CN104037934A - Spare power automatic switching emergency device and method for power utilization system of transformer substation - Google Patents

Abstract

The invention provides a self-switching emergency device for substation power system, including a sampling unit, a protection unit, a switching transistor and a logic control unit; the local switch in the sampling unit is connected to the incoming power line and the busbar of the local side, and the bus tie switch Connect to the opposite side bus, the voltage sampling module is connected to the opposite side power supply line, the current sampling module is connected to the local bus; the protection unit is connected to the sampling unit, which is used to determine the working mode according to the current value of the local bus and send it to the switching transistor Level signal; the switching transistor is connected to the above three units respectively, and is used to turn on or off according to the level signal; the logic control unit is used when the switching transistor is turned on, according to the three-phase voltage of the incoming power line of the opposite side The value is used to determine whether to enable the incoming power line of the local side or the opposite busbar to supply power to the busbar of the local side. The implementation of the present invention has the advantages of simple structure, quick disassembly, avoiding the risk of long-term pressure loss of the local busbar, and saving a lot of financial resources and time.

Description

A device and method for automatic switch-on emergency of substation power consumption system

technical field

The invention relates to the technical field of power system substation power consumption systems in electric power systems, and in particular to a device and method for automatic switch-on emergency of substation power system power consumption systems.

Background technique

As shown in Figure 1, the power system of the substation station provides a stable and reliable 380V AC power supply for the AC load in the substation. The AC power supply of the section bus b' is respectively drawn from the low-voltage side of two station transformers which are mutually standby, that is, the section I bus a' is transformed from a 10KV AC power supply to # Station #1 of power supply P1 for station 1 supplies power, and busbar b' of section II is transformed from 10KV AC power supply to station #2 of power supply P2 for station #2 through ST2 of the station transformer and other transformer devices. Line powered. When the busbar a' of section I loses the incoming power supply of the #1 station with the power supply P1, that is, the incoming switch 1QF of the #1 station fails to open, then the backup self-injection device installed in the bus AC incoming line panel M1 in the #1 station By closing the bus tie switch 3QF, N1 switches to the bus b' of section II which is powered by the power supply P2 of station #2, so as to avoid the voltage loss of bus a' of section I; when the bus b' of section II loses the power supply P2 of station #2 When the line is powered, that is, the incoming line switch 2QF of station #2 fails and disconnects, the backup self-injection device N2 installed in the bus AC incoming line panel M2 in station #2 will switch to the station #1 by closing the bus tie switch 3QF The power supply P1 enters the I-section bus a' for power supply to avoid voltage loss of the II-section bus b'.

At present, the self-switching devices of substation station power system are widely used in various substations of the power system. The device involves too many manufacturers and the product types are too complicated. The disadvantages are: 1. Due to too many manufacturers, once If the device fails, it needs to be returned to different manufacturers for replacement, which wastes a lot of time. In particular, some types of devices have been discontinued, and the waiting time for upgrading is too long, which increases the risk of busbar voltage loss in the station power system; 2. The product type is too complicated. It is not conducive to maintenance, and at the same time, in order to ensure that device failures can be quickly resolved, it is necessary to reserve a large number of spare devices of various product types, thereby wasting a lot of financial resources.

Contents of the invention

The technical problem to be solved by the embodiments of the present invention is to provide a device and method for emergency emergency switching of substation power system, which can be used to replace traditional standby automatic switching devices in emergencies. Its structure is simple, easy to maintain, and avoids The risk of long-term voltage loss of the bus in the side station saves a lot of money and time, and provides a guarantee for the safe and stable operation of the station power system.

In order to solve the above-mentioned technical problems, the embodiment of the present invention provides a device for automatic emergency switching of the substation power system, including a sampling unit, a protection unit, a switching transistor and a logic control unit; wherein,

One end of the sampling unit is connected to one end of the protection unit, and the other end is connected to the source of the switching transistor, which includes a local switch, a bus tie switch, a voltage sampling module and a current sampling module; wherein, the local The two ends of the side switch are respectively connected to the incoming power line of the station on this side and the busbar in the station on this side; one end of the bus tie switch is connected to the busbar in the station on the opposite side, and the other end is connected to the busbar in the station on the same side; the voltage sampling The two ends of the module are respectively connected to the incoming power line for the local station and the incoming power line for the opposite station, and are used to collect the three-phase voltages of the incoming power line for the local station and the incoming power line for the opposite station in real time value; the current sampling module is connected to the bus in the station on the local side, and is used to collect the three-phase current value of the bus in the station on the local side in real time;

