CN108512203B - Distribution network protection device and method - Google Patents
Distribution network protection device and method Download PDFInfo
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- CN108512203B CN108512203B CN201810555404.5A CN201810555404A CN108512203B CN 108512203 B CN108512203 B CN 108512203B CN 201810555404 A CN201810555404 A CN 201810555404A CN 108512203 B CN108512203 B CN 108512203B
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- 238000006243 chemical reaction Methods 0.000 claims abstract description 27
- 238000004891 communication Methods 0.000 claims abstract description 27
- 238000002955 isolation Methods 0.000 claims abstract description 11
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- 230000003111 delayed effect Effects 0.000 claims description 5
- 235000008113 selfheal Nutrition 0.000 abstract 1
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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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Abstract
The invention provides a distribution network protection device and method, wherein the protection device and method comprises a circuit breaker, a double-side voltage detection unit, a current detection unit, an opening and closing unit, a digital-to-analog conversion component, a central processing unit, a controller, an input and output unit and a communication unit, wherein the circuit breaker is connected with the double-side voltage detection unit, the current detection unit, the opening and closing unit and the controller, the double-side voltage detection unit and the current detection unit are respectively connected with the digital-to-analog conversion component, the digital-to-analog conversion component is connected with the central processing unit, the central processing unit is connected with the opening and closing unit, the input and output unit and the communication unit, the opening and closing unit is connected with the controller, and the protection device and method automatically judge distribution network faults, isolate fault areas and control the distribution network to self-heal. The distribution network protection device has the advantages that: the automatic isolation of various faults of the distribution network and the automatic power supply of non-fault areas are completed rapidly, accurately and reliably without depending on wired communication and on the switching cooperation of a plurality of circuit breakers.
Description
Technical Field
The invention relates to a protection device and method, in particular to a distribution network protection device and method, and belongs to the technical field of relay protection and automation of power distribution networks of power systems.
Background
The intelligent power grid has the characteristics of reliability, high quality, high efficiency, compatibility, interaction and the like, is the development direction of a modern power grid, and receives high attention from the domestic and foreign electric power industry. In recent years, to summarize the experience training of several times of blackouts in the world, domestic and foreign experts and enterprises improve the self-healing capacity of a large-scale power transmission network, and a great deal of research is performed to improve the safety and stability level of the power transmission network, so that a series of research results are obtained. But the development and research of the automatic protection capability of the power distribution network are less in the prior art.
The power distribution network in China generally adopts a neutral point small current grounding mode, after single-phase grounding faults, no obvious short-circuit current exists, but the voltage of non-fault phases rises, fault sections are difficult to identify and rapidly isolate, and huge threats are caused to people and equipment near the grounding points. For a long time, single-phase earth faults cannot be isolated rapidly and effectively, so that human electric shock accidents, especially social personnel electric shock casualties, occur. The power distribution network is directly oriented to users, and the short circuit and ground fault isolation and self-healing capacity of the power distribution network can directly influence the power supply quality of the power distribution network to the users. Circuit breakers are important devices in a power distribution network, and fault isolation of the power distribution network can be achieved through control of the circuit breakers.
In view of the foregoing, it is desirable to provide a distribution network protection device and method, which can overcome the drawbacks of the prior art.
Disclosure of Invention
The invention aims to provide a distribution network protection device and a distribution network protection method, which can overcome the defects of the prior art. The invention aims at achieving the following technical scheme.
One embodiment of the invention provides a distribution network protection device, wherein the protection device comprises a circuit breaker, a double-sided voltage detection unit, a current detection unit, an opening and closing unit, a digital-to-analog conversion component, a central processing unit, a controller, an input and output unit and a communication unit, the controller comprises a switching-on control component, the circuit breaker is connected with the double-sided voltage detection unit, the current detection unit, the opening and closing unit and the controller, the double-sided voltage detection unit and the current detection unit are respectively connected with the digital-to-analog conversion component, the digital-to-analog conversion component is connected with the central processing unit, the central processing unit is connected with the opening and closing unit, the input and output unit and the communication unit, the opening and closing unit is connected with the controller, the double-sided voltage detection unit is used for detecting respective phase voltages and respective zero sequence voltages on three wires of two ends of the circuit breaker, the current detection unit is used for detecting respective phase currents and three-wire currents on the circuit breaker, the opening and closing control component is used for detecting position contacts of the circuit breaker and transmitting signals of the central processing unit to the controller, and the switching-on control component is used for sending and receiving locking signals after charging.
