Protection system and protection method for a substation

Abstract

The application discloses a protection system and a protection method of a transformer substation. The transformer substation comprises three circuit breakers which are sequentially connected between a first bus and a second bus, and a branch connected between two adjacent circuit breakers. The protection system of the transformer substation comprises a protection circuit corresponding to the branch, and the protection circuit comprises a three-phase voltage transformer, a first protection device, a second protection device, a measurement and control device, a first general switch, a second general switch, a first branch switch, a second branch switch and a third branch switch. The measurement and control device is used for judging whether to control the circuit breakers on both sides of the branch to be closed according to a first preset condition, and the first preset condition comprises whether there is voltage at the secondary side of the three-phase voltage transformer, whether the first general switch, the second general switch, the first branch switch, the second branch switch and the third branch switch are in the closed position, and whether the first protection device and the second protection device send a preset abnormal state signal. The technical scheme of the application is helpful to reduce the probability of misoperation accidents.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of power system, in particular to a protection system and a protection method of a substation. BACKGROUND

[0002] At present, the substation of 500kV voltage level generally applies two-thirds connection mode. For the protection and control of 500kV line and main transformer, the three-phase voltage transformer on the line side or the transformer side is generally adopted to realize. The protection function of the existing protection device of 500kV line and main transformer may appear misjudgment, causing protection misoperation accident, which is not conducive to the safe operation of the power grid. SUMMARY

[0003] The embodiment of the present application provides a protection system and a protection method of a substation, so as to reduce the probability of misoperation accident, thereby improving the safety of power grid operation.

[0004] In the first aspect, the embodiment of the present application provides a protection system of a substation, the substation comprising a first bus, a second bus and three circuit breakers connected in series between the first bus and the second bus, a branch being connected between two adjacent circuit breakers, the branch comprising a line branch or a main transformer branch; the protection system of the substation comprises: a protection circuit corresponding to each branch, the protection circuit comprising:

[0005] a three-phase voltage transformer connected to the corresponding branch, comprising a first secondary winding and a second secondary winding, each of the first secondary winding and the second secondary winding comprising a three-phase winding;

[0006] a first protection device, a first main switch and a first branch switch, each phase winding of the first secondary winding being connected to a phase input end of the first protection device through the first main switch and the first branch switch in turn;

[0007] a second protection device, a second main switch and a second branch switch, each phase winding of the second secondary winding being connected to a phase input end of the second protection device through the second main switch and the second branch switch in turn;

[0008] a third branch switch, an A-phase input end of the measuring and controlling device is connected to a first node through a third branch switch, the first node is located between the first total switch and the first branch switch corresponding to the A-phase winding of the first secondary winding, a B-phase input end of the measuring and controlling device is connected to a second node through a third branch switch, the second node is located between the first total switch and the first branch switch corresponding to the B-phase winding of the first secondary winding, and a C-phase input end of the measuring and controlling device is connected to a third node through a third branch switch, the third node is located between the first total switch and the first branch switch corresponding to the C-phase winding of the first secondary winding;

[0009] The measuring and controlling device is configured to determine whether to control the circuit breakers on both sides of the branch to close according to a first preset condition, and the first preset condition includes whether there is voltage on the secondary side of the three-phase voltage transformer, whether the first total switch, the second total switch, the first branch switch, the second branch switch and the third branch switch are in a closed position, and whether the first protection device and the second protection device send a preset abnormal state signal.

[0010] Optionally, the protection circuit further comprises:

[0011] a live display connected to the corresponding branch, configured to detect and display three-phase voltage of the branch;

[0012] a first voltage monitoring relay connected between the first total switch and the first node corresponding to the A-phase winding of the first secondary winding, between the first total switch and the second node corresponding to the B-phase winding of the first secondary winding, and between the first total switch and the third node corresponding to the C-phase winding of the first secondary winding;

[0013] a second voltage monitoring relay connected between the second total switch and the second branch switch corresponding to the A-phase winding of the second secondary winding, between the second total switch and the second branch switch corresponding to the B-phase winding of the second secondary winding, and between the second total switch and the second branch switch corresponding to the C-phase winding of the second secondary winding;

[0014] The first preset condition further includes whether the live display detects that there is voltage on the three phases of the branch, and the measuring and controlling device is further configured to detect the voltage of the first node, the second node and the third node to determine whether there is voltage on the secondary side of the three-phase voltage transformer, or to determine whether there is voltage on the secondary side of the three-phase voltage transformer according to signals of the first voltage monitoring relay and the second voltage monitoring relay.

[0015] Optionally, the preset abnormal state signal comprises an alarm signal, a lockout signal, a DC power supply voltage loss signal and a protection channel abnormal signal.

[0016] Optionally, the measurement and control device is configured to determine that the circuit breaker on the two sides of the branch is allowed to be closed manually or remotely when the first preset condition is met.

[0017] The first preset condition specifically comprises that the secondary side of the three-phase voltage transformer has voltage, the live display detects that all three phases of the branch have voltage, the first general switch, the second general switch, the first branch switch, the second branch switch and the third branch switch are all in the closed position, and the first protection device and the second protection device do not send an alarm signal, a lockout signal, a DC power supply voltage loss signal and a protection channel abnormal signal.

[0018] Optionally, the first preset condition specifically comprises that the secondary side of the three-phase voltage transformer has no voltage, the live display detects that all three phases of the branch have no voltage, the first general switch, the second general switch, the first branch switch, the second branch switch and the third branch switch are all in the closed position, and the first protection device and the second protection device do not send an alarm signal, a lockout signal, a DC power supply voltage loss signal and a protection channel abnormal signal.

[0019] Optionally, disconnecting switches are connected at both ends of each circuit breaker, the disconnecting switches connected to different circuit breakers are different, and the branch is connected between two disconnecting switches connected to adjacent circuit breakers.

[0020] The measurement and control device is further configured to determine that the circuit breaker on one side of the branch is allowed to be closed manually or remotely when a second preset condition is met, and the second preset condition comprises:

[0021] The disconnecting switches connected at both ends of the circuit breaker are in the open position, the motor power supply of the disconnecting switches connected at both ends of the circuit breaker is disconnected, the motor power supply of the disconnecting switches connected at both ends of the circuit breaker is additionally provided with a five-prevention isolation lock, and the circuit breaker is in a maintenance state.

[0022] Optionally, the measurement and control device comprises:

[0023] An equipment state acquisition module is configured to acquire the on / off state signals of the circuit breakers and disconnectors, the preset abnormal state signals of the first protection device and the second protection device, the voltage signals of the first node, the second node and the third node, the on / off state signals of the first total switch, the second total switch, the first branch switch, the second branch switch and the third branch switch, the motor power supply state signal of the disconnectors and the maintenance state signals of the first protection device and the second protection device.

[0024] An analog quantity acquisition module is configured to acquire single-phase voltages of the first busbar and the busbar, three-phase voltages, three-phase currents and zero-sequence currents of the branch.

[0025] A power conversion module is configured to convert an input power to supply power to the measurement and control device.

[0026] A control module is connected to the equipment state acquisition module, the analog quantity acquisition module, the power conversion module and the corresponding circuit breakers and disconnectors, and is configured to control the corresponding circuit breakers and disconnectors.