The other end of the protection unit is connected to the gate of the switching transistor, and is used to determine the current working mode according to the three-phase current value of the bus in the local station collected in real time, and according to the determined The current working mode sends a corresponding level signal to the switching transistor; wherein, the current working mode includes a protection mode and a normal mode, the level signal corresponding to the protection mode is a low level signal, and the normal mode corresponds to The level signal is a high level signal;

The drain of the switch transistor is connected to the logic control unit, and is used to realize the conduction or disconnection between the sampling unit and the logic control unit according to the level signal sent by the protection unit;

The logic control unit is configured to determine, according to the real-time collected three-phase voltage values of the incoming power lines for the local station and the incoming power lines for the opposite station, when the sampling unit is connected. Enabling the incoming power line for the local station or the opposite station internal bus to supply power to the local internal bus.

Wherein, the logic control unit includes a first voltage relay, a second voltage relay, an intermediate relay and a DC voltage source; wherein, the first voltage relay, the second voltage relay and the intermediate relay are connected in series to form a circuit, and the The circuit formed in series with the phases is connected in parallel with the DC voltage source;

The first voltage relay is used to determine whether it is in an open or closed state according to the magnitude of the three-phase voltage value of the incoming line of the power supply for the local station collected in real time when it is connected to the sampling unit;

The second voltage relay is used to determine whether it is in an open or closed state according to the magnitude of the three-phase voltage value of the incoming power line for the opposite station collected in real time when it is connected to the sampling unit;

The intermediate relay is used to determine whether it is in an open or closed state according to the determined open and close states of the first voltage relay and the second voltage relay when it is connected to the sampling unit, and when connected to the sampling unit When it is turned on, it realizes the control of the on-off state of the switch on the local side and the bus tie switch, so as to determine whether to enable the incoming power line for the station on the local side or the internal busbar on the opposite station to supply power to the internal busbar on the local side.

Wherein, when the sampling unit is turned on, and at least one phase voltage value of the three-phase voltage value of the power supply incoming line of the local station collected in real time is less than a preset voltage threshold and the opposite station When the voltage value of each phase in the three-phase voltage value of the incoming power line is greater than the preset voltage threshold, both the first voltage relay and the second voltage relay are closed, so that the intermediate relay is closed, thereby The circuit connected in series forms a connected circuit. When conducting with the sampling unit, the intermediate relay controls the switch on the local side to be disconnected and the bus tie switch to be closed, so as to determine whether to enable The busbar supplies power to the busbar in the local station.

Wherein, when it is connected to the sampling unit, and each phase voltage value of the three-phase voltage value of the incoming power line of the local station collected in real time is greater than a preset voltage threshold, the first The voltage relay is disconnected, so that the intermediate relay is disconnected, so that the circuit formed in series is in the disconnected state. When conducting with the sampling unit, the intermediate relay controls the closing of the local switch and The bus tie switch is turned off, and it is determined to enable the incoming power line of the local station to supply power to the internal busbar of the local station.

Wherein, the protection mode includes an overcurrent protection mode and a zero-sequence protection mode; wherein,

When any one of the three-phase current values of the bus in the station on the local side collected in real time is greater than the preset first current threshold, the protection unit enters an overcurrent protection mode, controls the switch on the local side to turn off, and sending a low-level signal to the switch transistor, so that the switch transistor is turned off, so as to realize the disconnection between the sampling unit and the logic control unit;

When one-third of the sum of the three-phase current values of the three-phase current values of the bus in the local station collected in real time is greater than the preset second current threshold, the protection unit enters the zero-sequence protection mode and controls the The switch on this side is turned off, and sends a low-level signal to the switch transistor, so that the switch transistor is turned off, realizing disconnection between the sampling unit and the logic control unit.

Wherein, the current sampling module includes three current transformers, and the three current transformers are current transformers based on Rogowski coils, which are respectively connected to the three-phase cables of the busbar in the local station.

Wherein, the voltage sampling module includes six voltage fuses, wherein three voltage fuses are respectively connected to the three-phase incoming lines of the station power supply on this side one by one, and the other three voltage fuses are respectively connected to the The side stations are connected one by one with the three-phase incoming lines of the power supply.

The embodiment of the present invention also provides a method for automatic emergency switching of the substation power system, which is implemented in the aforementioned device for automatic emergency switching of the substation power system. The method includes:

Real-time collection of the three-phase voltage value of the incoming power line for the station on the local side, the three-phase voltage value of the incoming power line for the opposite station, and the three-phase current value of the bus in the station on the local side;

Determine the current working mode according to the three-phase current value of the bus in the local station collected in real time, and send a corresponding level signal according to the determined current working mode; wherein, the current working mode includes protection mode and normal mode, the level signal corresponding to the protection mode is a low level signal, and the level signal corresponding to the normal mode is a high level signal;

receiving the sent level signal, and judging the switching between lines supplying power to the bus in the station on the local side according to the level of the received level signal;

When switching can be realized between the lines supplying power to the bus in the local station, according to the real-time collected three-phase voltage values of the incoming power lines for the local station and the incoming power lines for the opposite station, It is determined to enable the incoming power line for the station on the local side or the internal bus on the opposite side to supply power to the internal bus on the local side.

