A, B, and C is provided with a communication interruption device 30A, 30B, and 30C for interconnecting and interrupting the circuit breakers between the opposing substations, and the communication interruption devices 30A, 30B, and 30C of adjacent substations are connected to each other via signal cables 31A and 31B such as optical cables so that communication is possible. Then, through communication between the communication interruption devices 30A, 30B, and 30C (hereinafter simply referred to as "30" when not distinguished), a command to shut off the circuit breaker 13 by the protective relay 15 is sent to the communication interruption device 30 of the adjacent substation, and a command to change the setting value of the protective relay 15 is sent to the communication interruption device 30 of the opposing substation. As a result, if either of the protective relays 15 of adjacent substations detects a fault current, the interconnection breaker 30 will interrupt the current in the circuit breaker of the opposing substation, and if the transmission section is extended due to an extended power feeder, etc., the setting value can be automatically changed to expand the protection range. In conventional protection systems, the setting value of the protective relay 15 in such cases had to be changed manually.

[0027] Furthermore, when a substation is inspected, the circuit breaker 13 is shut off, and in order to prevent a shutoff command from being sent to an adjacent substation by mistake, an interconnection shutdown is performed in which the operation of the interconnection shutdown device 30 of the substation is stopped to cut off communication between the substations. In conventional protection systems, when an interconnection shutdown occurs and the protective relay 15 of one of the opposing substations operates, the circuit breaker 13 of the other substation is shut off by manual operation from the control center. In contrast, in the protection system of this embodiment, when communication between the intercommunication cutoff devices 30 of the opposing substations is cut off by operating the intercommunication cutoff stop button provided on the intercommunication cutoff device 30 to stop the intercommunication cutoff, the intercommunication cutoff device 30 is configured to switch the setting value of the protective relay 15 at its own discretion in the direction of extending the protection range.

[0028] Furthermore, in this embodiment, when the control device 23 closes the section short-circuit disconnector 22 in response to a command from the control center after disconnecting the substation equipment from the feeder, it transmits a signal informing the corresponding substation of the disconnector closing, and when the disconnector 30 receives this signal, it transmits a command to change the setting value of the circuit breaker 13 to the interconnector 30 of the adjacent substation. As a result, for example, in the power transmission system shown in Figure 1, when substation B is disconnected, because setting value 1 (e.g., 3000 A) was set so that the protection range between substations A and B and between substations B and C was 60% or more before the disconnection as shown in Figure 2(A), an unprotected range will occur unless some measures are taken, as shown in Figure 2(B).

[0029] Therefore, after separation, as shown in Figure 2(C), setting value 2 (for example, 2500A) is set so that the protection range between substations A and C is 60% or more. As a result, the entire transmission section of each substation is protected, making it possible to extend the power supply so that trains can continue operating. In Figure 2, the vertical axis represents the fault current and the horizontal axis represents the distance, and it shows that even for the same magnitude of fault current, the current value seen from protective relay 15 decreases as the distance from the substation increases. Furthermore, the communication cutoff device 30 of this embodiment has a line fault detection function, and is configured to automatically change the setting value of the protective relay 15 of the corresponding substation when a fault in the communication line is detected.

[0030] In addition, expansion adapters 32A, 32B, and 32C having code conversion functions are connected to the contact breakers 30A, 30B, and 30C, respectively, and are configured to be able to send setting value change commands to the protective relays 15 in the equipment 10A, 10B, and 10C of adjacent substations via the expansion adapters 32A, 32B, and 32C. Furthermore, each of the communication interruption devices 30A, 30B, and 30C is provided with a test switch and an operation button for switching to test mode, and when this test switch is turned on, it has the function of checking communication with the communication interruption device of an adjacent substation and the function of invalidating communication interruption commands and setting value change commands during test mode.

[0031] Next, the following will be described in order using Figures 3 to 5: the function of extending the protection range by changing the setting value of the protective relay 15 when the section short-circuit disconnector 22 is turned on or off, i.e., when an extended power feed occurs, which is a feature of the interconnection cutoff device 30 of this embodiment; the function of changing the setting value when the interconnection cutoff device 30 is turned on or off; and the function of changing the setting value when a line fault is detected. FIG. 3 shows the operation when the section short-circuiting disconnector 22 is turned on due to a trouble in the substation. Figure 3(A) shows the state before a substation trips, in which current is being sent from each of substations A, B, and C to feeders W11 and W12, respectively. The setting values ​​of circuit breakers 13 at substations A, B, and C are set to a value (e.g., 3000 A) that protects 60% of the section up to the adjacent substation.