According to the distribution network protection device provided by the embodiment of the invention, the protection device comprises:
the double-side voltage detection unit detects voltages UA, UB, UC,3UO at two ends of the circuit breaker and transmits detection results to the central processing unit through the digital-to-analog conversion component, and the current detection unit detects currents IA, IB and IC and transmits detection results to the central processing unit through the digital-to-analog conversion component; and
the central processing unit executes the segment breaker monitoring/self-healing process.
According to the distribution network protection device provided by the embodiment of the invention, the monitoring/self-healing process of the segmented circuit breaker comprises the following steps:
the double-side voltage detection unit detects voltages UA, UB, UC,3UO at two ends of the circuit breaker and transmits detection results to the central processing unit through the digital-to-analog conversion component, and the current detection unit detects currents IA, IB, IC,3IO and transmits detection results to the central processing unit through the digital-to-analog conversion component;
judging whether a single-phase earth fault occurs by the central processing unit according to 3UO and 3I0 of the circuit breaker, and if so, controlling the circuit breaker to trip in a delay manner through the switching-in switching-out unit and the controller by the central processing unit; if not, judging whether a three-phase symmetrical fault occurs according to the IA, IB and IC of the circuit breaker, and if so, controlling the circuit breaker to trip in a delay way by the CPU through the on-off unit and the controller; if not, the central processing unit judges whether two-phase asymmetric faults occur according to the IA, IB and IC of the circuit breaker, and if so, the central processing unit controls the circuit breaker to trip in a delay way through the opening and closing unit and the controller; if not, the central processing unit judges whether the three-phase voltage loss condition is met or not and the fault current is generated according to UA, UB, UC,3UO,IA,IB,IC of the circuit breaker, and if so, the central processing unit controls the circuit breaker to trip in a delay mode through the opening and closing unit and the controller; if not, the central processing unit judges whether the three-phase voltage loss condition is met according to UA, UB, UC and 3UO of the circuit breaker;
the central processing unit judges whether the three-phase voltage-losing conditions are met according to UA, UB, UC and 3UO of the circuit breaker, if so, the central processing unit judges whether the preset three-phase voltage-losing tripping delay time is reached, and if so, the central processing unit controls the circuit breaker to delay tripping through the opening-closing unit and the controller; if not, the central processing unit judges whether the fault residual voltage is detected, if not, the central processing unit judges whether the preset three-phase voltage-loss tripping delay time is reached again; if yes, the communication unit sends a blocking signal to a lower relay far away from the power end, then the central processing unit judges whether the communication unit receives the blocking signal sent by an upper relay close to the power end, if yes, the device returns, if not, the central processing unit judges whether the preset blocking signal waiting time is reached, if yes, the circuit breaker trips, the switching-on controller discharges, and the input and output unit outputs blocking switching-on information; if not, the central processing unit judges whether a locking signal sent by an upper relay close to the power end is received again;
the double-side voltage detection unit detects voltages UA, UB, UC,3UO at two ends of the circuit breaker and transmits detection results to the central processing unit through the digital-to-analog conversion component;
the central processing unit judges whether the circuit breaker has voltage on one side, if so, the central processing unit judges whether the voltage is instantaneous residual voltage, if so, the switching-on controller discharges, and the input and output unit outputs locking switching-on information; if not, the central processing unit controls the delay closing of the circuit breaker through the opening-in-opening-out unit and the controller; the method comprises the steps of,
and judging whether the circuit breaker is switched on in a fault state, if so, accelerating tripping of the circuit breaker, discharging the switching-on controller, and outputting locking and switching-on information by the input and output unit.
According to the distribution network protection device provided by the embodiment of the invention, the distribution network protection device further comprises a sequential quick-action function and a weak feed protection function which are started after two-phase asymmetric faults occur, whether the sequential quick-action function and the weak feed protection function are effective or not is set through an input-output unit, the sequential quick-action function is used for accelerating isolation of a fault distribution network, the weak feed protection function is used for tripping instantaneously on the opposite sides of a fault point when a near-outlet fault occurs on the power supply side of a distribution network circuit, and the fault power supply side continuously senses the fault and simultaneously senses the change of electric quantity again to accelerate tripping.