Wherein, the specific steps of determining the current working mode according to the three-phase current value of the bus in the local station collected in real time, and sending the corresponding level signal according to the determined current working mode include:

When any one of the three-phase current values of the bus in the station on this side collected in real time is greater than the preset first current threshold, determine that the current working mode is the overcurrent protection mode in the protection mode, and send the low Level signal;

When one-third of the sum of the three-phase current values of the three-phase current values of the bus in the station on this side collected in real time is greater than the preset second current threshold, it is determined that the current working mode is the zero-sequence protection mode in the protection mode , and send the low-level signal;

When any current value of the three-phase current values of the bus on the local station collected in real time is less than the preset first current threshold and one-third of the sum of the three-phase current values is less than the preset second When the current threshold is reached, it is determined that the current working mode is the normal mode, and the high level signal is sent.

Wherein, when the switching can be realized between the lines supplying power to the bus in the local station, according to the real-time collected three-phase voltage The specific steps for determining whether to enable the incoming power supply line of the station on this side or the bus on the opposite side to supply power to the bus on the station on this side include:

When at least one phase voltage value of the three-phase voltage values of the incoming power line for the station at the station collected in real time is less than the preset voltage threshold and each of the three-phase voltage values for the incoming power line for the opposite station is When the voltage values of one phase are all greater than the preset voltage threshold, it is determined to enable the internal bus on the opposite side to supply power to the internal bus on the local side;

When the three-phase voltage values of the three-phase voltage values of the local station power supply incoming line collected in real time are greater than the preset voltage threshold, it is determined to enable the local station power supply incoming line to the local station The busbar power supply in the side station.

Implementing the embodiment of the present invention has the following beneficial effects:

1. In the embodiment of the present invention, because the current transformer in the device is based on the Rogowski coil, the net weight is extremely low, the installation is simple and the disassembly is convenient, which overcomes the shortcomings of the traditional current transformer, which is fixed in the installation position and difficult to disassemble.

2. In the embodiment of the present invention, since the device contains a sampling unit, a protection unit and a logic control unit, its structure is simple and easy to maintain, and the sampling unit is completely independent, which is convenient for the operation and maintenance personnel to quickly install and debug, and avoids The risk of long-term voltage loss of the busbar also has the protection functions of zero-sequence protection and over-current protection.

3. In the embodiment of the present invention, since the device can be installed in any substation station power system bus AC incoming line screen, it is used to replace the traditional standby automatic switching device in emergency, which overcomes the waste of resources and turnover caused by the traditional way of storing spare parts Disadvantages of long time.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, obtaining other drawings based on these drawings still belongs to the scope of the present invention without any creative effort.

Fig. 1 is a schematic diagram of the application scene of the backup self-injection device of the 380V main opposite station power system in the prior art;

Fig. 2 is a structural schematic diagram of a device for automatic emergency switching of a power system of a substation station provided by an embodiment of the present invention;

Fig. 3 is a schematic structural diagram of the logic control unit in Fig. 2;

Fig. 4 is a flow chart of a method for automatic emergency switching of a power system of a substation station provided by an embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings.

As shown in Figure 2, the embodiment of the present invention provides a device for self-switching emergency of the power system of the substation station, which is installed in the incoming line panel of any substation station, and realizes the power supply for the station on the local side and the power supply for the station on the opposite side. In order to simplify the description, the following will take the self-switching emergency device installed in the station power system of the local station as an example. In the embodiment of the present invention, the substation station power system is equipped with an emergency device for automatic switching, the device includes a sampling unit 1, a protection unit 2, a switching transistor 3 and a logic control unit 4; wherein,

One end of the sampling unit 1 is connected to one end of the protection unit 2, and the other end is connected to the source S of the switching transistor 3, which includes a local switch K1, a bus tie switch K2, a voltage sampling module 11 and a current sampling module 12; The two ends of the side switch K1 are respectively connected with the power supply line a of the station on this side, and the busbar c in the station at this side; one end of the bus tie switch K2 is connected with the busbar d in the station at the opposite side, and the other end is connected with the busbar c in the station at this side; voltage sampling The two ends of the module 11 are respectively connected to the incoming power line a for the local station and the incoming power line b for the opposite station, and are used to collect the three-phase data of the incoming power line a for the local station and the incoming power line b for the opposite station in real time. Voltage value; the current sampling module 12 is connected with the bus c in the station on this side, and is used to collect the three-phase current value of the bus c in the station on this side in real time;