[0032] In this state, when an accident or the like occurs within the substation and substation B trips, circuit breaker 13 is released, and a disconnecting switch closing command signal is sent from the control center to control device 23, control device 23 switches section short-circuiting disconnecting switch 22 to the closed state. Then, as shown by circled numbers 1 to 4 in Fig. 3(B), a signal indicating that section short-circuiting disconnecting switch 22 has been closed is first input from control device 23 to interconnection breaker 30B (step 1), and when interconnection breaker 30B receives this signal, it transmits a setting value change command to interconnection breakers 30A and 30C of adjacent substations A and C (step 2). Then, the intercom breaker devices 30A, 30C send a command to the corresponding protective relays 15A, 15C to change the setting value (step 3). Then, the protective relays 15A, 15C change the setting value to a value that widens the protection range (for example, 2500A), and then return a setting value change completion signal to the intercom breaker devices 30A, 30C (step 4). This allows the intercom breaker device 30B to perform response confirmation.

[0033] After that, substations A and C perform extended power feeding, the tie-break section is changed, and communication begins between tie-breaking devices 30A and 30C. At this time, tie-breaking device 30B functions as a communication repeater. Then, in this state, when a fault current is detected at either substation A or C and protective relay 15A or 15C opens the circuit breaker, tie-breaking device 30A or 30C transmits a tie-breaking command to the opposing tie-breaking device 30C or 30A. In addition, when the disconnector 22 that has been turned on is opened, the contact breaker 30B sends a change command to the contact breakers 30A and 30C of the adjacent substations A and C to restore the set value, and the protection range of the protective relay is changed (reduced) and the contact breaker section is changed.

[0034] Figure 4 shows the changes in operating conditions when a continuous shutdown is performed during substation inspection work. Figure 4(A) shows the state before work, in which current is being sent from each of substations A, B, and C to feeders W11 and W12, respectively, and the setting values ​​of circuit breakers 13 at substations A, B, and C are set to a value (e.g., 3000 A) that protects 60% of the section up to the adjacent substation. In this state, when the electrodes of the circuit breaker 13 in the substation equipment 10B are released for the purpose of inspecting the equipment in the substation B, etc., and then the interlock stop button provided on the interlocking device 30B is pressed, the interlocking device 30B sends a setting value change command to the interlocking devices 30A and 30C of the adjacent substations A and C, as shown in Figure 4(B) (Step 1).

[0035] Then, the intercom breaker devices 30A and 30C send a command to change the setting value to the corresponding protective relays 15A and 15C (step 2). Then, the protective relays 15A and 15C change the setting value to a value (e.g., 2500A) that widens the protection range as shown in Fig. 2(C), and then return a setting value change completion signal to the intercom breaker devices 30A and 30C, and the intercom breaker device 30B confirms the response (step 3). Thereafter, the communication breaker device 30B of the substation B stops operating, and as shown in FIG. 4(C), the substation B enters a communication breaker stopped state in which communication cannot be performed between the communication breaker devices 30A and 30C. In addition, when the interlock stop switch is turned off and interlocking is resumed, the interlocking device 30B sends a change command to the interlocking devices 30A and 30C of the adjacent substations A and C to restore the set values, and the protection range of the protective relay is changed (reduced) and the interlocking section is changed.

[0036] FIG. 5 shows the change in operating state when a communication line failure occurs. Figure 5(A) shows a state in which current is being sent from each substation A, B, and C to the feeders W11 and W12, respectively, and communication between the interconnection breakers 30A, 30B, and 30C is normal, and the setting values ​​of the circuit breakers 13 at substations A, B, and C are set to a value (e.g., 3000 A) that protects 60% of the section up to the adjacent substation. In this state, if communication between the interconnection cutoff devices 30A, 30B, and 30C becomes impossible, the interconnection cutoff devices 30A, 30B, and 30C each detect a failure in the communication line. Then, as shown in Figure 5(B), the interconnection cutoff devices 30A, 30B, and 30C each send a command to change the setting value to the corresponding protective relays 15A, 15B, and 15C of their own substations, and change the setting value of the protective relays 15A and 15C to a value (e.g., 2500A) that expands the protection range.