[0027] Optionally, the protection system of the substation further comprises a microcomputer five-prevention system, a monitoring system, an intelligent operation and maintenance system and a dispatching automation system; the measurement and control device is in communication connection with the microcomputer five-prevention system, the monitoring system, the intelligent operation and maintenance system and the dispatching automation system through the control module.

[0028] The measurement and control device is further configured to receive a control instruction of the monitoring system, the intelligent operation and maintenance system or the dispatching automation system, and execute the control instruction when the control instruction meets the locking requirement, so as to control the corresponding circuit breakers and disconnectors.

[0029] Optionally, at least one of the microcomputer five-prevention system, the monitoring system, the intelligent operation and maintenance system and the dispatching automation system is further configured to control each of the circuit breakers and the disconnectors.

[0030] In a second aspect, an embodiment of the present application provides a protection method of a substation, which is executed by a protection system of the substation.

[0031] The substation comprises a first busbar, a second busbar and three circuit breakers connected in series between the first busbar and the second busbar, and each two adjacent circuit breakers are connected with a branch, and the branch comprises a line branch or a main transformer branch; the protection system of the substation comprises a protection circuit corresponding to each branch, and the protection circuit comprises:

[0032] The three-phase voltage transformer is connected to the corresponding branch, and includes a first secondary winding and a second secondary winding, each of the first secondary winding and the second secondary winding includes a three-phase winding;

[0033] The first protection device, the first main switch and the first branch switch, each phase winding of the first secondary winding is connected to a phase input terminal of the first protection device through a first main switch and a first branch switch in sequence;

[0034] The second protection device, the second main switch and the second branch switch, each phase winding of the second secondary winding is connected to a phase input terminal of the second protection device through a second main switch and a second branch switch in sequence;

[0035] The measurement and control device and the third branch switch, the A-phase input terminal of the measurement and control device is connected to a first node through a third branch switch, the first node is located between the first main switch and the first branch switch corresponding to the A-phase winding of the first secondary winding, the B-phase input terminal of the measurement and control device is connected to a second node through a third branch switch, the second node is located between the first main switch and the first branch switch corresponding to the B-phase winding of the first secondary winding, the C-phase input terminal of the measurement and control device is connected to a third node through a third branch switch, the third node is located between the first main switch and the first branch switch corresponding to the C-phase winding of the first secondary winding;

[0036] The protection method of the substation includes:

[0037] The measurement and control device judges whether to control the closing of the circuit breakers on both sides of the branch according to a first preset condition, the first preset condition includes whether there is voltage on the secondary side of the three-phase voltage transformer, whether the first main switch, the second main switch, the first branch switch, the second branch switch and the third branch switch are in the closed position, and whether the first protection device and the second protection device send a preset abnormal state signal.

[0038] The protection system and protection method of the substation provided by the embodiment of the present application can be applied to a substation adopting two-thirds wiring, the substation comprising a first busbar, a second busbar and three circuit breakers connected in series between the first busbar and the second busbar, one branch being connected between each two adjacent circuit breakers, and a protection circuit being arranged for each branch, the protection circuit comprising a three-phase voltage transformer, a first protection device, a second protection device, a measurement and control device, a first main switch, a second main switch, a first branch switch and a second branch switch, and the measurement and control device in each protection circuit determines whether to control the circuit breakers on both sides of the corresponding branch to be closed according to whether there is voltage at the secondary side of the three-phase voltage transformer corresponding to the branch, whether the first main switch, the second main switch, the first branch switch, the second branch switch and the third branch switch are in the closed position, and whether the first protection device and the second protection device send a preset abnormal state signal, which helps to avoid misjudgment of the protection function of the branch, thereby reducing the probability of misoperation accidents and improving the safety of power grid operation.

[0039] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0041] Figure 1 is a two-thirds wiring schematic diagram of a substation provided by the embodiment of the present application;

[0042] Figure 2 is a structure schematic diagram of a protection circuit provided by the embodiment of the present application;

[0043] Figure 3 is a structure schematic diagram of a measurement and control device provided by the embodiment of the present application;

[0044] Figure 4 is a structure schematic diagram of a protection system of a substation provided by the embodiment of the present application. DETAILED DESCRIPTION

[0045] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely in conjunction with the drawings in the embodiments of the present application, so that those skilled in the art can better understand the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present application.

[0046] It should be noted that the terms "first", "second" and the like in the description and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0047] The embodiment of the present application provides a protection system of a substation. Figure 1 is a schematic diagram of a two-thirds wiring of a substation provided by the embodiment of the present application. Figure 2 is a structural schematic diagram of a protection circuit provided by the embodiment of the present application. In combination with Figure 1 and Figure 2 , the substation comprises a first bus 1M, a second bus 2M and three circuit breakers connected in sequence between the first bus 1M and the second bus 2M, and a branch 10 connected between adjacent two circuit breakers, the branch 10 comprising a line branch or a main transformer branch. The protection system of the substation comprises: a protection circuit corresponding to each branch 10. The protection circuit comprises: a three-phase voltage transformer PT, a first protection device 210, a second protection device 220, a measurement and control device 30, a first total switch, a second total switch, a first branch switch and a second branch switch.

[0048] The three-phase voltage transformer PT is connected to the corresponding branch 10, and the three-phase voltage transformer PT comprises a first secondary winding and a second secondary winding, and each phase winding of the first secondary winding and the second secondary winding comprises a three-phase winding. Each phase winding of the first secondary winding is connected to a phase input end of the first protection device 210 through a first total switch and a first branch switch in sequence. Each phase winding of the second secondary winding is connected to a phase input end of the second protection device 220 through a second total switch and a second branch switch in sequence.

[0049] The A-phase input end of the measuring and controlling device 30 is connected with the first node N1 through a third branch switch, the first node N1 is located between the first total switch and the first branch switch corresponding to the A-phase winding of the first secondary winding, the B-phase input end of the measuring and controlling device 30 is connected with the second node N2 through a third branch switch, the second node N2 is located between the first total switch and the first branch switch corresponding to the B-phase winding of the first secondary winding, and the C-phase input end of the measuring and controlling device 30 is connected with the third node N3 through a third branch switch, the third node N3 is located between the first total switch and the first branch switch corresponding to the C-phase winding of the first secondary winding.

[0050] The measuring and controlling device 30 is used for judging whether to control the closing of the circuit breakers on both sides of the branch 10 according to the first preset condition, and the first preset condition includes whether there is voltage on the secondary side of the three-phase voltage transformer PT, whether the first total switch, the second total switch, the first branch switch, the second branch switch and the third branch switch are in the closed position, and whether the first protection device 210 and the second protection device 220 send a preset abnormal state signal.

[0051] Specifically, the substation in the embodiment of the application can be a 500kV voltage grade substation, and the substation adopts a two-thirds connection mode. For convenience of distinction, the three circuit breakers connected in series between the first bus 1M and the second bus 2M are denoted as circuit breaker D1, circuit breaker D2 and circuit breaker D3. The branches 10 connected between two adjacent circuit breakers include branch 10a and branch 10b, the branch 10a is connected between the circuit breaker D1 and the circuit breaker D2, and the branch 10b is connected between the circuit breaker D2 and the circuit breaker D3. The branch 10a can be a branch connected with a 500kV line 110, hereinafter referred to as a 500kV line branch 10a, and the branch 10b can be a branch connected with a 500kV main transformer T, hereinafter referred to as a 500kV transformer branch 10b. The 500kV line branch 10a and the 500kV transformer branch 10b are respectively provided with corresponding protection circuits, Figure 2 The protection circuit shown can be a protection circuit of the 500kV line branch 10a or a protection circuit of the 500kV transformer branch 10b.