According to the distribution network protection device provided by the embodiment of the invention, the delay tripping of the circuit breaker comprises the step of presetting different delay times according to the processing speed of the communication unit, the installation position of the circuit breaker and the fault type.
According to the distribution network protection device provided by the embodiment of the invention, the delayed closing of the circuit breaker comprises the step of presetting different delay times according to different circuit materials, arc extinguishing time and user properties.
One embodiment of the present invention provides a protection method for a distribution network, where the protection method includes a plurality of steps:
step 1: detecting voltages UA, UB, UC,3UO, detecting currents IA, IB, IC at two ends of the circuit breaker and detecting the switch position state of the circuit breaker; and
step 2: and performing a segment breaker monitoring/self-healing process.
According to the distribution network protection method provided by the embodiment of the invention, the monitoring/self-healing process of the segmented circuit breaker comprises the following steps:
step 3: detecting voltages UA, UB, UC,3UO at two ends of the circuit breaker, and detecting currents IA, IB, IC,3IO;
step 4: judging whether single-phase earth faults occur according to 3UO and 3I0 of the circuit breaker, if so, executing the step 7; if not, judging whether a three-phase symmetrical fault occurs according to the IA and IB of the circuit breaker, and if so, executing the step 7; if not, judging whether two-phase asymmetric faults occur according to the IA and IB of the circuit breaker, and if so, executing the step 7; if not, judging whether the three-phase voltage loss condition is met or not and the fault current is generated according to UA, UB, UC,3UO,IA,IB,IC of the circuit breaker, if so, executing the step 7; if not, judging whether the three-phase voltage loss condition is met according to UA, UB, UC,3UO of the circuit breaker, and if not, executing the step 3; if yes, executing the step 5;
step 5: judging whether the preset three-phase voltage-loss tripping delay time is reached, if so, executing the step 8; if not, judging whether the fault residual pressure is detected, and if not, executing the step 5; if yes, a locking signal is sent to a lower relay far away from a power end, and then, the step 6 is executed;
step 6: judging whether a locking signal sent by an upper relay close to a power end is received or not, if not, executing the step 7; if yes, executing the step 1;
step 7: judging that the preset blocking signal waiting time is reached, if yes, tripping the circuit breaker, discharging, and outputting blocking and closing information; if not, executing the step 6 again;
step 8: delay tripping of the circuit breaker;
step 9: detecting voltages UA, UB, UC,3UO at two ends of the circuit breaker;
step 10: judging whether the circuit breaker is pressed on one side, if so, executing the step 11; if not, executing the step 8;
step 11: judging whether the voltage is instantaneous residual voltage, if so, discharging and outputting locking and closing information; if not, the circuit breaker is switched on in a delay way, and then the step 12 is executed; the method comprises the steps of,
step 12: judging whether the breaker is switched on in a fault state, if so, accelerating tripping, discharging and outputting locking and switching-on information; if not, executing the step 1.
According to the distribution network protection method provided by the embodiment of the invention, after the occurrence of the two-phase asymmetric fault, the distribution network protection method further comprises the steps of starting a 'sequential quick-action' function and a 'weak feed protection' function, wherein whether the 'sequential quick-action' function and the 'weak feed protection' function take effect or not is set through an input-output unit, the 'sequential quick-action' function is used for accelerating the isolation of the fault distribution network, the 'weak feed protection' function is used for conducting instantaneous tripping on the opposite sides of a fault point when the near-outlet fault of a power supply side of a distribution network circuit occurs, and the fault power supply side continuously senses the fault and simultaneously senses the change of electric quantity again to accelerate tripping.
According to the distribution network protection method provided by the embodiment of the invention, the delay tripping of the circuit breaker comprises the step of presetting different delay times according to the processing speed of the communication unit, the installation position of the circuit breaker and the fault type.
According to the distribution network protection method provided by the embodiment of the invention, the delayed closing of the circuit breaker comprises the step of presetting different delay times according to different circuit materials, arc extinguishing time and user properties.
