CN104037934B - Spare power automatic switching emergency device and method for power utilization system of transformer substation - Google Patents
Spare power automatic switching emergency device and method for power utilization system of transformer substation Download PDFInfo
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- CN104037934B CN104037934B CN201410270736.0A CN201410270736A CN104037934B CN 104037934 B CN104037934 B CN 104037934B CN 201410270736 A CN201410270736 A CN 201410270736A CN 104037934 B CN104037934 B CN 104037934B
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Abstract
The invention provides a spare power automatic switching emergency device of an electric system for a transformer substation, which comprises a sampling unit, a protection unit, a switch transistor and a logic control unit, wherein the sampling unit is used for sampling a power supply voltage; a local side switch in the sampling unit is connected with a local side power supply inlet wire and a bus, a bus-bar switch is connected with the opposite side bus, a voltage sampling module is connected with the opposite side power supply inlet wire, and a current sampling module is connected with the local side bus; the protection unit is connected with the sampling unit and used for determining a working mode and sending a level signal to the switching transistor according to the current value of the bus at the side; the switching transistors are respectively connected with the three units and are used for realizing the on-off according to the level signals; and the logic control unit is used for determining to start the incoming line of the power supply at the side or the bus at the opposite side to supply power to the bus at the side according to the three-phase voltage value of the incoming line of the power supply at the opposite side when the switching transistor is switched on. The invention has simple structure and quick disassembly, avoids the risk of long-time voltage loss of the bus at the side and saves a large amount of financial resources and time.
Description
Technical Field
The invention relates to the technical field of power utilization systems of power system transformer substations, in particular to a spare power automatic switching emergency device and method for the power utilization systems of the transformer substations.
Background
As shown in fig. 1, the substation power system provides a stable and reliable 380V ac power supply for ac loads in the substation, and it is usually configured that a first-stage bus a 'and a second-stage bus b' are operated in a split-row manner, the first-stage bus a 'and the second-stage bus b' are respectively led from the low-voltage sides of two stand-by transformers, i.e., the first-stage bus a 'is supplied with power from a 10KV ac power supply through a #1 station incoming line of a power supply P1 transformed by an up-switch ST1 of the station-use transformer and other transformation devices, and the second-stage bus b' is supplied with power from a 10KV ac power supply through a #2 station incoming line of a power supply P2 transformed by an up-switch ST2 of the station-use transformer and other transformation devices. When the section I bus a ' loses the incoming line power supply of the power supply P1 for the station #1, namely the incoming line switch 1QF of the station #1 fails and is disconnected, the spare power automatic switching device N1 in the bus alternating current incoming line screen M1 installed in the station #1 is switched to the section II bus b ' powered by the incoming line of the power supply P2 for the station #2 through closing the bus coupler 3QF, so that the voltage loss of the section I bus a ' is avoided; when the bus b ' at the section II loses the incoming line power supply of the power supply P2 for the station #2, namely the incoming line switch 2QF of the station #2 fails and is disconnected, the spare power automatic switching device N2 in the bus alternating current incoming line screen M2 installed in the station #2 is switched to the bus a ' at the section I powered by the incoming line power supply P1 for the station #1 through closing the bus coupler 3QF, and the voltage loss of the bus b ' at the section II is avoided.
At present, the substation power consumption system spare power automatic switching device is widely used in each substation of a power system, the device relates to too many manufacturers and too complex product types, and the device has the following defects: 1. because the number of manufacturers is too many, once the device fails, the device needs to return to different manufacturers for replacement, a great amount of time is wasted, and particularly, the time for waiting for upgrading and updating is too long because the production of the devices of partial models is stopped, so that the risk of the bus voltage loss of the station power utilization system is increased; 2. the product types are too complex to facilitate maintenance, and a large amount of spare devices for each product type need to be reserved to ensure that device failures can be quickly resolved, thereby wasting a large amount of financial resources.
Disclosure of Invention
The technical problem to be solved by the embodiment of the invention is to provide a device and a method for emergency backup power automatic switching of an electric system for a substation, which can be used for replacing the traditional backup power automatic switching device in emergency, have simple structure and convenient maintenance, and avoid the risk of long time voltage loss of a bus in the substation at the side, thereby saving a large amount of financial resources and time and providing guarantee for safe and stable operation of the electric system for the substation.