[0052] For the protection circuit of the 500kV line branch 10a, the characteristics are as follows:

[0053] The three-phase voltage transformer PT1 is connected to the 500 kV line branch 10a. The three-phase windings of the first secondary winding of the three-phase voltage transformer PT1 include an A-phase winding PT02a, a B-phase winding PT02b and a C-phase winding PT02c. The first protection device 210 can include three-phase input terminals. The A-phase winding PT02a is connected to the A-phase input terminal of the first protection device 210 through the first general switch 2CBa and the first branch switch ZKK1a in sequence. The B-phase winding PT02b is connected to the B-phase input terminal of the first protection device 210 through the first general switch 2CBb and the first branch switch ZKK1b in sequence. The C-phase winding PT02c is connected to the C-phase input terminal of the first protection device 210 through the first general switch 2CBc and the first branch switch ZKK1c in sequence. The three-phase windings of the second secondary winding of the three-phase voltage transformer PT1 include an A-phase winding PT03a, a B-phase winding PT03b and a C-phase winding PT03c. The second protection device 220 can include three-phase input terminals. The A-phase winding PT03a is connected to the A-phase input terminal of the second protection device 220 through the second general switch 3CBa and the second branch switch ZKK2a in sequence. The B-phase winding PT03b is connected to the B-phase input terminal of the second protection device 220 through the second general switch 3CBb and the second branch switch ZKK2b in sequence. The C-phase winding PT03c is connected to the C-phase input terminal of the second protection device 220 through the second general switch 3CBc and the second branch switch ZKK2c in sequence. The measurement and control device 30 can include three-phase input terminals. The A-phase input terminal of the measurement and control device 30 is connected to the first node N1 through the third branch switch ZKK3a. The first node N1 is located between the first general switch 2CBa and the first branch switch ZKK1a corresponding to the A-phase winding PT02a of the first secondary winding. The B-phase input terminal of the measurement and control device 30 is connected to the second node N2 through the third branch switch ZKK3b. The second node N2 is located between the first general switch 2CBb and the first branch switch ZKK1b corresponding to the B-phase winding PT02b of the first secondary winding. The C-phase input terminal of the measurement and control device 30 is connected to the third node N3 through the third branch switch ZKK3c. The third node N3 is located between the first general switch 2CBc and the first branch switch ZKK1c corresponding to the C-phase winding PT02c of the first secondary winding. The A-phase winding PT02a, the B-phase winding PT02b, the C-phase winding PT02c, the first general switches 2CBa to 2CBc, the A-phase winding PT03a, the B-phase winding PT03b, the C-phase winding PT03c and the first general switches 3CBa to 3CBc can be arranged in the same compartment 410.

[0054] Before being put into operation, the 500kV line branch 10a can be in a live state or a non-live state, and whether the 500kV line branch 10a has voltage can be determined according to whether there is voltage at the secondary side of the three-phase voltage transformer PT1. When any one of the circuit breakers D1 and D2 on the two sides of the 500kV line branch 10a is put into operation, as long as it is determined that the three phases of the 500kV line branch 10a all have voltage or all do not have voltage, and the first general switch 2CBa to 2CBc, the second general switch 3CBa to 3CBc, the first branch switch ZKK1a to ZKK1c, the second branch switch ZKK2a to ZKK2c and the third branch switch ZKK3a to ZKK3c corresponding to the 500kV line branch 10a are all in the closed position, and the first protection device 210 and the second protection device 220 do not send the preset abnormal state signal, it can be ensured that the first protection device 210 and the second protection device 220 will not malfunction. That is, whether the circuit breakers D1 and D2 on the two sides of the 500kV line branch 10a are controlled to be closed can be determined by the measurement and control device 30 according to the first preset condition, so as to avoid the corresponding first protection device 210 and the second protection device 220 from malfunctioning.

[0055] The protection circuit of the 500kV transformer branch 10b has a structure similar to that of the protection circuit of the 500kV line branch 10a, and the only difference is that the three-phase voltage transformer therein is the three-phase voltage transformer PT2 connected to the 500kV transformer branch 10b, and the specific structure will not be described again.

[0056] Before being put into operation, the 500kV transformer branch 10b can be in a live state or a non-live state, and whether the 500kV transformer branch 10b has voltage can be determined according to whether there is voltage at the secondary side of the three-phase voltage transformer PT2. When any one of the circuit breakers D2 and D3 on the two sides of the 500kV transformer branch 10b is put into operation, as long as it is determined that the three phases of the 500kV transformer branch 10b all have voltage or all do not have voltage, and the first general switch 2CBa to 2CBc, the second general switch 3CBa to 3CBc, the first branch switch ZKK1a to ZKK1c, the second branch switch ZKK2a to ZKK2c and the third branch switch ZKK3a to ZKK3c corresponding to the 500kV transformer branch 10b are all in the closed position, and the first protection device 210 and the second protection device 220 do not send the preset abnormal state signal, it can be ensured that the first protection device 210 and the second protection device 220 will not malfunction. That is, whether the circuit breakers D2 and D3 on the two sides of the 500kV transformer branch 10b are controlled to be closed can be determined by the measurement and control device 30 according to the first preset condition, so as to avoid the corresponding first protection device 210 and the second protection device 220 from malfunctioning.

[0057] In summary, the technical scheme of the embodiment of the present application can be applied to a substation adopting two-thirds wiring, the substation comprising a first bus, a second bus, and three circuit breakers connected in series between the first bus and the second bus, one branch being connected between each two adjacent circuit breakers, a protection circuit being arranged for each branch, the protection circuit comprising a three-phase voltage transformer, a first protection device, a second protection device, a measurement and control device, a first main switch, a second main switch, a first branch switch, and a second branch switch, the measurement and control device in each protection circuit judging whether to control the circuit breakers on both sides of the corresponding branch to be closed according to whether there is voltage at the secondary side of the three-phase voltage transformer corresponding to the branch, whether the first main switch, the second main switch, the first branch switch, the second branch switch, and the third branch switch are in the closed position, and whether the first protection device and the second protection device send a preset abnormal state signal, which helps to avoid misjudgment of the protection function of the branch, thereby reducing the probability of misoperation accidents and improving the safety of power grid operation.