The distribution network protection device has the advantages that: the method does not depend on wired communication, does not depend on protection and reclosing cooperation of a 10kV line outlet of a transformer substation, does not depend on secondary superposition, does not depend on switching cooperation of a plurality of circuit breakers, and does not suffer from repeated fault impact of a power grid; the requirements of 'selectivity' and 'rapidity' can be simultaneously considered; the automatic identification of the distribution network switch belongs to the section or the connection and the automatic input of the corresponding function can be realized; the self-adaptive distribution network can operate in a normal mode and an abnormal mode, and functions can be normally put into the operation in the normal mode and the abnormal mode; the integrated design meets different application occasions such as distribution network fault isolation, intelligent demarcation of users and the like; the device has simple overall design, high reliability, plug and play, easy maintenance, no power failure and easy popularization.
Drawings
The present disclosure will become more readily understood with reference to the accompanying drawings. As will be readily appreciated by those skilled in the art: the drawings are only for illustrating the technical scheme of the present invention and are not intended to limit the scope of the present invention. In the figure:
fig. 1 shows a block diagram of a distribution network protection device according to an embodiment of the invention.
Fig. 2 shows a flow chart of a method of protecting a distribution network according to an embodiment of the invention.
Fig. 3 shows a segmented circuit breaker monitoring/self-healing process flow diagram of the distribution network protection method of one embodiment of the present invention as shown in fig. 2.
Detailed Description
Figures 1-3 and the following description depict alternative embodiments of the invention to teach those skilled in the art how to make and reproduce the invention. In order to teach the technical solution of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations or alternatives derived from these embodiments that fall within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention. Thus, the invention is not limited to the following alternative embodiments, but only by the claims and their equivalents.
Fig. 1 shows a distribution network protection device according to an embodiment of the present invention, wherein the protection device comprises a circuit breaker 1, a double-sided voltage detection unit 2, a current detection unit 3, an on-off switching unit 4, a digital-to-analog conversion unit 5, a central processing unit 6, a controller 7, an input-output unit 8 and a communication unit 9, and the controller 7 comprises a switching-on control unit, wherein the circuit breaker 1 is connected with the double-sided voltage detection unit 2, the current detection unit 3, the on-off switching unit 4 and the controller 7, the double-sided voltage detection unit 2 and the current detection unit 3 are respectively connected with the digital-to-analog conversion unit 5, the digital-to-analog conversion unit 5 is connected with the central processing unit 6, the central processing unit 6 is connected with the on-off switching unit 4, the input-output unit 8 and the communication unit 9, the on-off switching unit 4 is connected with the controller 7, the double-sided voltage detection unit 2 is used for detecting respective phase voltages and zero sequence voltages on three lines of the circuit breaker 1, the current detection unit 3 is used for detecting respective phase currents and zero sequence currents on three lines passing through the circuit breaker 1, the on the three lines is used for detecting positions of the circuit breaker 1 and transmitting signals of the central processing unit 6 to the controller 7 to the switching-on the switching-off switching-on switching unit 6 is used for receiving signals for switching-off control of the communication after the switching-on and switching-off control unit 1 is used for controlling the switching-on and switching.
According to the distribution network protection device provided by the embodiment of the invention, the protection device comprises:
the double-sided voltage detection unit 2 detects voltages UA, UB, UC,3UO at both ends of the circuit breaker 1 and transmits the detection result to the central processing unit 6 through the digital-analog conversion part 5, the current detection unit 3 detects currents IA, IB, IC and transmits the detection result to the central processing unit 6 through the digital-analog conversion part 5; and
the central processor 6 performs the segment breaker 1 monitoring/self-healing process.
