CN112186720A - High-speed short circuit current limiting device - Google Patents
High-speed short circuit current limiting device Download PDFInfo
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- CN112186720A CN112186720A CN202010855729.2A CN202010855729A CN112186720A CN 112186720 A CN112186720 A CN 112186720A CN 202010855729 A CN202010855729 A CN 202010855729A CN 112186720 A CN112186720 A CN 112186720A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
- H02G13/00—Installations of lightning conductors; Fastening thereof to supporting structure
- H02G13/80—Discharge by conduction or dissipation, e.g. rods, arresters, spark gaps
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
- H02H9/021—Current limitation using saturable reactors
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment
Abstract
The invention discloses a high-speed short-circuit current limiting device, and relates to the field of current limiters. It includes current monitoring control unit, installs high speed switch and current limiting unit on the bus, its characterized in that: the device also comprises a voltage monitoring control unit; the high-speed switch and the current limiting unit are connected in parallel and then are connected into a bus. The invention has the beneficial effects that: the amplitude and the duration of the fault current are reduced to the maximum extent, the influence of the fault current on a system is reduced, the on-off reliability is improved, and the cost of the device is reduced.
Description
Technical Field
The invention relates to the technical field of current limiters, in particular to a high-speed short-circuit current limiting device.
Background
When a short-circuit fault occurs in an electric power system, the short-circuit current rises to dozens of times of rated current in a short time (generally about 20 ms), and the level of the short-circuit current is continuously increased along with the expansion of a power grid, so that serious threat is brought to the power grid, and the development of the electric power system is restricted. Therefore, effective measures must be taken to limit the short-circuit fault current.
The problem that the short-circuit current exceeds the standard increasingly seriously is faced, a plurality of enterprises limit the short-circuit current of the system by adopting a high-impedance transformer, but the problem of current limiting depth is not finally solved by increasing the impedance of the transformer, the electric power is reduced a little, and active and reactive power loss and investment cost rise are brought.
The fault current limiter is used as a technical scheme for limiting short-circuit fault current, and can effectively limit the level of the short-circuit current in a power grid. Wherein the fault current limiter has the following advantages: on one hand, dynamic and thermal stability burden of various high-voltage electrical equipment such as a circuit breaker and the like can be reduced, and safe and stable operation of a power grid is ensured; on the other hand, the design capacity of the power grid structure can be significantly reduced. Therefore, the research on the novel fault current limiter with excellent performance and economic reasonability has important practical significance and application value.
The currently available fault current limiters mainly include the following:
(1) the current-limiting reactor is connected in series to the system, however, the problem of current-limiting depth (reactance rate is about ten percent) is not fundamentally solved by adopting the series current-limiting reactor, and simultaneously, the defects of active and reactive power loss, bus voltage drop, magnetic leakage field and the like are brought, when the system is in short circuit, the current-limiting depth is not enough, main electrical equipment such as a generator, a transformer and the like cannot be effectively protected, and a winding is deformed and damaged under the impact of huge short-circuit current, so that catastrophic accidents occur.
(2) However, in the current limiting process, the potential problem of magnetic flux saturation caused by the fact that the transformer bears excessive short-circuit current needs to be avoided.
(3) Solid-state current limiter: switched solid state current limiters, however, this solution is costly and requires the protection circuit to have a very fast response speed; resonant solid state current limiters, however, introduce inductive and capacitive elements that increase the likelihood of system oscillations and overvoltages.
(4) However, in the scheme, a current-limiting resistor is adopted to limit fault current, and the problem of resistance heating exists under the current-limiting working condition.
(5) The explosive type high-capacity high-speed cut-off device used in the market and the reactor are operated in parallel, so that the problems of active and reactive power loss, voltage drop and magnetic leakage field of the reactor are solved, but when a short-circuit fault occurs, the primary component acts, and the problem of current limiting depth is not solved when the reactor is put into operation. This type of device requires replacement of new spare parts in order to be able to be put into operation again.