[0058] In combination Figure 1 and Figure 2 On the basis of the above embodiment, optionally, the protection circuit further comprises a live display M, a first voltage monitoring relay YJS2, and a second voltage monitoring relay YJS3. The live display M is connected to the corresponding branch 10 and is used to detect and display the three-phase voltage of the branch 10. The live display M can be connected to the 500kV line branch 10a and the 500kV transformer branch 10b. Correspondingly, the first preset condition further comprises whether the live display M detects that all three phases of the branch 10 have voltage. The first voltage monitoring relay YJS2 is connected between the first main switch 2CBa corresponding to the A-phase winding PT02a of the first secondary winding, the first main switch corresponding to the B-phase winding PT02b of the first secondary winding, and the first main switch 2CBbc corresponding to the C-phase winding PT02c of the first secondary winding, the second node N2, and the third node N3. The second voltage monitoring relay YJS3 is connected between the second main switch 3CBa corresponding to the A-phase winding PT03a of the second secondary winding, the second branch switch ZKK2a, the second main switch 3CBb corresponding to the B-phase winding PT03b of the second secondary winding, the second branch switch ZKK2b, and the second main switch 3CBc corresponding to the C-phase winding PT03c of the second secondary winding, and the second branch switch ZKK2c. The measurement and control device 30 is further used to detect the voltage of the first node N1, the second node N2, and the third node N3 to judge whether there is voltage at the secondary side of the three-phase voltage transformer PT, or to judge whether there is voltage at the secondary side of the three-phase voltage transformer PT according to the signals of the first voltage monitoring relay YJS2 and the second voltage monitoring relay YJS3. The first voltage monitoring relay YJS2 and the second voltage monitoring relay YJS3 can both be arranged in the interface screen 420.

[0059] Optionally, the preset abnormal state signals of the first protection device 210 and the second protection device 220 include an alarm signal, a lockout signal, a DC power supply loss of voltage signal and a protection channel abnormal signal. Specifically, the alarm signal is a signal indicating that the protection device (i.e., the first protection device 210 or the second protection device 220, the same below) issues an alarm, the lockout signal is a signal indicating that the protection device is locked out, the DC power supply loss of voltage signal is a signal corresponding to the loss of voltage of the DC power supply of the protection device, and the protection channel abnormal signal is a signal indicating that the protection channel of the protection device is in an abnormal state.

[0060] In an embodiment, the measurement and control device 30 is configured to determine that the breakers on both sides of the branch 10 are allowed to be closed manually or remotely when the first preset condition is met. Accordingly, the first preset condition specifically includes that the secondary side of the three-phase voltage transformer PT has voltage, the live display M detects that the three phases of the branch 10 all have voltage, the first main switch, the second main switch, the first branch switch, the second branch switch and the third branch switch are all in the closed position, the first protection device 210 and the second protection device 220 do not issue the alarm signal, the lockout signal, the DC power supply loss of voltage signal and the protection channel abnormal signal.

[0061] Next, taking the protection circuit of the 500 kV line branch 10a as an example, a case of allowing the breakers D1 and D2 on both sides of the 500 kV line branch 10a to be closed is described.

[0062] In combination with Figure 1 and Figure 2The measurement and control device 30 can monitor the voltage of the secondary side of the three-phase voltage transformer PT1 by detecting the voltages of the first node N1, the second node N2 and the third node N3, or collect the signals of the first voltage monitoring relay YJS2 and the second voltage monitoring relay YJS3, and determine whether the secondary side of the three-phase voltage transformer PT1 has voltage. The live display M can monitor the three-phase voltage of the 500 kV line branch 10a, and the live display M includes an auxiliary contact indicating that the three phases of the 500 kV line branch 10a all have voltage, which can be connected to the measurement and control device 30 to enable the measurement and control device 30 to determine whether the three phases of the 500 kV line branch 10a all have voltage. The first main switch 2CBa to 2CBc, the second main switch 3CBa to 3CBc, the first branch switch ZKK1a to ZKK1c, the second branch switch ZKK2a to ZKK2c and the third branch switch ZKK3a to ZKK3c can each include an auxiliary contact indicating that the corresponding switch is in the closed position and the open position, and each auxiliary contact is connected to the measurement and control device 30 to enable the measurement and control device 30 to determine the open / closed position of the corresponding switch according to the auxiliary contact. The first protection device 210 and the second protection device 220 each include an auxiliary contact indicating whether an alarm signal, a blocking signal, a DC power supply voltage loss signal and a protection channel abnormal signal are sent, and the auxiliary contact can be connected to the measurement and control device 30 to enable the measurement and control device 30 to determine whether the first protection device 210 and the second protection device 220 send the above signals.

[0063] When the measurement and control device 30 detects that the secondary side of the three-phase voltage transformer PT1 all has voltage, the live display M detects that the three phases of the 500 kV line branch 10a all have voltage, the first main switch 2CBa to 2CBc, the second main switch 3CBa to 3CBc, the first branch switch ZKK1a to ZKK1c, the second branch switch ZKK2a to ZKK2c and the third branch switch ZKK3a to ZKK3c are all in the closed position, and the first protection device 210 and the second protection device 220 do not send an alarm signal, a blocking signal, a DC power supply voltage loss signal and a protection channel abnormal signal, it is determined that the first preset condition is currently met, and the breakers D1 and D2 on both sides of the 500 kV line branch 10a are allowed to be closed to avoid false operation of the first protection device 210 and the second protection device 220.

[0064] In another embodiment, the first preset condition includes that the secondary side of the three-phase voltage transformer PT has no voltage, the live display M detects that the three phases of the branch 10 all have no voltage, the first main switch, the second main switch, the first branch switch, the second branch switch and the third branch switch are all in the closed position, and the first protection device 210 and the second protection device 220 do not send an alarm signal, a blocking signal, a DC power supply voltage loss signal and a protection channel abnormal signal.

[0065] The following still takes the protection circuit of the 500 kV line branch 10a as an example to illustrate another case of allowing the closing of the circuit breakers D1 and D2 on both sides of the 500 kV line branch 10a.

[0066] Specifically, the measurement and control device 30 determines that the first preset condition is met when it is detected that there is no voltage on the secondary side of the three-phase voltage transformer PT1, the live display M detects that there is no voltage on the three phases of the 500 kV line branch 10a, the first general switch 2CBa to 2CBc, the second general switch 3CBa to 3CBc, the first branch switch ZKK1a to ZKK1c, the second branch switch ZKK2a to ZKK2c and the third branch switch ZKK3a to ZKK3c are all in the closed position, the first protection device 210 and the second protection device 220 do not send alarm signals, blocking signals, DC power supply voltage loss signals and protection channel abnormal signals, and allows the closing of the circuit breakers D1 and D2 on both sides of the 500 kV line branch 10a to avoid false operation of the first protection device 210 and the second protection device 220.

[0067] It should be noted that the measurement and control device 30 can determine to allow the manual or remote closing of the circuit breakers on both sides of the branch 10 when it is simultaneously satisfied that there is voltage on the secondary side of the three-phase voltage transformer PT, the live display M detects that there is voltage on the three phases of the branch 10, the first general switch, the second general switch, the first branch switch, the second branch switch and the third branch switch are all in the closed position, the first protection device 210 and the second protection device 220 do not send alarm signals, blocking signals, DC power supply voltage loss signals and protection channel abnormal signals, or simultaneously satisfied that there is no voltage on the secondary side of the three-phase voltage transformer PT, the live display M detects that there is no voltage on the three phases of the branch 10, the first general switch, the second general switch, the first branch switch, the second branch switch and the third branch switch are all in the closed position, the first protection device 210 and the second protection device 220 do not send alarm signals, blocking signals, DC power supply voltage loss signals and protection channel abnormal signals.