According to the distribution network protection device provided by the above embodiment of the present invention, the monitoring/self-healing process of the segment breaker 1 includes:
the double-sided voltage detection unit 2 detects voltages UA, UB, UC,3UO at both ends of the circuit breaker 1 and transmits the detection result to the central processing unit 6 through the digital-analog conversion part 5, and the current detection unit 3 detects currents IA, IB, IC,3IO and transmits the detection result to the central processing unit 6 through the digital-analog conversion part 5;
the central processing unit 6 judges whether single-phase earth fault occurs according to 3UO and 3I0 of the breaker 1, if yes, the central processing unit 6 controls the delay trip of the breaker 1 through the opening and closing unit 4 and the controller 7; if not, judging whether a three-phase symmetrical fault occurs according to the IA, IB and IC of the circuit breaker 1, and if so, controlling the circuit breaker 1 to trip in a delay mode by the CPU 6 through the switching-in switching-out unit 4 and the controller 7; if not, the central processing unit 6 judges whether two-phase asymmetric faults occur according to the IA, IB and IC of the circuit breaker 1, and if so, the central processing unit 6 controls the circuit breaker 1 to trip in a delay mode through the opening and closing unit 4 and the controller 7; if not, the central processing unit 6 judges whether the three-phase voltage loss condition is met or not and the fault current is generated according to UA, UB, UC,3UO,IA,IB,IC of the circuit breaker 1, and if yes, the central processing unit 6 controls the circuit breaker to trip in a delay mode through the opening and closing unit 4 and the controller 7; if not, the central processing unit 6 judges whether the three-phase voltage loss condition is met according to UA, UB, UC,3UO of the breaker 1;
the central processing unit 6 judges whether the three-phase voltage-losing conditions are met according to UA, UB, UC and 3UO of the circuit breaker 1, if yes, the central processing unit 6 judges whether the preset three-phase voltage-losing tripping delay time is reached, and if yes, the central processing unit 6 controls the circuit breaker to delay tripping through the opening-closing unit 4 and the controller 7; if not, the central processing unit 6 judges whether the fault residual voltage is detected, and if not, the central processing unit 6 judges whether the preset three-phase voltage-losing tripping delay time is reached again; if yes, the communication unit 9 sends a locking signal to a lower relay far away from the power end, then the central processing unit 6 judges whether the communication unit 9 receives the locking signal sent by an upper relay close to the power end, if yes, the device returns, if not, the central processing unit 6 judges whether the preset waiting time of the locking signal is reached, if yes, the circuit breaker 1 trips, the switching-on controller 7 discharges, and the input and output unit 8 outputs locking switching-on information; if not, the central processing unit 6 judges whether a locking signal sent by an upper relay close to the power end is received again;
the double-sided voltage detection unit 2 detects voltages UA, UB, UC,3UO at both ends of the circuit breaker 1 and transmits the detection result to the central processing unit 6 through the digital-analog conversion part 5;
the central processing unit 6 judges whether the circuit breaker 1 has pressure on one side, if yes, the central processing unit 6 judges whether the voltage is instantaneous residual voltage, if yes, the switching-on controller 7 discharges, and the input and output unit 8 outputs locking and switching-on information; if not, the central processing unit 6 controls the delay closing of the breaker 1 through the opening-in-opening-out unit 4 and the controller 7; the method comprises the steps of,
the breaker 1 judges whether the switch-on is in a fault state, if yes, the breaker 1 accelerates tripping, the switch-on controller 7 discharges, and the input-output unit 8 outputs the switch-on locking information.
According to the distribution network protection device provided in the above embodiment of the present invention, the cpu 6 determines whether the voltages UA, UB, UC on both sides of the circuit breaker 1 are equal, and if not, the input/output unit 8 reports an error.
According to the distribution network protection device provided by the embodiment of the invention, the distribution network protection device also starts the 'sequential quick action' and the 'weak feed protection' functions after two-phase asymmetric faults occur, the input output unit 8 is provided with a switch for controlling whether the 'sequential quick action' and the 'weak feed protection' functions are effective, whether the 'sequential quick action' and the 'weak feed protection' functions are started or not is set by opening/closing the switch, the 'sequential quick action' function is used for accelerating the isolation of a fault distribution network, the 'weak feed protection' function is used for enabling a fault point to be tripped instantaneously on the opposite side when a near-outlet fault of a distribution network line power supply side occurs, and the fault power supply side continuously senses the fault and simultaneously senses the change of electric quantity again so as to accelerate the tripping.