The above current limiting scheme limits its application in practical systems due to various drawbacks.
In the prior art, a cycle of 20 milliseconds is required for general microcomputer protection sampling; 30 milliseconds are needed for fast FFT calculation and command sending; the inherent opening time of the common circuit breaker is more than 50 milliseconds; when the arc time after the on-off reaches about ten milliseconds, the current can pass through zero arc quenching. It takes about 100 milliseconds to cut off the short circuit current. The long-time short-circuit current has extremely high requirements on dynamic and thermal stability of equipment such as transformers, buses, switches, generators and the like. In addition, the current limiting device only collects the amplitude change of the current generally, but the action of the current limiting device is greatly delayed because the amplitude change of the current generally lags behind the change of the voltage.
Therefore, the current limiting device capable of rapidly and reliably limiting the short-circuit current deeply is developed, which is very important for safe and reliable operation of a power system and also very important for reducing the equipment cost of an electrical equipment use factory.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a high-speed short-circuit current limiting device aiming at the technical defects. The method aims to reduce the amplitude and the duration of fault current to the maximum extent, reduce the influence of the fault current on a system, increase the reliability of switching on and off and reduce the cost of the device.
The technical scheme adopted by the invention is as follows: the utility model provides a high-speed short circuit current limiting device, including current monitoring control unit, install high-speed switch and the current limiting unit on the generating line, its characterized in that: the device also comprises a voltage monitoring control unit;
the high-speed switch is connected with the current limiting unit in parallel and then is connected into a bus;
the current monitoring control unit is in signal connection with the high-speed switch; the voltage monitoring control unit is in signal connection with the high-speed switch;
the high-speed switch is used for receiving a command of transmitting switching-off/switching-on sent by the current monitoring control unit and/or the voltage monitoring control unit and immediately executing switching-off/switching-on operation.
Further optimizing the technical scheme, the high-speed switch of the high-speed short-circuit current limiting device is a high-speed eddy current driving switch.
Further optimizing the technical scheme, the current limiting unit of the high-speed short-circuit current limiting device is a current limiting reactor.
Further optimizing the technical scheme, the high-speed short-circuit current limiting device also comprises a lightning arrester; the lightning arrester and the current-limiting reactor are connected to a bus in parallel.
Further optimizing the technical scheme, the voltage acquisition equipment of the voltage monitoring control unit access line of the high-speed short-circuit current limiting device is a voltage transformer.
Further optimizing the technical scheme, the current monitoring and controlling unit of the high-speed short-circuit current limiting device comprises a current sampling subunit, a fault detection subunit, a strategy judgment subunit and a signal transmission subunit; the current sampling subunit acquires sampling values of three currents of the system and then transmits the sampling values to the fault detection subunit;
the fault detection subunit performs fault detection on the sampling value, acquires a fault detection result and transmits the detection result to the strategy judgment subunit after the fault detection result and the fault occurrence moment are acquired;
the strategy judgment subunit selects a corresponding high-speed switch on-off strategy according to the fault detection result and then transmits the on-off strategy to the signal transmission subunit;
the signal transmission subunit transmits the high-speed switch on-off strategy to a high-speed switch.
Further optimizing the technical scheme, the strategy decision subunit of the high-speed short-circuit current limiting device selects the following strategies:
(1) if only one fault phase exists in the three-phase current, independently switching on and off by respectively taking the predicted zero-crossing point of each phase as a switching-on and switching-off target;
(2) if two fault phases exist in the three-phase current, the minimum predicted zero crossing point of the two fault phases is taken as a disconnection target, the two fault phases are disconnected simultaneously, and the third phase is independently disconnected according to the predicted zero crossing point of the third phase as the disconnection target;
(3) if three-phase faults exist in the three-phase current, the earliest zero-crossing phase is taken as a first-opened phase and is switched on and off according to the minimum predicted zero-crossing point as a target, and the remaining two phases are switched on and off simultaneously by taking the minimum predicted zero-crossing point of a second zero-crossing phase as a switching-on and switching-off target.