In order to solve the technical problem, an embodiment of the invention provides an emergency device for a spare power automatic switching of an electric system of a transformer substation, which comprises a sampling unit, a protection unit, a switch transistor and a logic control unit, wherein the sampling unit is used for sampling a voltage signal of the spare power automatic switching; 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 coupler 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.
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 that the logic control unit is in an open or closed state according to the real-time collected three-phase voltage value of the power incoming line for the local station when the logic control unit is connected with the sampling unit;
the second voltage relay is used for determining that the logic control unit is in an open or closed state according to the real-time collected three-phase voltage value of the incoming line of the power supply for the opposite station when the logic control unit is connected with the sampling unit;
and the intermediate relay is used for determining that the logic control unit is in an open or closed state according to the determined open and closed states of the first voltage relay and the second voltage relay when the logic control unit is conducted with the sampling unit, so that the open and closed 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 opposite side station is determined to be started.
When the logic control unit is connected with the sampling unit, and at least one phase voltage value in the three-phase voltage values of the power incoming line for the local side station, which is 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 incoming line for the local side station is larger than the preset voltage threshold value, the first voltage relay and the second voltage relay are both closed, so that the intermediate relay is closed, a circuit formed by the serial connection of the phase voltages forms a connection circuit, and when the sampling unit is connected, the intermediate relay controls the local side switch to be disconnected and controls the bus connection switch to be closed, and the bus in the opposite side station is determined to be started to supply power to the bus in the local side station.
When the logic control unit is connected with the sampling unit and each phase voltage value in the power supply inlet wire three-phase voltage values for the local side station acquired in real time is larger than a preset voltage threshold value, the first voltage relay is disconnected, so that the intermediate relay is disconnected, a circuit formed by connecting the local side station with the intermediate relay is in a disconnected state, when the logic control unit is connected with the sampling unit, the intermediate relay controls the local side switch to be closed and controls the bus connection switch to be disconnected, and the local side station power supply inlet wire is enabled to supply power to the bus in the local side station.
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.
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 the three-phase cables of the buses in the side station one by one.
The voltage sampling module comprises six voltage fuses, wherein the three voltage fuses are respectively connected with the three-phase incoming lines of the power supply for the 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 side station one by one.
The embodiment of the invention also provides a method for emergency of the spare power automatic switching of the electric system for the transformer substation, which is realized in the device for emergency of the spare power automatic switching of the electric system for the transformer substation, and the method comprises the following steps:
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.
The specific steps of determining the current working mode according to the real-time collected three-phase current value of the bus in the station at the side and sending the corresponding level signal according to the determined current working 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.
When the switching between the lines for supplying power to the bus in the local side station can be realized, the specific steps of starting the power inlet wire for the local side station or supplying power to the bus in the opposite 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 comprise:
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.
The embodiment of the invention has the following beneficial effects:
1. in the embodiment of the invention, because the current transformer in the device is based on the Rogowski coil, the net weight is extremely low, the installation is simple, the disassembly is convenient, and the defects of fixed installation position and difficult disassembly of the traditional current transformer are overcome.
2. In the embodiment of the invention, because the device comprises the sampling unit, the protection unit and the logic control unit, the device has simple structure and convenient maintenance, and the sampling unit is completely independent, thereby being convenient for operation and maintenance personnel to rapidly install and debug, avoiding the risk of long-time voltage loss of the bus in the station at the side and having the protection functions of zero sequence protection and overcurrent protection.
3. In the embodiment of the invention, the device can be arranged in the bus alternating current inlet screen of the electric system of any substation, and is used for replacing the traditional spare power automatic switching device in emergency, so that the defects of resource waste and long turnover time caused by spare parts storage in the traditional mode are overcome.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is within the scope of the present invention for those skilled in the art to obtain other drawings based on the drawings without inventive exercise.