[0068] In combination with Figure 1 and Figure 2 On the basis of the above-mentioned embodiments, disconnecting switches are connected at both ends of each circuit breaker, the disconnecting switches connected to different circuit breakers are different, and the branch 10 is connected between the two disconnecting switches connected to adjacent two circuit breakers. The measurement and control device 30 is further used to determine to allow the manual or remote closing of the circuit breaker on one side of the branch 10 when the second preset condition is met, and the second preset condition includes that the disconnecting switches connected at both ends of the circuit breaker are all in the open position, the motor power supplies of the disconnecting switches connected at both ends of the circuit breaker are all disconnected, the motor power supplies of the disconnecting switches connected at both ends of the circuit breaker are all equipped with five-prevention isolation locks, and the circuit breaker is in a maintenance state.

[0069] Exemplarily, the two ends of the circuit breaker D1 are connected with the disconnector K11 and the disconnector K12 respectively, the two ends of the circuit breaker D2 are connected with the disconnector K21 and the disconnector K22 respectively, and the two ends of the circuit breaker D3 are connected with the disconnector K31 and the disconnector K32 respectively. The 500 kV line branch 10a is specifically connected between the disconnector K12 and the disconnector K21, and the 500 kV transformer branch 10b is specifically connected between the disconnector K22 and the disconnector K31. The line section where the circuit breaker D1, the disconnector K11 and the disconnector K12 are located can be recorded as the line L1, the line section where the circuit breaker D2, the disconnector K21 and the disconnector K22 are located can be recorded as the line L2, and the line section where the circuit breaker D3, the disconnector K31 and the disconnector K32 are located can be recorded as the line L3. The measurement and control device 30 in the protection circuit of the 500 kV line branch 10a can be used to determine that the circuit breaker D1 in the line L1 and / or the circuit breaker D2 in the line L2 are allowed to be closed when the second preset condition is met. The measurement and control device 30 in the protection circuit of the 500 kV transformer branch 10b can be used to determine that the circuit breaker D2 in the line L2 and / or the circuit breaker D3 in the line L3 are allowed to be closed when the second preset condition is met.

[0070] The following still takes the protection circuit of the 500 kV line branch 10a as an example for description:

[0071] For the line L1, the disconnectors K11 and K12 can each include an auxiliary contact indicating the respective on and off states, each of which is connected to the control device 30 to enable the control device 30 to determine the on / off state of the corresponding switch according to the auxiliary contact. The line L1 further includes auxiliary contacts of the motor power supply of the disconnectors K11 and K12 in the on / off state, each of which is connected to the control device 30 to enable the control device 30 to determine the motor power supply state of the disconnectors K11 and K12 according to the auxiliary contact. The line L1 further includes auxiliary contacts of whether the motor power supply of the disconnectors K11 and K12 is equipped with a five-protection isolation lock, each of which is connected to the control device 30 to enable the control device 30 to determine whether the motor power supply of the disconnectors K11 and K12 is equipped with a five-protection isolation lock according to the auxiliary contact. The circuit breaker D1 further includes an auxiliary contact indicating whether it is in a maintenance state, which is connected to the control device 30 to enable the control device 30 to determine whether the circuit breaker D1 is in a maintenance state according to the auxiliary contact. When the control device 30 detects that the disconnectors K11 and K12 are both in the off state, the motor power supply of the disconnectors K11 and K12 is both off, the motor power supply of the disconnectors K11 and K12 is both equipped with a five-protection isolation lock, and the circuit breaker D1 is in a maintenance state, it is determined that the second preset condition is currently met, and there is no need to determine whether the first preset condition is currently met, and the circuit breaker D1 is directly allowed to be closed.

[0072] Similarly, for the line L2, the disconnectors K21 and K22 can each include an auxiliary contact indicating the respective on and off states, each of which is connected to the control device 30, so that the control device 30 can determine the on / off state of the corresponding switch according to each auxiliary contact. The line L2 also includes auxiliary contacts of the motor power supply of the disconnectors K21 and K22 in the on / off state, each of which is connected to the control device 30, so that the control device 30 can determine the motor power supply state of the disconnectors K21 and K22 according to each auxiliary contact. The line L2 also includes auxiliary contacts of the disconnectors K21 and K22 to determine whether the motor power supply is equipped with a five-protection isolation lock, each of which is connected to the control device 30, so that the control device 30 can determine whether the motor power supply of the disconnectors K21 and K22 is equipped with a five-protection isolation lock according to each auxiliary contact. The circuit breaker D2 also includes an auxiliary contact indicating whether it is in a maintenance state, which is connected to the control device 30, so that the control device 30 can determine whether the circuit breaker D2 is in a maintenance state according to the auxiliary contact. When the control device 30 detects that the disconnectors K21 and K22 are both in the off state, the motor power supply of the disconnectors K21 and K22 is both disconnected, the motor power supply of the disconnectors K21 and K22 is both equipped with a five-protection isolation lock, and the circuit breaker D2 is in a maintenance state, it is determined that the second preset condition is currently met, and there is no need to determine whether the first preset condition is currently met, and the circuit breaker D2 is directly allowed to be closed.

[0073] The protection circuit of the 500kV transformer branch 10b is similar to the working principle of the protection circuit of the 500kV line branch 10a, and the specific way of determining whether to allow the circuit breakers D2 and D3 on both sides of the 500kV transformer branch 10b to be closed according to the first preset condition, and the specific way of determining whether to allow the circuit breakers D2 and D3 to be closed according to the second preset condition can be understood with reference to the above embodiments, and will not be repeated.

[0074] Figure 3 is a structural schematic diagram of a control device provided by an embodiment of the application. In combination with Figures 1 to 3On the basis of the above embodiments, the measurement and control device 30 comprises a device state acquisition module 310, an analog quantity acquisition module 320, a power conversion module 330 and a control module 340. The device state acquisition module 310 is used to acquire the on / off state signals of the corresponding circuit breaker and disconnector, the preset abnormal state signals of the first protection device 210 and the second protection device 220, the voltage signals of the first node N1, the second node N2 and the third node N3, the on / off state signals of the first total switch, the second total switch, the first branch switch, the second branch switch and the third branch switch, the motor power state signal of the disconnector and the maintenance state signals of the first protection device 210 and the second protection device 220. The analog quantity acquisition module 320 is used to acquire the single-phase voltage signal F1 of the first bus 1M and the bus, the three-phase voltage signal F2, the three-phase current signal F3 and the zero sequence current signal F4 of the branch 10. The power conversion module 330 is used to convert the input power signal V to supply power to the measurement and control device 30. The control module 340 is connected to the device state acquisition module 310, the analog quantity acquisition module 320, the power conversion module 330, the corresponding circuit breaker and disconnector, and is used to control the corresponding circuit breaker and disconnector.