Further optimizing the technical scheme, the voltage monitoring control unit of the high-speed short-circuit current-limiting device comprises a voltage sampling subunit, a fault detection subunit, a strategy judgment subunit and a signal transmission subunit;
the voltage sampling subunit acquires sampling values of three currents of the system and then transmits the sampling values to the fault detection subunit;
the fault detection subunit performs fault detection on the sampling value, acquires a fault detection result and transmits the detection result to the strategy judgment subunit after the fault detection result and the fault occurrence moment are acquired;
the strategy judgment subunit selects a corresponding high-speed switch on-off strategy according to the fault detection result and then transmits the on-off strategy to the signal transmission subunit;
the signal transmission subunit transmits the high-speed switch on-off strategy to a high-speed switch.
Further optimizing the technical scheme, when the three-phase voltage of the high-speed short-circuit current limiting device is an angular connection winding, the strategy decision subunit selects the following strategies:
(1) when only one fault phase exists in the three-phase voltage, if the voltage of one phase is reduced to be below 30 percent Un, and the voltage of the other two phases is higher than the rated voltage, the single-phase grounding short circuit is judged. The breaker does not act;
(2) when an inter-phase fault occurs in three phases, if the voltage of two phases is reduced to be below 30% Un and the voltage of the other phase is higher than the rated voltage, the inter-phase grounding short circuit occurs between the two phases with the reduced voltage, the quick circuit breaker of the phase with the reduced voltage is disconnected, and the quick circuit breaker is disconnected when the current prediction result of the phase with the increased voltage is zero.
(3) And when all the three-phase voltages are in short circuit fault, if the three-phase voltages are reduced to be below 30% Un, the three-phase grounding short circuit is judged. The quick breaker opens.
Further optimizing the technical scheme, when the three-phase voltage of the high-speed short-circuit current limiting device is a star-shaped wiring winding, the strategy decision subunit selects the following strategies:
(1) when only one fault phase exists in three-phase voltage, if the voltage of one phase is reduced to be below 30% Un, the single-phase grounding short circuit is judged, the fault phase fast breaker firstly acts, and the other two phases are disconnected when the current crosses zero;
(2) when only two fault phases exist in three-phase voltage, if one-phase voltage is reduced to be below 30% Un, the two-phase grounding short circuit is judged, the fault-phase quick circuit breaker firstly acts, and the other one phase is disconnected when the current crosses zero;
(3) when only three fault phases exist in three-phase voltage, if one-phase voltage is reduced to be below 30% Un, the three-phase grounding short circuit is judged, and the three-phase quick breaker acts firstly.
The invention has the following remarkable beneficial effects:
1. under normal working conditions, the invention has small loss, current flows through the high-speed switch branch circuit, and the two ends of the current limiter are short-circuited, thereby basically having no influence on the whole circuit system.
2. Under the short-circuit fault working condition, the voltage monitoring control unit is adopted as the trigger of the current limiting device, the short-circuit fault monitoring time can be shortened to be within 1ms, and the starting and stopping time (3 ms) of the high-speed switch is combined, so that the duration time of the short-circuit current can be controlled to be within 4ms, the impact of the peak value of the first cycle (10 ms) on the power equipment can be greatly reduced, and compared with the independent current monitoring control, the voltage monitoring control method is more sensitive to short circuit, the response time is shorter, and the effect of reducing the short-circuit current of the transformer is more obvious.
3. The current monitoring control unit and the voltage monitoring control unit are arranged in the short-circuit protection circuit, the voltage monitoring control unit and the current monitoring control unit can both play a role in monitoring the short-circuit current, the voltage monitoring control unit plays a role firstly if the short-circuit current occurs because the voltage monitoring control unit is more sensitive to the short-circuit current than the current monitoring control unit, the current monitoring control unit plays a role in backup protection, and the current monitoring control unit can also monitor the short-circuit current after the voltage monitoring control unit goes wrong.