The other end of the protection unit 2 is connected to the gate G of the switching transistor 3, and is used to determine the current working mode according to the real-time collected three-phase current value of the bus c in the station on this side, and to switch to the switch according to the determined current working mode. The transistor 3 sends a corresponding level signal; wherein, the current working mode includes a protection mode and a normal mode, the level signal corresponding to the protection mode is a low level signal, and the level signal corresponding to the normal mode is a high level signal;

The drain D of the switching transistor 3 is connected to the logic control unit 4, and is used to realize the conduction or disconnection between the sampling unit 1 and the logic control unit 4 according to the level signal sent by the protection unit 2;

The logic control unit 4 is used to determine whether to activate the local side according to the three-phase voltage values of the power supply line a of the station on the own side and the power supply line b of the station on the opposite side collected in real time when it is connected to the sampling unit 1. Incoming power line a for the station or b for the opposite station.

It should be noted that the voltage obtained by transforming the voltage of the power supply line a of the local station or the voltage of the bus d in the opposite station can meet the voltage requirements of the bus c in the local station.

Throughout the device, the voltage sampling module 11 in the sampling unit 1 includes six voltage fuses, among which there are three voltage fuses for real-time acquisition of the three-phase voltage value of the power supply line a of the station at this side. The fuses are respectively connected to the three-phase incoming lines of the station power supply on this side, and there are also three voltage fuses for real-time collection of the three-phase voltage values of the incoming line b of the power supply on the opposite side. The three-phase incoming lines of the station power supply are connected one by one. The structures of these six voltage fuses are the same, and the range of voltage values that can be collected is between 0V and 460V.

The current sampling module 12 in the sampling unit 1 includes three current transformers for real-time collection of the three-phase current values of the bus c in the station on this side. These three current transformers are all current transformers based on Rogowski coils, and are respectively connected The three-phase cables of the busbar c in the station on this side are connected one by one, and the range of current values that can be collected is between 0A and 2500A. Due to the extremely low net weight of each current transformer, simple installation and convenient disassembly, it overcomes the shortcomings of traditional current transformers that are fixed in installation position and difficult to disassemble. Therefore, the sampling unit 1 with independent module and switch design has a simple structure and is easy to operate. The maintenance personnel quickly installed and debugged, avoiding the risk of long-term voltage loss of the bus c of the power consumption system of the local station.

Regardless of whether the local switch K1 of the local station is closed and the bus tie switch K2 is disconnected, a stable and reliable 380V AC power supply is provided to the busbar c in the local station after the transformation of the power supply line a of the local station. When the side switch K1 is turned off and the bus tie switch K2 is closed, a stable and reliable 380V AC power supply is provided to the bus c in the station through the bus d in the opposite station, and the current sampling module 12 in the sampling unit 1 will collect the bus c in the station in real time. The protection unit 2 collects the size of the three-phase current value of the bus c in the station on this side in real time according to the sampling module 12, determines the current working mode, and sends the corresponding level to the switching transistor 3 according to the determined current working mode Signal.

When any one of the three-phase current values of the bus c in the substation on the local side collected in real time is greater than the first current threshold preset in the protection unit 2, the protection unit 2 enters the overcurrent protection mode and controls the switch K1 on the local side to be turned off disconnect, and send a low-level signal to the switching transistor 3, so that the switching transistor 3 is disconnected, and the disconnection between the sampling unit 1 and the logic control unit 4 is realized; When one-third of the sum of the three current values is greater than the second current threshold preset in the protection unit 2, the protection unit 2 enters the zero-sequence protection mode, controls the switch K1 on the local side to turn off, and sends a low-level signal to the switching transistor 3 , so that the switching transistor 3 is disconnected, and the disconnection between the sampling unit 1 and the logic control unit 4 is realized; when the above two protection modes are enabled, the connection between the sampling unit 1 and the logic control unit 4 will be cut off, thereby interrupting the local station Use the power supply line a and the bus d in the station on the opposite side to supply power to the bus c in the station on this side, and block the switching function of the device.