Fig. 1 is a schematic view of an application scenario of a standby power automatic switching device of a 380V main-to-side station power utilization system in the prior art;
fig. 2 is a schematic structural diagram of a spare power automatic switching emergency device of an electric system for a substation according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of the logic control unit shown in FIG. 2;
fig. 4 is a flowchart of a method for emergency standby power automatic switching of an electric system of a substation provided by the embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.
As shown in fig. 2, an emergency device for the backup power automatic switching of the electric system for the substation is provided in an incoming screen of any substation to switch between the power supply for the local substation and the power supply for the opposite substation. The emergency device for the spare power automatic switching of the power system of the transformer substation comprises 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 with one end of the protection unit 2, the other end is connected with a source electrode S of the switch transistor 3, and the sampling unit comprises a local side switch K1, a bus-coupled switch K2, a voltage sampling module 11 and a current sampling module 12; two ends of a local side switch K1 are respectively connected with a power inlet wire a for a local side station and a local side station internal bus c; one end of a bus coupler switch K2 is connected with a bus d in the opposite side station, and the other end is connected with a bus c in the side station; the two ends of the voltage sampling module 11 are respectively connected with a power supply incoming line a for the local side station and a power supply incoming line b for the opposite side station, and are used for acquiring three-phase voltage values of the power supply incoming line a for the local side station and the power supply incoming line b for the opposite side station in real time; the current sampling module 12 is connected with the bus c in the station at the side and is used for collecting the three-phase current value of the bus c in the station at the side in real time;
the other end of the protection unit 2 is connected with a grid G of the switch transistor 3, and is used for determining a current working mode according to the real-time collected three-phase current value of the bus c in the station at the side and sending a corresponding level signal to the switch transistor 3 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 D of the switching transistor 3 is connected with the logic control unit 4 and is used for realizing the connection or disconnection between the sampling unit 1 and the logic control unit 4 according to the level of the level signal sent by the protection unit 2;
and the logic control unit 4 is used for determining to start the power supply incoming line a for the local side station or the power supply incoming line b for the opposite side station according to the real-time acquired three-phase voltage values of the power supply incoming line a for the local side station and the power supply incoming line b for the opposite side station when the sampling unit 1 is conducted.
It should be noted that the voltage obtained by transforming the voltage of the power supply inlet wire a for the local side station or the voltage of the bus d in the opposite side station can meet the voltage use requirement of the bus c in the local side station.
In the whole device, the voltage sampling module 11 in the sampling unit 1 comprises six voltage fuses, wherein three voltage fuses are used for collecting the three-phase voltage value of the power supply incoming line a for the side station in real time, the three voltage fuses are respectively connected with the three-phase incoming line of the power supply for the side station one by one, in addition, three voltage fuses are also used for collecting the three-phase voltage value of the power supply incoming line b for the side station in real time, the three voltage fuses are also respectively connected with the three-phase incoming line of the power supply for the side station one by one, the six voltage fuses are identical in structure, and the range of the collected voltage value is between 0V and 460V.
The current sampling module 12 in the sampling unit 1 includes three current transformers for acquiring the three-phase current value of the bus c in the station on the side in real time, the three current transformers are all current transformers based on rogowski coils, and are respectively sleeved with the three-phase cables of the bus c in the station on the side one by one, and the range of the current value capable of being acquired is between 0A and 2500A. Because the net weight of each current transformer is extremely low, the installation is simple and the disassembly is convenient, the defects that the traditional current transformer is fixed in installation position and difficult to disassemble are overcome, and therefore the sampling unit 1 with the independent module and the switch design is provided, the structure is simple, the rapid installation and debugging of operation and maintenance personnel are convenient, and the risk of long-time voltage loss of the bus c of the power utilization system of the side station is avoided.
No matter the local side switch K1 of the local side station is closed and the bus tie switch K2 is opened, a stable and reliable 380V alternating current power supply is provided for the bus c in the local side station after the local side station power supply incoming line a is transformed, or the local side switch K1 of the local side station is opened and the bus tie switch K2 is closed, the stable and reliable 380V alternating current power supply is provided for the bus c in the local side station through the bus d in the opposite side station, the three-phase current value of the bus c in the local side station can be collected in real time by the current sampling module 12 in the sampling unit 1, the current working mode is determined by the protection unit 2 according to the size of the three-phase current value of the bus c in the local side station collected in real time by the sampling module 12, and the corresponding level signal is sent to the switch transistor 3 according to the determined current working.