4. The invention can replace high-impedance transformer, common series current-limiting reactor, explosion type large-capacity high-speed cut-off device, when designing new power supply system and modifying enterprise system, the high-speed short-circuit current-limiting device of the invention can be used to increase system impedance, further reduce cut-off current of load side breaker, and reduce cost.
Drawings
FIG. 1 is a block diagram of the frame of the present invention;
fig. 2 is a schematic view of the connection of the arrester and the current limiting reactor of the present invention;
FIG. 3 is a block diagram of the current monitoring and control unit frame of the present invention;
FIG. 4 is a block diagram of the voltage monitoring control unit frame of the present invention;
in the figure, 1, a current monitoring control unit; 2. a high-speed switch; 3. a current limiting unit; 4. and a voltage monitoring control unit.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Example I:
as shown in fig. 1, the technical solution of this embodiment is: the utility model provides a high-speed short circuit current limiting device, includes current monitoring control unit 1, installs high-speed switch 2 and current limiting unit 3 on the generating line, its characterized in that: the device also comprises a voltage monitoring control unit 4;
the high-speed switch 2 and the current limiting unit 3 are connected in parallel and then are connected into a bus;
the current monitoring control unit 1 is in signal connection with the high-speed switch 2; the voltage monitoring control unit 4 is in signal connection with the high-speed switch 2;
the high-speed switch 2 is used for receiving a command for transmitting switching-off/switching-on sent by the current monitoring control unit 1 and/or the voltage monitoring control unit 4 and immediately executing switching-off/switching-on operation.
When the embodiment is used:
after short-circuit current appears in the bus, the voltage monitoring control unit 4 can monitor the voltage variation of the bus, the voltage monitoring control unit 4 sends a received signal to the high-speed switch 2, the signal is a switching-off or switching-on command, and after the high-speed switch 2 receives the signal sent by the voltage monitoring control unit 4, switching-off or switching-on operation can be immediately executed.
After short-circuit current appears in the bus, the current monitoring and control unit 1 can monitor the current variation of the bus, the current monitoring and control unit 1 sends a received signal to the high-speed switch 2, the signal is a switching-off or switching-on command, and after the high-speed switch 2 receives the signal sent by the current monitoring and control unit 1, switching-off or switching-on operation can be immediately executed.
When no short-circuit fault occurs in the system, the impedance of the current limiting unit 3 is minimum; when the system has short-circuit fault, the current limiting unit 3 has large impedance; when the short-circuit fault of the system is cleared, the voltage monitoring control unit 4 or the current monitoring control unit 1 sends a closing signal to the high-speed switch 2, the high-speed switch 2 performs closing operation, and the system immediately returns to the original working state.
At the initial stage that short-circuit current appears, voltage monitoring control unit 4 detects the voltage variation in the generating line fast, and voltage monitoring control unit 4 or current monitoring control unit 1 send the signal of switching off to high-speed switch 2, and high-speed switch 2 carries out the switching off operation, puts into current limiting unit 3 fast, with short-circuit current restriction in reliable scope to the mesh of protection distribution equipment and power supply line has been reached.
Example II:
the example is the same as the embodiment I:
the utility model provides a high-speed short circuit current limiting device, includes current monitoring control unit 1, installs high-speed switch 2 and current limiting unit 3 on the generating line, its characterized in that: the device also comprises a voltage monitoring control unit 4;
the high-speed switch 2 and the current limiting unit 3 are connected in parallel and then are connected into a bus;
the current monitoring control unit 1 is in signal connection with the high-speed switch 2; the voltage monitoring control unit 4 is in signal connection with the high-speed switch 2;
the high-speed switch 2 is used for receiving a command for transmitting switching-off/switching-on sent by the current monitoring control unit 1 and/or the voltage monitoring control unit 4 and immediately executing switching-off/switching-on operation.