According to the distribution network protection device provided by the embodiment of the invention, the delay tripping of the circuit breaker comprises the step of presetting different delay times according to the processing speed of the communication unit, the installation position of the circuit breaker and the fault type, for example, the delay time can be set from 5S or longer according to the processing speed of the communication unit to the locking signal.
According to the distribution network protection device provided by the embodiment of the invention, the delayed closing of the circuit breaker comprises the step of presetting different delay time, such as 1-3 seconds or longer, according to factors such as the material of a power line, the arc extinguishing time, the user property and the like.
Fig. 2 shows a flowchart of a method for protecting a distribution network according to an embodiment of the present invention, wherein the protecting device controls the distribution network, including a plurality of steps:
step 100: detecting voltages UA, UB, UC,3UO and detecting currents IA, IB, IC at two ends of the circuit breaker;
step 101: charging; the method comprises the steps of,
step 102: and performing a segment breaker monitoring/self-healing process.
Fig. 3 shows a block circuit breaker monitoring/self-healing process flow diagram of the distribution network protection device and method of one embodiment of the present invention as shown in fig. 2, wherein the block circuit breaker monitoring/self-healing process 102 comprises a plurality of steps:
step 200: detecting voltages UA, UB, UC,3UO at two ends of the circuit breaker, and detecting currents IA, IB, IC,3IO;
step 201: judging whether single-phase earth fault occurs according to the circuit breakers 3UO and 3I0, if so, executing step 212; if not, go to step 202;
step 202: judging whether a three-phase symmetrical fault occurs according to the IA, IB and IC of the circuit breaker, if so, executing step 212; if not, go to step 203;
step 203: judging whether two-phase asymmetric faults occur according to the IA, IB and IC of the circuit breaker, if so, executing step 212; if not, go to step 204;
step 204: judging whether the three-phase voltage loss condition is met or not and the fault current is generated according to UA, UB, UC,3UO,IA,IB,IC of the circuit breaker, if yes, executing step 212; if not, go to step 205;
step 205: judging whether the three-phase voltage loss condition is met according to UA, UB, UC,3UO of the circuit breaker, if yes, executing step 206; if not, executing step 200;
step 206: judging whether the preset three-phase voltage-losing tripping delay time is reached, wherein the three-phase voltage-losing tripping delay time is 5 seconds or longer, if yes, executing step 212; if not, go to step 207;
step 207: judging whether the fault residual pressure is detected, if so, executing step 208; if not, go to step 206;
step 208: sending a locking signal to a lower relay far away from a power supply end;
step 209: judging whether a locking signal sent by an upper relay close to a power end is received, if not, executing step 210; if yes, go to step 100;
step 210: judging whether the preset blocking signal waiting time is reached, if so, executing step 211; if not, go to step 209, where the latching signal latency is shorter than the three-phase voltage-loss trip delay, for example, when the three-phase voltage-loss trip delay is 5 seconds, the latching signal latency is 3 seconds;
step 211: tripping and discharging the circuit breaker, outputting locking and closing information, and ending the processing;
step 212: delay tripping of the circuit breaker;
step 213: detecting voltages UA, UB, UC,3UO at two ends of the circuit breaker;
step 214: judging whether the circuit breaker is pressed on one side, if so, executing step 215; if not, go to step 213;
step 215: judging whether the voltage is a transient residual voltage, if so, executing step 219; if not, go to step 216;
step 216: the circuit breaker is switched on in a time-delay way;
step 217: judging whether the breaker is switched on in a fault state, if so, executing step 218; if not, go to step 100;
step 218: the circuit breaker accelerates tripping; and
step 219: discharging, outputting locking and closing information, and ending the processing.
According to the distribution network protection device provided by the embodiment of the invention, the distribution network protection device further comprises a sequential quick-action function and a weak feed protection function which are started after two-phase asymmetric faults occur, whether the sequential quick-action function and the weak feed protection function are effective or not is set through an input-output unit, the sequential quick-action function is used for accelerating isolation of a fault distribution network, the weak feed protection function is used for tripping instantaneously on the opposite sides of a fault point when a near-outlet fault occurs on the power supply side of a distribution network circuit, and the fault power supply side continuously senses the fault and simultaneously senses the change of electric quantity again to accelerate tripping.