When any of the three-phase current values of the bus c in the local station collected in real time is less than the first current threshold preset in the protection unit 2, and one-third of the sum of the three-phase current values is less than the preset threshold in the protection unit 2 When the second current threshold is set, the protection unit 2 maintains the current normal mode, and sends a high-level signal to the switching transistor 3, so that the switching transistor 3 is closed, and the conduction between the sampling unit 1 and the logic control unit 4 is realized. It should be noted that, when the protection unit 2 returns to the normal mode after enabling the protection mode, no matter whether the power supply line a of the local station is enabled or the busbar d of the opposite station is used to supply power to the internal busbar c of the local station, the internal busbar of the local station c The power supply mode will remain as the power supply mode before the protection unit 2 activates the protection mode.

In order to enable the logic control unit 4 to control the switching state of the local switch K1 and the bus tie switch K2 when it is connected to the sampling unit 1, so that when the power supply line a of the local station fails, it can be switched to the opposite The effect of the busbar d in the side station is shown in Figure 3. A relay protection circuit is used in the device to design the logic control unit 4. The logic control unit 4 includes a first voltage relay J1, a second voltage relay J2, an intermediate relay J3, and a DC voltage source 31; wherein, the first voltage relay J1, the second voltage relay J2, and the intermediate relay J3 are connected in series to form a relay An electrical protection circuit, and the circuit formed in series is connected in parallel with the DC voltage source 31;

The first voltage relay J1 is used to determine whether it is in the disconnected or closed state according to the magnitude of the three-phase voltage value of the incoming power line a of the power station at the station collected in real time when it is connected to the sampling unit 1;

The second voltage relay J2 is used to determine whether it is in the disconnected or closed state according to the magnitude of the three-phase voltage value of the opposite station power supply incoming line b collected in real time when it is connected to the sampling unit 1;

The intermediate relay J3 is used to determine whether it is in the open or closed state according to the determined on-off state of the first relay J1 and the second relay J2 when it is connected to the sampling unit 1, so as to realize the control of the local switch K1 and the bus tie switch K2 The control of the opening and closing state, so as to determine whether to enable the power supply line a of the station on the own side or the busbar d in the station on the opposite side to supply power to the busbar c in the station on the station side.

In the conduction with the sampling unit 1, at least one voltage value of the three-phase voltage values of the power supply line a of the station on the side collected in real time is less than the preset voltage threshold and the three-phase voltage value of the power supply line b of the opposite side station When each of the voltage values is greater than the preset voltage threshold, both the first voltage relay J1 and the second voltage relay J2 are closed, so that the intermediate relay J3 is closed, so that the aforementioned circuits connected in series form a connected circuit, and the intermediate relay J3 controls this The side switch K1 is turned off and the bus-tie switch K2 is closed to confirm that the bus d in the opposite station is activated to supply power to the bus c in the station on the opposite side.

When it is connected to the sampling unit 1, and each of the three-phase voltage values of the station power incoming line a collected in real time is greater than the preset voltage threshold, the first voltage relay J1 is disconnected, so that the intermediate relay J3 is disconnected, so that the above-mentioned series-connected circuit is disconnected, the intermediate relay J3 controls the switch K1 on the local side to close and the bus tie switch K2 to disconnect, and determines to enable the incoming power line a of the station on the local side to the busbar c in the station on the local side powered by.

Furthermore, the DC voltage source 31 includes a 110V DC power supply and a 220V DC power supply. When a 220V DC power supply is used, a voltage converter is needed to convert the 220V DC voltage into a 110V DC voltage.

As an example, install three voltage fuses on the incoming cable of the station power supply on the local side, collect the three-phase voltage values U11, U12, and U13 of the incoming power line a of the station on the local side, and add the three voltage fuses to Installed on the incoming cable of the power supply for the opposite station, collect the three-phase voltage values U21, U22, and U23 of the incoming power line b for the opposite station, and install three current transformers on the 380V bus c in the station at this side, Collect the three-phase current values Ia, Ib, and Ic of the 380V bus c in the station on this side;

When any one of the three-phase current values Ia, Ib, and Ic of the bus c in the local station collected is greater than the built-in overcurrent protection setting (that is, greater than the preset first current threshold), the overcurrent protection is activated. Control the switch K1 on this side to be disconnected, send a low-level signal to the switch transistor 3, so that the switch transistor 3 is disconnected, realize the disconnection between the sampling unit 1 and the logic control unit 4, and the switching function of the blocking device for automatic switching; when the collected One-third of the sum of the three-phase current values Ia, Ib, and Ic of the busbar c is greater than the built-in zero-sequence protection setting value (that is, greater than the preset second current threshold), the zero-sequence protection starts, and the control system The side switch K1 sends a low-level signal to the switching transistor 3, so that the switching transistor 3 is disconnected, and the disconnection between the sampling unit 1 and the logic control unit 4 is realized, and the switching function of the blocking device is self-switching;