This example differs from the scheme of example i in that:
as shown in fig. 2, the current limiting unit 3 is a current limiting reactor;
the lightning arrester also comprises a lightning arrester; the lightning arrester and the current-limiting reactor are connected to a bus in parallel;
the lightning arrester can effectively protect the current-limiting reactor from being damaged by lightning stroke, and can prolong the service life of the current-limiting reactor.
Example III:
this example is the same as the embodiment I:
the utility model provides a high-speed short circuit current limiting device, includes current monitoring control unit 1, installs high-speed switch 2 and current limiting unit 3 on the generating line, its characterized in that: the device also comprises a voltage monitoring control unit 4;
the high-speed switch 2 and the current limiting unit 3 are connected in parallel and then are connected into a bus;
the current monitoring control unit 1 is in signal connection with the high-speed switch 2; the voltage monitoring control unit 4 is in signal connection with the high-speed switch 2;
the high-speed switch 2 is used for receiving a command for transmitting switching-off/switching-on sent by the current monitoring control unit 1 and/or the voltage monitoring control unit 4 and immediately executing switching-off/switching-on operation.
This example differs from the embodiment i in that:
as shown in fig. 3, the current monitoring and controlling unit 1 includes a current sampling subunit, a fault detecting subunit, a strategy deciding subunit and a signal transmitting subunit;
the current sampling subunit acquires sampling values of three currents of the system and then transmits the sampling values to the fault detection subunit;
the fault detection subunit performs fault detection on the sampling value, acquires a fault detection result and transmits the detection result to the strategy judgment subunit after the fault detection result and the fault occurrence moment are acquired;
the strategy judgment subunit selects a corresponding high-speed switch 2 switching-on and switching-off strategy according to the fault detection result and then transmits the switching-on and switching-off strategy to the signal transmission subunit;
the signal transmission subunit transmits the on-off strategy of the high-speed switch 2 to the high-speed switch 2;
the strategy decision subunit selects the following strategies:
(1) if only one fault phase exists in the three-phase current, independently switching on and off by respectively taking the predicted zero-crossing point of each phase as a switching-on and switching-off target;
(2) if two fault phases exist in the three-phase current, the minimum predicted zero crossing point of the two fault phases is taken as a disconnection target, the two fault phases are disconnected simultaneously, and the third phase is independently disconnected according to the predicted zero crossing point of the third phase as the disconnection target;
(3) if three-phase faults exist in the three-phase current, the earliest zero-crossing phase is taken as a first open phase, the three-phase current is switched on and switched off according to the minimum predicted zero-crossing point as a target, and the remaining two phases are switched on and switched off simultaneously by taking the minimum predicted zero-crossing point of the second zero-crossing phase as a switching-on and switching-off target;
the current sampling subunit is used for acquiring the sampling value of the three-phase current of the system, the current sampling subunit transmits the sampling value to the fault detection subunit,
the fault detection subunit performs fault detection on the sampling value, acquires a fault detection result and a fault occurrence time,
the fault detection subunit transmits the signal to the strategy judgment subunit, and the strategy judgment subunit selects a corresponding high-speed switch 2 on-off strategy according to the fault detection result. The method specifically comprises the following steps:
(1) if only one fault phase exists in the three-phase current, independently switching on and off by respectively taking the predicted zero-crossing point of each phase as a switching-on and switching-off target;
(2) if two fault phases exist in the three-phase current, the minimum predicted zero crossing point of the two fault phases is taken as a disconnection target, the two fault phases are disconnected simultaneously, and the third phase is independently disconnected according to the predicted zero crossing point of the third phase as the disconnection target;
(3) if three-phase faults exist in the three-phase current, the earliest zero-crossing phase is taken as a first phase and is switched on and off according to the minimum predicted zero-crossing point as a target, and the remaining two phases are switched on and off simultaneously by taking the minimum predicted zero-crossing point of a second zero-crossing phase as a switching-on and switching-off target;
and finally, the strategy judgment subunit transmits the final judgment signal to the signal transmission subunit, the signal transmission subunit transmits the final judgment signal to the high-speed switch 2, and the high-speed switch 2 can perform switching-on or switching-off operation to effectively protect the circuit.