When any current value of three-phase current values of a bus c in the station at the side, which are acquired in real time, is larger than a first current threshold value preset in the protection unit 2, the protection unit 2 enters an overcurrent protection mode, controls a switch K1 at the side to be disconnected, 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 one third of the sum of three current values in the three-phase current value of the bus c in the station at the side, which is acquired in real time, is greater than a second current threshold value preset in the protection unit 2, the protection unit 2 enters a zero sequence protection mode, controls the switch K1 at the side to be switched off, and sends a low level signal to the switching transistor 3, so that the switching transistor 3 is switched off, and the switching-off between the sampling unit 1 and the logic control unit 4 is realized; when the two protection modes are started, the connection between the sampling unit 1 and the logic control unit 4 is cut off, so that the power supply inlet wire a for the local side station and the power supply for the bus c in the opposite side station are cut off, and the spare power automatic switching function of the device is locked.
When any current value of the three-phase current values of the bus c in the station at the side, which are acquired in real time, is smaller than a first current threshold value preset in the protection unit 2, and one third of the total three-phase current value is smaller than a second current threshold value preset in the protection unit 2, the protection unit 2 keeps a current normal mode, and sends a high-level signal to the switching transistor 3, so that the switching transistor 3 is closed, and the connection 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 the protection mode is enabled, no matter whether the power incoming line a for the local side station is enabled or the internal bus d of the opposite side station is enabled to supply power to the internal bus c of the local side station, the power supply mode of the internal bus c of the local side station is maintained to be the power supply mode before the protection mode is enabled by the protection unit 2.
In order to control the on-off state of the local side switch K1 and the bus-coupled switch K2 by the logic control unit 4 when the local side switch K1 and the bus-coupled switch K2 are turned on with the sampling unit 1, so that the effect of switching to the bus d in the opposite side station when the power supply incoming line a for the local side station fails is achieved, as shown in fig. 3, a relay protection circuit is adopted 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 direct current voltage source 31; the first voltage relay J1, the second voltage relay J2 and the intermediate relay J3 are connected in series to form a relay protection circuit, and the circuit formed by the series connection is connected with the direct-current voltage source 31 in parallel;
the first voltage relay J1 is used for determining whether the power supply incoming line a is in an open or closed state according to the magnitude of the real-time collected three-phase voltage value of the power supply incoming line a for the local side station when the power supply incoming line a is conducted with the sampling unit 1;
the second voltage relay J2 is used for determining whether the power supply incoming line b is in an open or closed state according to the magnitude of the three-phase voltage value of the power supply incoming line b for the opposite station acquired in real time when the power supply incoming line b is connected with the sampling unit 1;
and the intermediate relay J3 is used for determining that the sampling unit is in an open or closed state according to the determined open and closed states of the first relay J1 and the second relay J2 when the sampling unit 1 is conducted, so that the open and closed states of the local side switch K1 and the bus coupler K2 are controlled, and the power supply incoming line a for the local side station or the power supply of the internal bus d of the opposite side station is determined to be started to supply power to the internal bus c of the local side station.
When the sampling unit 1 is switched on and at least one of three-phase voltage values of a power supply incoming line a for a local side station acquired in real time is smaller than a preset voltage threshold and each of three-phase voltage values of a power supply incoming line b for the opposite side station is larger than the preset voltage threshold, the first voltage relay J1 and the second voltage relay J2 are both closed, the intermediate relay J3 is closed, a circuit formed by the serial connection of the two circuits forms a connection circuit, the intermediate relay J3 controls the disconnection of the switch K1 and the closing of the bus-bar switch K2, and the fact that the bus d in the opposite side station is started to supply power to the bus c in the local side station is determined.
When the sampling unit 1 is switched on and each voltage value in the three-phase voltage values of the power supply inlet wire a for the local side station acquired in real time is larger than a preset voltage threshold value, the first voltage relay J1 is switched off, so that the intermediate relay J3 is switched off, a circuit formed by the serial connection of the two is in an off state, the intermediate relay J3 controls the local side switch K1 to be switched on and controls the bus-tie switch K2 to be switched off, and the power supply inlet wire a for the local side station is enabled to supply power for the bus c in the local side station.