When the connection between the sampling unit 1 and the logic control unit 4 is conducted, the device can realize the switching function of standby and automatic switching. If the value is less than the preset voltage threshold (down to 20% of the original voltage value as follows), the first voltage relay J1 is closed, and the collected three-phase voltage values U21, U22, and U23 of the power supply line b of the opposite station are normal. That is, U21, U22, and U23 are all greater than the preset voltage threshold. At this time, the second voltage relay J2 is closed. Since the first voltage relay J1 and the second voltage relay J2 are both closed, the intermediate relay J3 is excited and closed. At this time, the intermediate relay J3 forms a connected circuit with the first voltage relay J1, the second voltage relay J2 and the DC voltage source 31, so that the intermediate relay J3 controls the switch K1 on this side to open and the bus tie switch K2 to close, and the device will switch to the bus in the opposite station d supply power to the busbar c in the local station; when the collected three-phase voltage values U11, U12, and U13 of the incoming power line a of the local station are normal, that is, U11, U12, and U13 are all greater than the preset voltage threshold, the first voltage The relay J1 is disconnected, so that the intermediate relay J3 is disconnected, and the circuit formed by the intermediate relay J3, the first voltage relay J1, the second voltage relay J2 and the DC voltage source 31 is disconnected, so that the intermediate relay J3 controls the switch K1 on this side to close And the control bus tie switch K3 is turned off, and the device will switch back to the power supply line a of the station on this side to supply power to the bus c in the station on this side.

As shown in Fig. 4, the embodiment of the present invention also provides a method for automatic emergency switching of the substation power system, which is implemented in the aforementioned device for automatic emergency switching of the substation power system, and the method includes:

Step S101, collecting in real time the three-phase voltage value of the incoming power line for the station on the local side, the three-phase voltage value of the incoming power line for the opposite station, and the three-phase current value of the bus in the station on the local side;

Step S102: Determine the current working mode according to the three-phase current value of the bus in the station on the local side collected in real time, and send a corresponding level signal according to the determined current working mode; wherein, the current The working mode includes a protection mode and a normal mode, the level signal corresponding to the protection mode is a low level signal, and the level signal corresponding to the normal mode is a high level signal;

The specific process is that the protection mode includes over-current protection mode and zero-sequence protection mode. When any of the three-phase current values of the bus in the station on the local side collected in real time is greater than the preset first current threshold, the current working mode is determined. It is an overcurrent protection mode and sends a low-level signal; when one-third of the sum of the three-phase current values of the three-phase current values of the bus in the station on this side collected in real time is greater than the preset second current threshold, it is determined that the current The working mode is the zero-sequence protection mode, and a low-level signal is sent; when any current value of the three-phase current value of the bus in the local station collected in real time is less than the preset first current threshold and the three-phase current value of the sum of the three-phase current values When one-half is less than the preset second current threshold, it is determined that the current working mode is the normal mode, and a high level signal is sent.

Step S103, receiving the sent level signal, and judging the switching between lines supplying power to the bus in the local station according to the level of the received level signal;

The specific process is that when the received level signal is a high-level signal, switching between the lines that supply power to the bus in the station on this side can be realized; Switching between bus powered lines is not possible.

Step S104, when switching between the lines supplying power to the bus in the local station can be realized, according to the real-time collected three-phase voltage values of the incoming power lines for the local station and the incoming power lines for the opposite station Determine the size of the power supply for the station on the current side or the internal bus on the opposite side to supply power to the internal bus on the local side.

The specific process is that switching between the lines that supply power to the bus in the local station can be realized, and at least one phase voltage value of the three-phase voltage value of the incoming power line of the local station collected in real time is less than the preset voltage threshold and the When the voltage value of each phase of the three-phase voltage value of the power supply incoming line for the side station is greater than the preset voltage threshold, it is determined to enable the busbar in the opposite station to supply power to the busbar in the station;

When switching between the lines supplying power to the bus in the local station can be realized, and when the three-phase voltage value of each phase voltage value of the incoming power line of the local station collected in real time is greater than the preset voltage threshold, it is determined to enable the local station The station uses the power supply incoming line to supply power to the bus in the station on this side.

Implementing the embodiment of the present invention has the following beneficial effects:

1. In the embodiment of the present invention, because the current transformer in the device is based on the Rogowski coil, the net weight is extremely low, the installation is simple and the disassembly is convenient, which overcomes the shortcomings of the traditional current transformer, which is fixed in the installation position and difficult to disassemble.

2. In the embodiment of the present invention, since the device contains a sampling unit, a protection unit and a logic control unit, its structure is simple and easy to maintain, and the sampling unit is completely independent, which is convenient for the operation and maintenance personnel to quickly install and debug, and avoids The risk of long-term voltage loss of the busbar also has the protection functions of zero-sequence protection and over-current protection.