Example IV:
this example is the same as the embodiment I:
the utility model provides a high-speed short circuit current limiting device, includes current monitoring control unit 1, installs high-speed switch 2 and current limiting unit 3 on the generating line, its characterized in that: the device also comprises a voltage monitoring control unit 4;
the high-speed switch 2 and the current limiting unit 3 are connected in parallel and then are connected into a bus;
the current monitoring control unit 1 is in signal connection with the high-speed switch 2; the voltage monitoring control unit 4 is in signal connection with the high-speed switch 2;
the high-speed switch 2 is used for receiving a command for transmitting switching-off/switching-on sent by the current monitoring control unit 1 and/or the voltage monitoring control unit 4 and immediately executing switching-off/switching-on operation.
This example differs from the embodiment i in that:
as shown in fig. 4, the voltage monitoring and controlling unit 4 includes a voltage sampling subunit, a fault detecting subunit, a strategy deciding subunit and a signal transmitting subunit;
the voltage sampling subunit acquires sampling values of three currents of the system and then transmits the sampling values to the fault detection subunit;
the fault detection subunit performs fault detection on the sampling value, acquires a fault detection result and transmits the detection result to the strategy judgment subunit after the fault detection result and the fault occurrence moment are acquired;
the strategy judgment subunit selects a corresponding high-speed switch 2 switching-on and switching-off strategy according to the fault detection result and then transmits the switching-on and switching-off strategy to the signal transmission subunit;
the signal transmission subunit transmits the high-speed switch 2 switching-off strategy to the high-speed switch 2.
When the three-phase voltage is a corner connection winding, the strategy decision subunit selects the following strategy:
(1) when only one fault phase exists in the three-phase voltage, if the voltage of one phase is reduced to be below 30 percent Un, and the voltage of the other two phases is higher than the rated voltage, the single-phase grounding short circuit is judged. The breaker does not need to be operated;
(2) when an inter-phase fault occurs in three phases, if the voltage of two phases is reduced to be below 30% Un and the voltage of the other phase is higher than the rated voltage, the inter-phase grounding short circuit occurs between the two phases with the reduced voltage, the quick circuit breaker of the phase with the reduced voltage is disconnected, and the quick circuit breaker is disconnected when the current prediction result of the phase with the increased voltage is zero.
(3) And when all the three-phase voltages are in short circuit fault, if the three-phase voltages are reduced to be below 30% Un, the three-phase grounding short circuit is judged. The quick breaker opens.
When the three-phase voltage is a star-shaped wiring winding, the strategy decision subunit selects the following strategies:
(1) when only one fault phase exists in three-phase voltage, if the voltage of one phase is reduced to be below 30% Un, the single-phase grounding short circuit is judged, the fault phase fast breaker firstly acts, and the other two phases are disconnected when the current crosses zero;
(2) when only two fault phases exist in three-phase voltage, if one-phase voltage is reduced to be below 30% Un, the two-phase grounding short circuit is judged, the fault-phase quick circuit breaker firstly acts, and the other one phase is disconnected when the current crosses zero;
(3) when only three fault phases exist in three-phase voltage, if one-phase voltage is reduced to be below 30% Un, the three-phase grounding short circuit is judged, and the three-phase quick breaker acts firstly.
And a voltage sampling subunit is utilized to obtain a sampling value of the three-phase current of the system, and the voltage sampling subunit transmits the sampling value to the fault detection subunit.