[0075] In particular, the device state acquisition module 310 can be connected to the auxiliary contacts described in the above embodiments to acquire the responsive device state signals through the auxiliary contacts. For example, for the protection circuit of the 500 kV line branch 10a, the device state acquisition module 310 can acquire the on / off state signals E1 of the circuit breaker D1, the on / off state signals E2 of the disconnector K11, the on / off state signals E3 of the disconnector K12, the on / off state signals E4 of the circuit breaker D2, the on / off state signals E5 of the disconnector K21, the on / off state signals E6 of the disconnector K22, the preset abnormal state signals (including the alarm signal, the blocking signal, the DC power supply voltage loss signal and the protection channel abnormal signal) E7 of the first protection device 210, the line side voltage abnormal signal E8 of the first protection device 210, the on / off state signals E9 of the first disconnector ZKK1a to ZKK1c, the preset abnormal state signals (including the alarm signal, the blocking signal, the DC power supply voltage loss signal and the protection channel abnormal signal) E10 of the second protection device 220, the line side voltage abnormal signal E11 of the second protection device 220, the on / off state signals E12 of the second disconnector ZKK2a to ZKK2c, the voltage abnormal signal E13 of the 500 kV line branch 10a, the on / off state signals E14 of the first total switch 2CBa to 2CBc, the on / off state signals E15 of the second total switch 3CBa to 3CBc, the voltage signal E16 detected by the live display M, the motor power supply state signal E17 of the disconnector K11, the motor power supply state signal E18 of the disconnector K12, the motor power supply state signal E19 of the disconnector K21, the motor power supply state signal E20 of the disconnector K22, the maintenance state signal E21 of the first protection device 210 and the maintenance state signal E22 of the second protection device 220, and the like. The control module 340 can perform blocking logic judgment according to the state signals of various devices acquired by the device state acquisition module 310 and the analog signals collected by the analog quantity acquisition module 320 to control each disconnector and circuit breaker in the lines L1 and L2 on both sides of the 500 kV line branch 10a.

[0076] Further, the protection system of the substation further comprises a microcomputer five-prevention system, a monitoring system, an intelligent operation and maintenance system, and a dispatching automation system. The measurement and control device 30 further comprises a first intra-station interconnection interface 351, a second intra-station interconnection interface 352, a third intra-station interconnection interface 353, a fourth intra-station interconnection interface 354, a fifth intra-station interconnection interface 355, and a synchronous time synchronization interface 360. The control module 340 can exchange information with the station control layer A network through the first intra-station interconnection interface 351 to transmit information to the monitoring system and the dispatching automation system, exchange information with the station control layer B network through the second intra-station interconnection interface 352 to transmit information to the monitoring system and the dispatching automation system, exchange information with the station control layer C network through the second intra-station interconnection interface 353 to transmit information to the monitoring system and the dispatching automation system, exchange information with the first process layer network through the fourth intra-station interconnection interface 354, exchange information with the second process layer network through the fifth intra-station interconnection interface 355, and receive a synchronous time synchronization signal through the synchronous time synchronization interface 360.

[0077] The control module 340 is further connected to a first lock-to-close contact 361, a second lock-to-close contact 362, a third lock-to-close contact 363, a fourth lock-to-close contact 364, a fifth lock-to-close contact 365, and a sixth lock-to-close contact 366. The first lock-to-close contact 361 is a contact of the lock-to-close circuit breaker D1, which cannot be closed after being disconnected, and an empty contact can be connected in series to the closing loop of the circuit breaker D1. The second lock-to-close contact 362 is a contact of the lock-to-close circuit breaker D2, which cannot be closed after being disconnected, and an empty contact can be connected in series to the closing loop of the circuit breaker D2. The third lock-to-close contact 363 is a contact of the lock-to-close disconnector K11, which cannot be closed after being disconnected, and an empty contact can be connected in series to the closing loop of the disconnector K11. The fourth lock-to-close contact 364 is a contact of the lock-to-close disconnector K12, which cannot be closed after being disconnected, and an empty contact can be connected in series to the closing loop of the disconnector K12. The fifth lock-to-close contact 365 is a contact of the lock-to-close disconnector K21, which cannot be closed after being disconnected, and an empty contact can be connected in series to the closing loop of the disconnector K21. The sixth lock-to-close contact 366 is a contact of the lock-to-close disconnector K22, which cannot be closed after being disconnected, and an empty contact can be connected in series to the closing loop of the disconnector K22.

[0078] In the above embodiments, according to the first preset condition and the second preset condition, the lock-to-close logic judgment of whether to allow the circuit breakers on both sides of the 500 kV line branch 10a and the 500 kV transformer branch 10b to close can be simultaneously implemented in the measurement and control device 30, the monitoring system, the intelligent operation and maintenance system, and the dispatching automation system, so as to realize operation at multiple positions through the deployment of lock-to-close logic at different positions, and the related state of secondary equipment can participate in the anti-misoperation lock-to-close logic of primary equipment through the lock-to-close logic judgment of the present application, so as to fully combine primary and secondary anti-misoperation.

[0079] Optionally, the measurement and control device 30 is configured to receive control instructions of the monitoring system, the intelligent operation and maintenance system, or the dispatching automation system, and execute the control instructions when the control instructions meet the locking requirements, so as to control the corresponding circuit breakers and disconnectors. Alternatively, at least one of the microcomputer five-protection system, the monitoring system, the intelligent operation and maintenance system, and the dispatching automation system is configured to control each circuit breaker and disconnector.

[0080] The following still takes the protection circuit of the 500kV line branch 10a as an example for description:

[0081] (1) Locking logic judgment and corresponding control are performed by the measurement and control device

[0082] Specifically, the measurement and control device 30 can collect the operating state signals of each primary device and the operating state signals of each secondary device in the above-mentioned embodiments by the air contact point mode, and communicate with the microcomputer five-protection system in the substation through the network, so as to transmit the operating state signals of the primary device and the operating state signals of the secondary device collected by the measurement and control device 30 to the microcomputer five-protection system, and collect the state signals of whether the five-protection isolation lock is installed for the motor power supply of the disconnector K11, the disconnector K12, the disconnector K21, and the disconnector K22.

[0083] The measurement and control device 30 can sample through the analog quantity sampling module 320 to obtain the single-phase voltage signal F1 of the first bus 1M and the bus, the three-phase voltage signal F2 of the branch 10, the three-phase current signal F3, and the zero-sequence current signal F4, and transmit the above-mentioned signals to the microcomputer five-protection system.

[0084] The measurement and control device 30 can communicate with the monitoring system in the substation through the network, transmit various signals collected by the measurement and control device 30 to the monitoring system, and accept the control instructions including the locking instructions and the opening / closing instructions issued by the monitoring system. After the measurement and control device 30 receives the control instructions issued by the monitoring system, the above-mentioned locking logic judgment is performed, and the control instructions are executed when the locking requirements are met, so as to prevent the control instructions from not being executed. The control instructions not being executed can send the corresponding reasons for not being executed to the monitoring system.

[0085] The measurement and control device 30 can communicate with the intelligent operation and maintenance system in the substation through the network, transmit various signals collected by the measurement and control device 30 to the intelligent operation and maintenance system, and accept the control instructions including the locking instructions and the opening / closing instructions issued by the intelligent operation and maintenance system. After the measurement and control device 30 receives the control instructions issued by the intelligent operation and maintenance system, the above-mentioned locking logic judgment is performed, and the control instructions are executed when the locking requirements are met, so as to prevent the control instructions from not being executed. The control instructions not being executed can send the corresponding reasons for not being executed to the intelligent operation and maintenance system.