[0037] The communication cutoff devices 30A, 30B, and 30C can be configured by a device having a configuration similar to that of a general computer device (PC), which includes a programmable arithmetic processing unit such as a microprocessor (MPU) and storage means such as ROM (read only memory) and RAM (randomly readable and writable memory), input / output means for inputting and outputting signals, communication means for transmitting and receiving signals to and from other devices, etc. The above-mentioned processing is performed by the MPU of the communication cutoff devices 30A, 30B, and 30C executing a program stored in the memory. The above-mentioned functions added to the communication cutoff device 30 of this embodiment are realized by inserting a circuit board configured to have the above-mentioned additional functions on a single board into an empty slot of the device and connecting an expansion adapter 32 having a code conversion function.This allows the present invention to be applied without significantly improving the existing communication cutoff device 30, and reduces the cost increase associated with adding functions.

[0038] Next, an example of a processing procedure for realizing the above function by the arithmetic and control unit of the communication cutoff device 30 will be described with reference to the flowchart shown in FIG. 6, the calculation control unit of the interconnection breaker 30 first determines whether or not it has received a tripping execution signal indicating that the circuit breaker 13 has been opened from the protective relay 15 of its own substation (step S1). If it determines that it has received the tripping execution signal (YES), it proceeds to step S2 and transmits an interconnection break command signal to the interconnection breaker 30 of the adjacent substation to command it to open the circuit breaker and interrupt the current. At this time, if the protective relay 15 of its own substation opens the circuit breaker on the upstream side, it transmits an interconnection break command to the interconnection breaker 30 of the adjacent substation on the upstream side, and if the protective relay 15 of its own substation opens the circuit breaker on the downstream side, it transmits an interconnection break command to the interconnection breaker 30 of the adjacent substation on the downstream side.

[0039] The calculation control unit then determines whether or not a tie breaking command has been received from the tie breaking device 30 of the adjacent substation (step S3). If it determines that a tie breaking command has been received (YES), it proceeds to step S4 and transmits a tie breaking command signal to the protective relay 15 of its own substation to open the circuit breaker and interrupt the current. At this time, if a tie breaking command has been received from the tie breaking device 30 of the adjacent substation in the upstream direction, it transmits a tie breaking command signal to open the circuit breaker on the upstream side, and if a tie breaking command has been received from the tie breaking device 30 of the adjacent substation in the downstream direction, it transmits a tie breaking command signal to open the circuit breaker on the downstream side.

[0040] Next, the calculation control unit determines whether or not it has received a closing signal for the section short-circuit disconnecting switch 22 corresponding to its own substation (step S5). If it determines that it has received a disconnecting switch closing signal (YES), it proceeds to step S7 and transmits a setting value change command to the interconnection breaking devices 30 of both the upstream and downstream adjacent substations. If it determines in step S5 that it has not received a disconnecting switch closing signal (NO), it proceeds to step S6 and determines whether or not the interconnection breaking stop switch has been turned on. If it determines that the interconnection breaking stop switch has been turned on (YES), it proceeds to step S7 and transmits a setting value change command to the interconnection breaking devices 30 of both the upstream and downstream adjacent substations, and then stops operation.

[0041] If it is determined in step S6 that the interlocking stop switch is not on (NO), the calculation control unit proceeds to step S8, where it checks the communication line with the interlocking device 30 of the adjacent substation, and determines whether or not there is an abnormality in the communication line (step S9). If it is determined here that there is an abnormality in the communication line (YES), it proceeds to step S11, where it outputs a line fault signal to the expansion adapter 32. At this time, if a communication abnormality with the interlocking device 30 of the adjacent substation in the upstream direction is detected, it outputs a signal indicating a line fault on the upstream side, and if a communication abnormality with the interlocking device 30 of the adjacent substation in the downstream direction is detected, it outputs a signal indicating a line fault on the downstream side.