The fault detection subunit performs fault detection on the sampling value, acquires a fault detection result and a fault occurrence time,
the fault detection subunit transmits the signal to the strategy judgment subunit, and the strategy judgment subunit selects a corresponding high-speed switch 2 on-off strategy according to the fault detection result: the method specifically comprises the following steps:
when the three-phase voltage is a corner connection winding, the strategy decision subunit selects the following strategy:
(1) when only one fault phase exists in the three-phase voltage, if the voltage of one phase is reduced to be below 30 percent Un, and the voltage of the other two phases is higher than the rated voltage, the single-phase grounding short circuit is judged. The breaker does not need to be operated;
(2) when an inter-phase fault occurs in three phases, if the voltage of two phases is reduced to be below 30% Un and the voltage of the other phase is higher than the rated voltage, the inter-phase grounding short circuit occurs between the two phases with the reduced voltage, the quick circuit breaker of the phase with the reduced voltage is disconnected, and the quick circuit breaker is disconnected when the current prediction result of the phase with the increased voltage is zero.
(3) And when all the three-phase voltages are in short circuit fault, if the three-phase voltages are reduced to be below 30% Un, the three-phase grounding short circuit is judged. The quick breaker opens.
When the three-phase voltage is a star-shaped wiring winding, the strategy decision subunit selects the following strategies:
(1) when only one fault phase exists in three-phase voltage, if the voltage of one phase is reduced to be below 30% Un, the single-phase grounding short circuit is judged, the fault phase fast breaker firstly acts, and the other two phases are disconnected when the current crosses zero;
(2) when only two fault phases exist in three-phase voltage, if one-phase voltage is reduced to be below 30% Un, the two-phase grounding short circuit is judged, the fault-phase quick circuit breaker firstly acts, and the other one phase is disconnected when the current crosses zero;
(3) when only three fault phases exist in three-phase voltage, if one-phase voltage is reduced to be below 30% Un, the three-phase grounding short circuit is judged, and the three-phase quick breaker acts firstly.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
The relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
In the description of the present application, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are used for convenience of description and simplicity of description only, and in the case of not making a reverse description, these directional terms do not indicate and imply that the device or element being referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore, should not be considered as limiting the scope of the present application; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.
Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of protection of the present application is not to be construed as being limited.
Claims (10)
1. The utility model provides a high-speed short circuit current limiting device, includes current monitoring control unit (1), installs high-speed switch (2) and current limiting unit (3) on the generating line, its characterized in that: the device also comprises a voltage monitoring control unit (4); the high-speed switch (2) and the current limiting unit (3) are connected in parallel and then are connected into a bus; the current monitoring control unit (1) is in signal connection with the high-speed switch (2); the voltage monitoring control unit (4) is in signal connection with the high-speed switch (2); the high-speed switch (2) is used for receiving a command for transmitting switching-off/switching-on sent by the current monitoring control unit (1) and/or the voltage monitoring control unit (4) and immediately executing switching-off/switching-on operation.
2. A high speed short circuit current limiting device according to claim 1, wherein: the high-speed switch (2) is a high-speed eddy current driving switch.
3. A high speed short circuit current limiting device according to claim 1, wherein: the current limiting unit (3) is a current limiting reactor.
4. A high speed short circuit current limiting device according to claim 3, wherein: the lightning arrester also comprises a lightning arrester; the lightning arrester and the current-limiting reactor are connected to a bus in parallel.
5. A high speed short circuit current limiting device according to claim 1, wherein: and the voltage acquisition equipment of the access circuit of the voltage monitoring control unit (4) is a voltage transformer.
6. A high speed short circuit current limiting device according to claim 1, wherein: the current monitoring and controlling unit (1) comprises a current sampling subunit, a fault detecting subunit, a strategy judging subunit and a signal transmission subunit;
the current sampling subunit acquires sampling values of three currents of the system and then transmits the sampling values to the fault detection subunit;
the fault detection subunit performs fault detection on the sampling value, acquires a fault detection result and transmits the detection result to the strategy judgment subunit after the fault detection result and the fault occurrence moment are acquired;
the strategy judgment subunit selects a corresponding on-off strategy of the high-speed switch (2) according to the fault detection result and then transmits the on-off strategy to the signal transmission subunit;
the signal transmission subunit transmits the high-speed switch (2) switching strategy to the high-speed switch (2).