3. In the embodiment of the present invention, since the device can be installed in any substation station power system bus AC incoming line screen, it is used to replace the traditional standby automatic switching device in emergency, which overcomes the waste of resources and turnover caused by the traditional way of storing spare parts Disadvantages of long time.

It is worth noting that in the above system embodiments, the system units included are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be realized; in addition, the specific functions of each functional unit The names are only for the convenience of distinguishing each other, and are not used to limit the protection scope of the present invention.

Those of ordinary skill in the art can understand that all or part of the steps in the method of the above-mentioned embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, and the storage Media such as ROM/RAM, magnetic disk, optical disk, etc.

The above disclosure is only a preferred embodiment of the present invention, which certainly cannot limit the scope of rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope of the present invention.

Claims (10)

1. The emergency device for the spare power automatic switching of the power system of the transformer substation is characterized by comprising a sampling unit, a protection unit, a switch transistor and a logic control unit; wherein,

one end of the sampling unit is connected with one end of the protection unit, the other end of the sampling unit is connected with the source electrode of the switch transistor, and the sampling unit comprises a local side switch, a bus-coupled switch, a voltage sampling module and a current sampling module; the two ends of the local side switch are respectively connected with the power incoming line for the local side station and the bus in the local side station; one end of the bus coupler switch is connected with a bus in the opposite side station, and the other end of the bus coupler switch is connected with the bus in the local side station; the two ends of the voltage sampling module are respectively connected with the power inlet wire for the local side station and the power inlet wire for the opposite side station, and are used for acquiring the three-phase voltage values of the power inlet wire for the local side station and the power inlet wire for the opposite side station in real time; the current sampling module is connected with the bus in the station at the side and is used for acquiring the three-phase current value of the bus in the station at the side in real time;

the other end of the protection unit is connected with a grid electrode of the switch transistor and is used for determining a current working mode according to the real-time collected three-phase current value of the bus in the station at the side and sending a corresponding level signal to the switch transistor according to the determined current working mode; the current working mode comprises a protection mode and a normal mode, wherein the level signal corresponding to the protection mode is a low level signal, and the level signal corresponding to the normal mode is a high level signal;

the drain electrode of the switching transistor is connected with the logic control unit and used for realizing the connection or disconnection between the sampling unit and the logic control unit according to the level of the level signal sent by the protection unit;

and the logic control unit is used for determining to start the power inlet wire for the local side station or the power supply for the bus in the opposite side station to supply power to the bus in the local side station according to the real-time collected three-phase voltage values of the power inlet wire for the local side station and the power inlet wire for the opposite side station when being conducted with the sampling unit.

2. The substation station power system spare power automatic switching emergency device according to claim 1, wherein the logic control unit comprises a first voltage relay, a second voltage relay, an intermediate relay and a direct current voltage source; the first voltage relay, the second voltage relay and the intermediate relay are connected in series to form a circuit, and the circuit formed by the series connection of the first voltage relay, the second voltage relay and the intermediate relay is connected in parallel with the direct-current voltage source;

the first voltage relay is used for determining whether the power supply incoming line is in an open state or a closed state according to the real-time collected three-phase voltage value of the power supply incoming line for the local side station when the first voltage relay is conducted with the sampling unit;

the second voltage relay is used for determining whether the power supply incoming line is in an open state or a closed state according to the real-time collected three-phase voltage value of the power supply incoming line for the opposite side station when the second voltage relay is conducted with the sampling unit;

and the intermediate relay is used for determining whether the intermediate relay is in an open state or a closed state according to the determined open-close states of the first voltage relay and the second voltage relay when the intermediate relay is conducted with the sampling unit, so that the open-close states of the local side switch and the bus connection switch are controlled, and the power supply inlet of the local side station or the power supply of the bus in the local side station is determined to be started.

3. The emergency standby power automatic switching device for the substation electric system according to claim 2, wherein when the sampling unit is turned on, and at least one of the real-time collected three-phase voltage values of the incoming line of the local side substation power supply is smaller than a preset voltage threshold, and each of the three-phase voltage values of the incoming line of the opposite side substation power supply is larger than the preset voltage threshold, the first voltage relay and the second voltage relay are both closed, so that the intermediate relays are closed, the circuits formed by the serial connection form a connection circuit, the intermediate relays control the local side switch to be opened and control the bus connection switch to be closed, and the opposite side substation internal bus is determined to be started to supply power to the local side substation internal bus.