[0086] The measurement and control device 30 can communicate with the dispatch automation system in the substation through the network, transmit various signals collected by the measurement and control device 30 to the dispatch automation system, and accept the control instructions issued by the dispatch automation system, including the locking instructions and the closing / opening instructions. After the measurement and control device 30 receives the control instructions issued by the dispatch automation system, the above locking logic judgment will be performed, and if the non-locking requirement is met, the control instruction will be executed to prevent non-execution. The control instruction that is not executed can send the reason for non-execution to the dispatch automation system.

[0087] It can be seen that in the case of executing the control instructions of the monitoring system, the intelligent operation and maintenance system or the dispatch automation system through the measurement and control device, the measurement and control device can perform locking logic judgment on the received control instructions again to improve the reliability of system operation.

[0088] (2) Locking logic judgment and corresponding control through the microcomputer five-prevention system

[0089] Specifically, the measurement and control device 30 and the microcomputer five-prevention system in the substation can be used to collect various signals in the substation completely, and the microcomputer five-prevention system can be used to collect the state signals of whether the five-prevention isolation lock is installed on the motor power supply of the disconnecting switch K11, the disconnecting switch K12, the disconnecting switch K21 and the disconnecting switch K22, and the above locking logic judgment and corresponding control can be performed through the microcomputer five-prevention system to realize the operation and locking of the primary equipment. When the microcomputer five-prevention system performs the above locking logic judgment and corresponding control, double locking can be realized through the cooperation of the locking contact of the measurement and control device 30, thereby improving the reliability of system operation.

[0090] (3) Locking logic judgment and corresponding control through the monitoring system

[0091] Specifically, the measurement and control device 30 and the monitoring system in the substation can be used to collect various signals in the substation completely, and the microcomputer five-prevention system can be used to collect the state signals of whether the five-prevention isolation lock is installed on the motor power supply of the disconnecting switch K11, the disconnecting switch K12, the disconnecting switch K21 and the disconnecting switch K22, and the above locking logic judgment and corresponding control can be performed through the monitoring system to realize the operation and locking of the primary equipment.

[0092] (4) Locking logic judgment and corresponding control through the intelligent operation and maintenance system

[0093] Specifically, the complete collection of various signals in the substation can be performed by the measurement and control device 30 and the intelligent operation and maintenance system in the substation, and the state signals of whether the motor power of the disconnecting switch K11, the disconnecting switch K12, the disconnecting switch K21 and the disconnecting switch K22 are equipped with the five-prevention isolation lock are collected by the microcomputer five-prevention system, and the foregoing locking logic judgment is performed by the intelligent operation and maintenance system, and corresponding control is performed to realize the operation and locking of the primary equipment.

[0094] (5) Locking logic judgment and corresponding control are performed by the dispatching automation system

[0095] Specifically, the complete collection of various signals in the substation can be performed by the measurement and control device 30 and the dispatching automation system in the substation, and the state signals of whether the motor power of the disconnecting switch K11, the disconnecting switch K12, the disconnecting switch K21 and the disconnecting switch K22 are equipped with the five-prevention isolation lock are collected by the microcomputer five-prevention system, and the foregoing locking logic judgment is performed by the dispatching automation system, and corresponding control is performed to realize the operation and locking of the primary equipment.

[0096] The foregoing embodiments only take the protection circuit of the 500kV line branch 10a as an example to describe the principle of the specific structure of the measurement and control device and the locking logic judgment and corresponding control of the protection circuit, and the specific structure of the measurement and control device of the protection circuit of the 500kV transformer branch 10b and the principle of the locking logic judgment and corresponding control of the protection circuit are similar to those of the foregoing embodiments, and can be understood with reference to the foregoing content, which will not be described herein again.

[0097] Figure 4 is a structure schematic diagram of a protection system of a substation provided by an embodiment of the present application. In combination with the foregoing description of the measurement and control device of the protection system of the substation, the principle of the locking logic judgment and corresponding control of the protection circuit of the substation is described in detail. Figures 1 to 4On the basis of the above embodiments, the protection system of the substation can include the first measuring and control device 510, the second measuring and control device 520, the third measuring and control device 530, the fourth measuring and control device 540, the fifth measuring and control device 550, and the sixth measuring and control device 560. The first measuring and control device 510 can be a measuring and control device of a first bus voltage transformer, for example, a measuring and control device of the voltage transformer PT3 connected to the first bus 1M. The second measuring and control device 520 can be a measuring and control device of a second bus voltage transformer, for example, a measuring and control device of the voltage transformer PT4 connected to the second bus 2M. The third measuring and control device 530 can be a measuring and control device 30 in the protection circuit of the 500kV line branch 10a. The fourth measuring and control device 540 can be a measuring and control device 30 in the protection circuit of the 500kV transformer branch 10b. The fifth measuring and control device 550 can be a measuring and control device of a related bus and section in the substation, and the sixth measuring and control device 560 can be other related measuring and control devices in the substation. The monitoring system host 570, the microcomputer five-protection system host 580, the intelligent operation and maintenance system host 590, the dispatching intelligent operation and maintenance system host 620, and the dispatching automation system host 630 can communicate through the communication network 610. When the monitoring system host 570, the microcomputer five-protection system host 580, and the intelligent operation and maintenance system host 590 can be located inside the substation 50, the first measuring and control device 510 to the sixth measuring and control device 560 can communicate with the monitoring system host 570, the microcomputer five-protection system host 580, and the intelligent operation and maintenance system host 590 through the station control layer network.

[0098] The embodiment of the present application also provides a protection method of a substation, which is executed by the protection system of the substation in any of the above embodiments. The protection method of the substation specifically includes:

[0099] The measuring and control device judges whether to control the breakers on both sides of the branch to close according to the first preset condition, and the first preset condition includes whether there is voltage at the secondary side of the three-phase voltage transformer, whether the first general switch, the second general switch, the first branch switch, the second branch switch, and the third branch switch are in the closed position, and whether the first protection device and the second protection device send a preset abnormal state signal.

[0100] It should be understood that the various forms of flow shown above can be reordered, added, or deleted steps. For example, each step described in the present application can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions of the present application can be achieved, which is not limited herein.

[0101] The above detailed description does not limit the scope of the application. Various modifications, combinations, sub-combinations and alternatives can be made to the detailed description. Any modification, equivalent replacement and improvement etc. made within the spirit and principle of the application shall be included in the scope of the application.