[0042] On the other hand, if it is determined in step S9 that there is no abnormality in the communication line (NO), the process proceeds to step S10, where it is determined whether or not a setting value change command has been received from the interconnection breaking device 30 of the adjacent substation. If it is determined that a setting value change command has been received (YES), the process proceeds to step S11, where a sensitivity change signal is output to the expansion adapter 32. At this time, if a setting value change command has been received from the interconnection breaking device 30 of the adjacent substation in the up direction, a signal indicating a change in sensitivity on the down side is output, and if a setting value change command has been received from the interconnection breaking device 30 of the adjacent substation in the down direction, a signal indicating a change in sensitivity on the up side is output. Thereafter, the process returns to step S1, and the above processing is repeated.

[0043] FIG. 7 shows a specific example of signals input and output between the contact breaker device 30, the expansion adapter 32, and the protective relay 15. As shown in Fig. 7, four signals 1Z to 4Z related to sensitivity change commands (setting value designation), an uplink sensitivity change command signal, a downlink sensitivity change command signal, a signal indicating a line fault in the uplink direction, and a signal indicating a line fault in the downlink direction are input from the connection breaker device 30 to the expansion adapter 32. Of these signals, 1Z to 4Z are the same signals as in the existing system, while the other signals are new signals. The four signals 1Z to 4Z are present so that setting values ​​can be designated for each of the four uplink and downlink, regular and shared circuit breakers 13a to 13d.

[0044] The signals 1Z to 4Z are signals that indicate setting value 1 when they are logic "0" and that indicate setting value 2 when they are logic "1", for example. In addition, the intercommunication breaking device 30 directly outputs a signal to the protective relay 15 to command the disconnection of the upstream side circuit breaker and a signal to command the disconnection of the downstream side circuit breaker, and the protective relay 15 is configured to return a disconnection execution signal to the intercommunication breaking device 30 when the disconnection of the circuit breaker is completed, and a setting value completion signal when the change of the circuit breaker setting value is completed.

[0045] The expansion adapter 32 converts the eight 1-bit signals into 4-bit binary code signals 1ZC to 4ZC and outputs them to the protection relay 15. When the protection relay 15 has successfully changed the setting value, it returns a change response signal indicating completion of the change to the expansion adapter 32. The expansion adapter 32 also has a fault determination function, and is configured to output an equipment fault signal and display "fault" on the display 33 if a change response signal is not returned from the protection relay 15 after outputting a sensitivity change command signal.

[0046] FIG. 8 shows an example of a code table showing the relationship between the input and output of the expansion adapter 32. In the code table in FIG. 8, "No Z" indicates that all circuit breakers are targeted without specifying an individual circuit breaker; "1Z" through "4Z" indicate that one of circuit breakers 13a through 13d is targeted; "Normal Setting" indicates that setting value 1 (normal use), which has a narrower protection range, is set; and "Expanded" indicates that setting value 2 (common use), which has a wider protection range, is set. In other words, in the code table in FIG. 8, "0" in the 4Z through 1Z and 4ZC through 1ZC columns indicates that the protection range is normal (no expansion); "1" indicates that the protection range is expanded. Furthermore, "1" in the "Upstream / Downstream Sensitivity Change / Line Fault" column indicates that the sensitivity change or line fault condition is met, and "0" indicates that the condition is not met. The "HEX" in the rightmost column indicates the hexadecimal representation of the 4-bit output codes 1ZC through 4ZC.

[0047] Also, as shown in Fig. 7, the uplink / downlink sensitivity change command signal and the uplink / downlink line fault signal are separate signals, but the same output code is generated for the uplink sensitivity change command signal and the uplink line fault signal, and the same output code is generated for the downlink sensitivity change command signal and the downlink line fault signal, so in Fig. 8 the sensitivity change command and line fault are integrated for the uplink and downlink, respectively, and shown as the uplink sensitivity change line fault signal and the downlink sensitivity change line fault signal. Note that the code table in Fig. 8 is an example and is not limited to this.

[0048] In addition, the expansion adapter 32 is provided with a switch SW for indicating whether or not to use the adapter, and when the switch SW is turned on, the above-mentioned code conversion operation is performed, and when the switch SW is not turned on, the signals 1Z to 4Z from the contact cutoff device 30 are output directly to the protective relay 15. The expansion adapter 32 can be configured with a plurality of relays and a device called a PLC (Programmable Logic Controller) that can configure a relay circuit having any logic function.