Further, dc voltage source 31 includes 110V dc power source and 220V dc power source, and when 220V dc power source is adopted, a voltage converter is required for converting 220V dc voltage into 110V dc voltage.
As an example, three voltage fuses are additionally arranged on an incoming cable of a power supply for a local side station, three-phase voltage values U11, U12 and U13 of an incoming line a of the power supply for the local side station are acquired, the three voltage fuses are additionally arranged on the incoming cable of the power supply for an opposite side station, three-phase voltage values U21, U22 and U23 of an incoming line b of the power supply for the opposite side station are acquired, three current transformers are additionally arranged on a 380V bus c in the local side station, and three-phase current values Ia, Ib and Ic of the 380V bus c in the local side station are acquired;
when any one of the collected three-phase current values Ia, Ib and Ic of the bus c in the station at the side is larger than a built-in overcurrent protection fixed value (namely larger than a preset first current threshold), overcurrent protection is started, the switch K1 at the side is controlled to be switched off, and a low level signal is sent to the switching transistor 3, so that the switching transistor 3 is switched off, and the functions of switching off between the sampling unit 1 and the logic control unit 4 and switching on and off the spare power automatic switching of the locking device are realized; when one third of the sum of the three current values Ia, Ib and Ic of the collected three-phase current value of the bus c is greater than the built-in zero sequence protection fixed value (i.e. greater than the preset second current threshold value), the zero sequence protection is started to control the local side switch K1, and a low level signal is sent to the switching transistor 3, so that the switching transistor 3 is switched off, and the functions of switching off between the sampling unit 1 and the logic control unit 4 and switching on and off the spare power automatic switching of the locking device are realized;
when the sampling unit 1 is connected with the logic control unit 4, the device can realize the spare power automatic switching function, when at least one of the collected three-phase voltage values U11, U12 and U13 of the incoming line a of the power supply for the local side station is smaller than a preset voltage threshold (such as 20 percent of the original voltage value), the first voltage relay J1 is closed, the collected three-phase voltage values U21, U22 and U23 of the incoming line b of the power supply for the opposite side station are normal in voltage, namely U21, U22 and U23 are all larger than the preset voltage threshold, the second voltage relay J2 is closed, the intermediate relay J1 and the second voltage relay J2 are closed, so that the intermediate relay J3 is excited and closed, the intermediate relay J3, the first voltage relay J1, the second voltage relay J2 and the direct-current voltage source 31 form a connection circuit, and the intermediate relay J3 controls the local side switch K1 to be opened and controls the bus tie switch 2 to be closed, the device switches to the bus d in the opposite side station to supply power to the bus c in the side station; when the collected three-phase voltage values U11, U12 and U13 of the power incoming line a for the station at the side are normal, namely the voltages of U11, U12 and U13 are all larger than a preset voltage threshold value, the first voltage relay J1 is disconnected, the intermediate relay J3 is disconnected, a circuit formed by the intermediate relay J3, the first voltage relay J1, the second voltage relay J2 and the direct-current voltage source 31 is in an off state, the intermediate relay J3 controls the switch K1 at the side to be closed and controls the bus coupler K3 to be disconnected, and the device switches the power incoming line a for the power supply to the bus c in the station at the side back.
As shown in fig. 4, an embodiment of the present invention further provides a method for emergency standby power automatic switching of an electric system for a substation, which is implemented in the foregoing device for emergency standby power automatic switching of an electric system for a substation, and the method includes:
s101, 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;
step S102, 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 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 method comprises the following steps that a protection mode comprises an overcurrent protection mode and a zero sequence protection mode, when any current value of three-phase current values of a bus in a station on the current side, which are acquired in real time, is larger than a preset first current threshold value, the current working mode is determined to be the overcurrent protection mode, and a low level signal is sent; 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 larger than a preset second current threshold value, determining that the current working mode is a zero sequence protection mode, and transmitting a low level signal; and when any current value of the three-phase current values of the bus in the station at the side, which is acquired in real time, is smaller than a preset first current threshold value and one third of the sum of the three-phase current values is smaller than a preset second current threshold value, determining that the current working mode is a normal mode, and transmitting a high-level signal.