7. A high speed short circuit current limiting device according to claim 6, wherein: the strategy decision subunit selects the following strategies:
(1) if only one fault phase exists in the three-phase current, independently switching on and off by respectively taking the predicted zero-crossing point of each phase as a switching-on and switching-off target;
(2) if two fault phases exist in the three-phase current, the minimum predicted zero crossing point of the two fault phases is taken as a disconnection target, the two fault phases are disconnected simultaneously, and the third phase is independently disconnected according to the predicted zero crossing point of the third phase as the disconnection target;
(3) if three-phase faults exist in the three-phase current, the earliest zero-crossing phase is taken as a first-opened phase and is switched on and off according to the minimum predicted zero-crossing point as a target, and the remaining two phases are switched on and off simultaneously by taking the minimum predicted zero-crossing point of a second zero-crossing phase as a switching-on and switching-off target.
8. A high speed short circuit current limiting device according to claim 1, wherein: the voltage monitoring control unit (4) comprises a voltage sampling subunit, a fault detection subunit, a strategy judgment subunit and a signal transmission subunit;
the voltage sampling subunit acquires sampling values of three currents of the system and then transmits the sampling values to the fault detection subunit;
the fault detection subunit performs fault detection on the sampling value, acquires a fault detection result and transmits the detection result to the strategy judgment subunit after the fault detection result and the fault occurrence moment are acquired;
the strategy judgment subunit selects a corresponding on-off strategy of the high-speed switch (2) according to the fault detection result and then transmits the on-off strategy to the signal transmission subunit;
the signal transmission subunit transmits the high-speed switch (2) switching strategy to the high-speed switch (2).
9. A high speed short circuit current limiting device according to claim 8, wherein: when the three-phase voltage is a corner connection winding, the strategy decision subunit selects the following strategy:
(1) when only one fault phase exists in the three-phase voltage, if the voltage of one phase is reduced to be below 30 percent Un, the voltage of the other two phases is higher than the rated voltage, and the single-phase grounding short circuit is judged; the breaker does not need to be operated;
(2) when an interphase fault occurs in three phases, if the voltage of a two-phase is reduced to be below 30% Un and the voltage of the other one-phase is higher than the rated voltage, judging that an interphase grounding short circuit occurs between the two phases with the reduced voltage, and the quick circuit breaker of the phase with the reduced voltage is disconnected, and when the current prediction result of the phase with the increased voltage is zero, the quick circuit breaker is disconnected;
(3) when all three-phase voltages are in short circuit fault, if the three-phase voltages are reduced to be below 30% Un, the three-phase voltages are judged to be in grounding short circuit; the quick breaker opens.
10. A high speed short circuit current limiting device according to claim 8, wherein: when the three-phase voltage is a star-shaped wiring winding, the strategy decision subunit selects the following strategies:
(1) when only one fault phase exists in three-phase voltage, if the voltage of one phase is reduced to be below 30% Un, the single-phase grounding short circuit is judged, the fault phase fast breaker firstly acts, and the other two phases are disconnected when the current crosses zero;
(2) when only two fault phases exist in three-phase voltage, if one-phase voltage is reduced to be below 30% Un, the two-phase grounding short circuit is judged, the fault-phase quick circuit breaker firstly acts, and the other one phase is disconnected when the current crosses zero;
(3) when only three fault phases exist in three-phase voltage, if one-phase voltage is reduced to be below 30% Un, the three-phase grounding short circuit is judged, and the three-phase quick breaker acts firstly.
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| JP2002118950A (en) * | 2000-10-05 | 2002-04-19 | Tokyo Electric Power Co Inc:The | Fault-detecting protective device for rectifier-type current limiting device |
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