[0049] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, in the above-described embodiments, the breaker command for the circuit breaker 13 in the substation is sent directly from the intercom breaker device 30 to the corresponding protective relay 15, and the break execution signal is sent from the protective relay 15 to the intercom breaker device 30. However, these signals may also be sent and received via the expansion adapter 32. In addition, in the above embodiment, the expansion adapter 32 is provided with a means for outputting a signal to operate the display 33 in response to the communication cut-off device 30 not receiving a setting value change completion signal, but such a means may also be provided in the communication cut-off device 30.

[0050] Furthermore, in the above embodiment, the setting value of the protective relay 15 is configured to be settable in two stages, but it may be configured to be settable in three or more stages. In addition, in the above embodiment, the disconnector 22 arranged in parallel with the air section 21 is configured to be able to be operated remotely, but a manual disconnector may also be used, in which case a detector that detects the on state of the disconnector may be provided instead of the control device 23, and the detection signal may be supplied to the corresponding communication cutoff device 30 as a disconnector on signal. [Explanation of symbols]

[0051] 10A, 10B, 10C substation equipment 11a, 11b, 11c, 11d AC transformers 12a,12b,12c,12d rectifier 13a, 13b, 13c, 13d DC high-speed circuit breaker 14a, 14b, 14c, 14d Current detector 15 Protective relay 16a,16b Disconnector 21 Air Section 22 Section short-circuit disconnector 23 Control device 30, 30A, 30B, 30C Interconnection breaker 31A, 31B signal cable 32, 32A, 32B, 32C expansion adapter 33 Display W1, W2 DC feeder in substation W11, W12 DC feeder in track

Claims

1. A protection system comprising: a contact breaker device for connecting and breaking circuit breakers interconnected between opposing DC substations; and a protective relay provided at each of the DC substations for detecting a ground fault current and opening electrodes of the circuit breaker to break the fault current, thereby protecting substation equipment from the fault current, a disconnector for section short-circuiting is provided in parallel with an air section provided in a feeder line receiving DC power from the substation equipment for each of the DC substations; The communication cutoff device is a disconnection section changing means for changing a disconnection section between the DC substations based on the establishment of a predetermined condition; a means for transmitting a setting value change command to change a setting value in a protective relay of an adjacent DC substation to a breaker device of the adjacent DC substation; means for transmitting a setting value change command received from the interlocking breaker of the adjacent DC substation to a corresponding protective relay via an expansion adapter having a function of converting a plurality of signals into a code with a number of bits smaller than the number of the signals; The protective relay that has received the setting value change command has means for outputting a setting value change completion signal to the corresponding communication cutoff device after changing the setting value, The connection cutoff section changing means A protection system characterized by being activated when a condition for either closing the disconnecting switch or stopping the disconnection of the disconnection device is met in any of the DC substations.

2. 2. The protection system according to claim 1, wherein the connection cutoff section change means operates when one of the conditions for opening the disconnector or for restarting the connection cutoff of the connection cutoff device is met.

3. The interconnection breaking device of the adjacent DC substation, a display means for displaying that the setting value change completion signal has not been received when the setting value change completion signal has not been received from the protective relay that has transmitted the setting value change command; 3. The protection system according to claim 1, wherein the expansion adapter is provided with a means for outputting a setting value change impossible signal that causes the display means to operate in response to failure to receive the setting value change completion signal.

4. A protection system comprising: a contact breaker device for connecting and breaking circuit breakers interconnected between opposing DC substations; and a protective relay provided at each of the DC substations for detecting a ground fault current and opening electrodes of the circuit breaker to break the fault current, thereby protecting substation equipment from the fault current, The communication cutoff device is a detection means for detecting a failure in a communication line between the communication line and the communication cutoff device of an adjacent DC substation; means for outputting a setting value change command upon detection of a failure in the communication line; means for transmitting the setting value change command to the corresponding protective relay; The protective relay that receives the setting value change command A protection system comprising means for outputting a setting value change completion signal to the corresponding communication cutoff device after changing a setting value.

5. The communication cutoff device is a display means for displaying that the setting value change completion signal has not been received when the setting value change completion signal has not been received from the protection relay that has received the setting value change command; means for outputting a setting value change disable signal for operating said display means in response to failure to receive said setting value change completion signal; 5. The protection system of claim 4, further comprising:

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