Step S103, receiving the sent level signal, and judging the switching condition between lines supplying power to the bus in the station at the side 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 can be realized between lines for supplying power to the bus in the station at the side; when the received level signal is a low level signal, the switching between the lines supplying power to the bus in the station at the side cannot be realized.
And S104, when switching between lines for supplying power to the bus in the local side station can be realized, determining to start the power inlet wire for the local side station or 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.
The method comprises the specific processes that switching can be achieved among lines for supplying power to the bus in the local station, and when at least one phase voltage value in the three-phase voltage values of the power incoming line for the local station, which are 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 incoming line for the opposite station is larger than the preset voltage threshold value, the bus in the opposite station is determined to be started to supply power to the bus in the local station;
switching can be achieved among lines for supplying power to the bus in the station at the side, and when each phase voltage value in the three-phase voltage values of the power inlet wire for the station at the side, which are acquired in real time, is larger than a preset voltage threshold value, the power inlet wire for the station at the side is determined to be started to supply power to the bus in the station at the side.
The embodiment of the invention has the following beneficial effects:
1. in the embodiment of the invention, because the current transformer in the device is based on the Rogowski coil, the net weight is extremely low, the installation is simple, the disassembly is convenient, and the defects of fixed installation position and difficult disassembly of the traditional current transformer are overcome.
2. In the embodiment of the invention, because the device comprises the sampling unit, the protection unit and the logic control unit, the device has simple structure and convenient maintenance, and the sampling unit is completely independent, thereby being convenient for operation and maintenance personnel to rapidly install and debug, avoiding the risk of long-time voltage loss of the bus in the station at the side and having the protection functions of zero sequence protection and overcurrent protection.
3. In the embodiment of the invention, the device can be arranged in the bus alternating current inlet screen of the electric system of any substation, and is used for replacing the traditional spare power automatic switching device in emergency, so that the defects of resource waste and long turnover time caused by spare parts storage in the traditional mode are overcome.
It should be noted that, in the foregoing system embodiment, each included system unit is only divided according to functional logic, but is not limited to the above division as long as the corresponding function can be implemented; in addition, specific names of the functional units are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present invention.
It will be understood by those skilled in the art that all or part of the steps in the method for implementing the above embodiments may be implemented by relevant hardware instructed by a program, and the program may be stored in a computer-readable storage medium, such as ROM/RAM, magnetic disk, optical disk, etc.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
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 coupler 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 that the logic control unit is in an open or closed state according to the real-time collected three-phase voltage value of the power incoming line for the local station when the logic control unit is connected with the sampling unit;
the second voltage relay is used for determining that the logic control unit is in an open or closed state according to the real-time collected three-phase voltage value of the incoming line of the power supply for the opposite station when the logic control unit is connected with the sampling unit;
and the intermediate relay is used for determining that the logic control unit is in an open or closed state according to the determined open and closed states of the first voltage relay and the second voltage relay when the logic control unit is conducted with the sampling unit, so that the open and closed 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 opposite 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 logic control unit is turned on with the sampling unit, and at least one phase voltage value of the real-time collected three-phase voltage values of the local substation power supply inlet wire is smaller than a preset voltage threshold value, and each phase voltage value of the three-phase voltage values of the opposite substation power supply inlet wire is larger than the preset voltage threshold value, 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 connected circuit, the intermediate relays control the local side switch to be opened and control the bus connection switch to be closed, and the opposite substation internal bus is determined to be started to supply power to the local side station 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 logic control unit is turned on with the sampling unit, and each phase voltage value of the real-time collected three-phase voltage values of the incoming line of the power supply for 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, the circuit formed by the serial connection of the phases is in an off state, the intermediate relay controls the local side switch to be closed and controls the bus tie switch to be opened, and the incoming line of the power supply for the local side station is determined to be started to supply power to the bus line 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.
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| CN108668415B (en) * | 2017-03-28 | 2020-06-16 | 杭州海康威视数字技术股份有限公司 | Mode switching method and device of intelligent lighting equipment |
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