Claims

1. A protection system for a substation, characterized in that, The substation includes a first busbar, a second busbar, and three circuit breakers connected in series between the first busbar and the second busbar. A branch line is connected between two adjacent circuit breakers, and the branch line includes a line branch line or a main transformer branch line. The protection system of the substation includes: a protection circuit corresponding to each of the branches, the protection circuit including: A three-phase voltage transformer, connected to the corresponding branch, includes a first secondary winding and a second secondary winding, both of which include three-phase windings; The first protection device, the first main switch and the first branch switch, wherein each phase winding of the first secondary winding is connected to one phase input terminal of the first protection device in sequence through a first main switch and a first branch switch; The second protection device, the second main switch, and the second branch switch; each phase winding of the second secondary winding is connected to one phase input terminal of the second protection device in sequence through a second main switch and a second branch switch. The measurement and control device and the third branch switch are provided. The A-phase input terminal of the measurement and control device is connected to the first node through the third branch switch. The first node is located between the first main switch and the first branch switch corresponding to the A-phase winding of the first secondary winding. The B-phase input terminal of the measurement and control device is connected to the second node through the third branch switch. The second node is located between the first main switch and the first branch switch corresponding to the B-phase winding of the first secondary winding. The C-phase input terminal of the measurement and control device is connected to the third node through the third branch switch. The third node is located between the first main switch and the first branch switch corresponding to the C-phase winding of the first secondary winding. The measurement and control device is used to determine whether to control the circuit breakers on both sides of the branch to close based on a first preset condition. The first preset condition includes: whether there is voltage on the secondary side of the three-phase voltage transformer, whether the first main switch, the second main switch, the first branch switch, the second branch switch and the third branch switch are in the closed position, and whether the first protection device and the second protection device issue a preset abnormal status signal. The protection circuit also includes: A live display, connected to the corresponding branch, is used to detect and display the three-phase voltage of the branch; The first voltage monitoring relay is connected between the first main switch and the first node corresponding to the A phase winding of the first secondary winding, between the first main switch and the second node corresponding to the B phase winding of the first secondary winding, and between the first main switch and the third node corresponding to the C phase winding of the first secondary winding. The second voltage monitoring relay is connected between the second main switch and the second branch switch corresponding to the A phase winding of the second secondary winding, between the second main switch and the second branch switch corresponding to the B phase winding of the second secondary winding, and between the second main switch and the second branch switch corresponding to the C phase winding of the second secondary winding. The first preset condition further includes: whether the live display detects that all three phases of the branch have voltage; the measurement and control device is also used to detect the voltage of the first node, the second node and the third node to determine whether there is voltage on the secondary side of the three-phase voltage transformer, or to determine whether there is voltage on the secondary side of the three-phase voltage transformer based on the signals of the first voltage monitoring relay and the second voltage monitoring relay.

2. The substation protection system according to claim 1, characterized in that, The preset abnormal status signals include: alarm signals, lockout signals, DC power supply undervoltage signals, and protection channel abnormal signals.

3. The substation protection system according to claim 1, characterized in that, The monitoring and control device is used to determine whether the circuit breakers on both sides of the branch can be manually or remotely closed when the first preset condition is met. The first preset conditions specifically include: there is voltage on the secondary side of the three-phase voltage transformer; the live display detects that all three phases of the branch have voltage; the first main switch, the second main switch, the first branch switch, the second branch switch, and the third branch switch are all in the closed position; and neither the first protection device nor the second protection device issues an alarm signal, a lockout signal, a DC power supply undervoltage signal, or a protection channel abnormality signal.

4. The substation protection system according to claim 1, characterized in that, The first preset conditions specifically include: no voltage on the secondary side of the three-phase voltage transformer; the live display detects no voltage on all three phases of the branch; the first main switch, the second main switch, the first branch switch, the second branch switch, and the third branch switch are all in the closed position; and neither the first protection device nor the second protection device issues an alarm signal, a lockout signal, a DC power supply undervoltage signal, or a protection channel abnormality signal.

5. The substation protection system according to claim 1, characterized in that, Each circuit breaker is connected to two disconnect switches at both ends. Different circuit breakers are connected to different disconnect switches. The branch is connected between the two disconnect switches connected to two adjacent circuit breakers. The monitoring and control device is also used to determine whether the circuit breaker on one side of the branch can be manually or remotely closed when a second preset condition is met, the second preset condition including: The disconnecting switches connected to both ends of the circuit breaker are all in the open position, the motor power supply of the disconnecting switches connected to both ends of the circuit breaker is disconnected, the motor power supply of the disconnecting switches connected to both ends of the circuit breaker is equipped with a five-proof isolation lock, and the circuit breaker is in maintenance status.

6. The protection system for a substation according to any one of claims 1-5, characterized in that, The measurement and control device includes: The equipment status acquisition module is used to acquire the open / closed position status signals of the corresponding circuit breakers and disconnectors, the preset abnormal status signals of the first protection device and the second protection device, the voltage signals of the first node, the second node and the third node, the open / closed position status signals of the first main switch, the second main switch, the first branch switch, the second branch switch and the third branch switch, the motor power supply status signal of the disconnector, and the maintenance status signals of the first protection device and the second protection device. The analog quantity acquisition module is used to acquire the single-phase voltage of the first bus and the bus, the three-phase voltage, three-phase current and zero-sequence current of the branch; A power conversion module is used to convert the input power to supply power to the measurement and control device; The control module is connected to the device status acquisition module, the analog quantity acquisition module, the power conversion module, the corresponding circuit breaker and the disconnect switch, and is used to control the corresponding circuit breaker and disconnect switch.

7. The substation protection system according to claim 6, characterized in that, The substation's protection system also includes: a microcomputer-based five-prevention system, a monitoring system, an intelligent operation and maintenance system, and a dispatch automation system; the measurement and control device communicates with the microcomputer-based five-prevention system, the monitoring system, the intelligent operation and maintenance system, and the dispatch automation system through the control module; The monitoring and control device is also used to receive control commands from the monitoring system, the intelligent operation and maintenance system, or the dispatch automation system, and execute the control commands when the control commands meet the interlocking requirements, so as to control the corresponding circuit breaker and the disconnecting switch.

8. The substation protection system according to claim 7, characterized in that, At least one of the microcomputer-based five-prevention system, the monitoring system, the intelligent operation and maintenance system, and the dispatch automation system is also used to control each of the circuit breakers and the disconnect switches.

9. A protection method for a substation, characterized in that, Performed by the protection system of the substation as described in any one of claims 1-8; The substation includes a first busbar, a second busbar, and three circuit breakers connected in series between the first busbar and the second busbar. A branch line is connected between two adjacent circuit breakers, and the branch line includes a line branch line or a main transformer branch line. The protection system of the substation includes: a protection circuit corresponding to each of the branches, the protection circuit including: A three-phase voltage transformer, connected to the corresponding branch, includes a first secondary winding and a second secondary winding, both of which include three-phase windings; The first protection device, the first main switch and the first branch switch, wherein each phase winding of the first secondary winding is connected to one phase input terminal of the first protection device in sequence through a first main switch and a first branch switch; The second protection device, the second main switch, and the second branch switch; each phase winding of the second secondary winding is connected to one phase input terminal of the second protection device in sequence through a second main switch and a second branch switch. The measurement and control device and the third branch switch are provided. The A-phase input terminal of the measurement and control device is connected to the first node through the third branch switch. The first node is located between the first main switch and the first branch switch corresponding to the A-phase winding of the first secondary winding. The B-phase input terminal of the measurement and control device is connected to the second node through the third branch switch. The second node is located between the first main switch and the first branch switch corresponding to the B-phase winding of the first secondary winding. The C-phase input terminal of the measurement and control device is connected to the third node through the third branch switch. The third node is located between the first main switch and the first branch switch corresponding to the C-phase winding of the first secondary winding. The protection methods for the substation include: The measurement and control device determines whether to close the circuit breakers on both sides of the branch according to the first preset conditions. The first preset conditions include: whether there is voltage on the secondary side of the three-phase voltage transformer, whether the first main switch, the second main switch, the first branch switch, the second branch switch and the third branch switch are in the closed position, and whether the first protection device and the second protection device issue preset abnormal status signals.

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