4. The emergency device for the backup power automatic switching of the electric system for the substation according to claim 2, wherein when the sampling unit is turned on and each phase voltage value of the real-time collected three-phase voltage values of the power inlet line of the local side station is greater than a preset voltage threshold value, the first voltage relay is turned off, so that the intermediate relay is turned off, and thus a circuit formed by the phases in series is in an off state, the intermediate relay controls the local side switch to be closed and controls the bus coupler switch to be opened, and the power inlet line of the local side station is enabled to supply power to the bus in the local side station.

5. The substation power system spare power automatic switching emergency device of claim 1, wherein the protection mode comprises an overcurrent protection mode and a zero sequence protection mode; wherein,

when any current value of the three-phase current values of the bus in the local station acquired in real time is larger than a preset first current threshold value, the protection unit enters an overcurrent protection mode, controls the local switch to be switched off, and sends a low-level signal to the switching transistor, so that the switching transistor is switched off, and the sampling unit and the logic control unit are switched off;

when one third of the sum of three-phase current values in the three-phase current values of the bus in the station at the side collected in real time is larger than a preset second current threshold value, the protection unit enters a zero sequence protection mode, controls the switch at the side to be switched off, and sends a low level signal to the switching transistor, so that the switching transistor is switched off, and the sampling unit and the logic control unit are switched off.

6. The device for the backup power automatic switching emergency of the electric system for the substation according to any one of claims 1 to 5, wherein the current sampling module comprises three current transformers, and the three current transformers are current transformers based on Rogowski coils and are respectively sleeved with three-phase cables of the bus in the local side station one by one.

7. The emergency device for the backup power automatic switching of the electric system for the substation according to claim 6, wherein the voltage sampling module comprises six voltage fuses, wherein three voltage fuses are respectively connected with the three-phase incoming lines of the power supply for the local side station one by one, and the other three voltage fuses are respectively connected with the three-phase incoming lines of the power supply for the opposite side station one by one.

8. A method for emergency backup automatic switching of an electric system for a substation, which is implemented in the device for emergency backup automatic switching of an electric system for a substation according to any one of claims 1 to 7, the method comprising:

acquiring a three-phase voltage value of a power supply incoming line for a local side station, a three-phase voltage value of the power supply incoming line for the opposite side station and a three-phase current value of a bus in the local side station in real time;

determining a current working mode according to the real-time acquired three-phase current value of the bus in the station at the side, and sending a corresponding level signal according to the determined current working mode; the current working mode comprises a protection mode and a normal mode, wherein the level signal corresponding to the protection mode is a low level signal, and the level signal corresponding to the normal mode is a high level signal;

receiving the sent level signal, and judging the switching condition between lines for supplying power to the bus in the station at the side according to the level of the received level signal;

when the switching between the lines for supplying power to the buses in the local side station can be realized, the power inlet wire for the local side station or the buses in the opposite side station are determined to be started to supply power to the buses in the local side station according to the real-time collected three-phase voltage values of the power inlet wire for the local side station and the power inlet wire for the opposite side station.

9. The method as claimed in claim 8, wherein the specific steps of determining a current operation mode according to the real-time collected three-phase current values of the bus in the local station, and sending a corresponding level signal according to the determined current operation mode include:

when any current value of the three-phase current values of the bus in the station at the side, which are acquired in real time, is larger than a preset first current threshold value, determining that the current working mode is an overcurrent protection mode in a protection mode, and sending the low level signal;

when one third of the sum of three-phase current values in the three-phase current values of the bus in the station at the side, which are acquired in real time, is greater than a preset second current threshold value, determining that the current working mode is a zero-sequence protection mode in a protection mode, and sending the low-level signal;

and when any current value of the three-phase current values of the bus in the station collected in real time is smaller than the preset first current threshold value and one third of the sum of the three-phase current values is smaller than the preset second current threshold value, determining that the current working mode is a normal mode, and sending the high-level signal.

10. The method according to claim 8, wherein when switching between lines for supplying power to the bus in the local station is possible, the specific step of determining to enable the power inlet line for the local station or the bus in the opposite station to supply power to the bus in the local station according to the real-time collected three-phase voltage values of the power inlet line for the local station and the power inlet line for the opposite station includes:

when at least one phase voltage value in the three-phase voltage values of the power supply incoming line for the local side station acquired in real time is smaller than a preset voltage threshold value and each phase voltage value in the three-phase voltage values of the power supply incoming line for the opposite side station is larger than the preset voltage threshold value, determining to start the internal bus of the opposite side station to supply power to the internal bus of the local side station;

and when each phase voltage value in the real-time acquired three-phase voltage values of the power supply inlet wire for the local side station is larger than a preset voltage threshold value, determining to start the power supply inlet wire for the local side station to supply power to the bus in the local side station.