According to the distribution network protection device provided by the embodiment of the invention, the delay tripping of the circuit breaker comprises the step of presetting different delay times according to the processing speed of the communication unit, the installation position of the circuit breaker and the fault type, for example, the delay time can be set from 5S or longer according to the processing speed of the communication unit to the locking signal.
According to the distribution network protection device provided by the embodiment of the invention, the delayed closing of the circuit breaker comprises the step of presetting different delay time, such as 1-3 seconds or longer, according to factors such as the material of a power line, the arc extinguishing time, the user property and the like.
The distribution network protection device has the advantages that: the method does not depend on wired communication, does not depend on protection and reclosing cooperation of a 10kV line outlet of a transformer substation, does not depend on secondary superposition, does not depend on switching cooperation of a plurality of circuit breakers, and does not suffer from repeated fault impact of a power grid; the requirements of 'selectivity' and 'rapidity' can be simultaneously considered; the automatic identification of the distribution network switch belongs to the section or the connection and the automatic input of the corresponding function can be realized; the self-adaptive distribution network can operate in a normal mode and an abnormal mode, and functions can be normally put into the operation in the normal mode and the abnormal mode; the integrated design meets different application occasions such as distribution network fault isolation, intelligent demarcation of users and the like; the device has simple overall design, high reliability, plug and play, easy maintenance, no power failure and easy popularization.
It will of course be realised that while the foregoing has been given by way of illustrative example of this invention, such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is herein set forth. Thus, although the invention has been described with reference to preferred embodiments, it is not intended to be limited thereby to the novel apparatus, but, on the contrary, it is intended to cover various modifications and equivalent arrangements included within the broad scope of the foregoing disclosure, and the appended claims.
Claims (9)
1. The protection device is characterized by comprising a circuit breaker, a double-side voltage detection unit, a current detection unit, an opening/closing unit, a digital-to-analog conversion part, a central processing unit, a controller, an input/output unit and a communication unit, wherein the controller comprises a switching-on control part, the circuit breaker is connected with the double-side voltage detection unit, the current detection unit, the opening/closing unit and the controller, the double-side voltage detection unit and the current detection unit are respectively connected with the digital-to-analog conversion part, the digital-to-analog conversion part is connected with the central processing unit, the central processing unit is connected with the opening/closing unit, the input/output unit and the communication unit, the opening/closing unit is connected with the controller, the double-side voltage detection unit is used for detecting respective phase voltages and respective zero sequence voltages of two ends of the circuit breaker on three wires, the current detection unit is used for detecting respective phase currents and zero sequence currents on the three wires passing through the circuit breaker, the opening/closing control part is used for detecting position contact points of the circuit breaker and transmitting signals of the central processing unit to the controller, and the communication unit is used for sending and receiving locking signals after charging;
the protection device includes: the double-sided voltage detecting unit detects a voltage across the circuit breaker,
UA, UB, UC,3UO and transmits the detection result to the central processing unit through the digital-to-analog conversion component, the current detection unit detects the currents IA, IB, IC and transmits the detection result to the central processing unit through the digital-to-analog conversion component; the central processing unit executes the monitoring/self-healing processing of the sectional circuit breaker;
the segmented circuit breaker monitoring/self-healing process includes:
the double-side voltage detection unit detects voltages UA, UB, UC,3UO at two ends of the circuit breaker and transmits detection results to the central processing unit through the digital-to-analog conversion component, and the current detection unit detects currents IA, IB, IC,3IO and transmits detection results to the central processing unit through the digital-to-analog conversion component;
judging whether a single-phase earth fault occurs by the central processing unit according to 3UO and 3I0 of the circuit breaker, and if so, controlling the circuit breaker to trip in a delay manner through the switching-in switching-out unit and the controller by the central processing unit; if not, judging whether a three-phase symmetrical fault occurs according to the IA, IB and IC of the circuit breaker, and if so, controlling the circuit breaker to trip in a delay way by the CPU through the on-off unit and the controller; if not, the central processing unit judges whether two-phase asymmetric faults occur according to the IA, IB and IC of the circuit breaker, and if so, the central processing unit controls the circuit breaker to trip in a delay way through the opening and closing unit and the controller; if not, the central processing unit judges whether the three-phase voltage loss condition is met or not and the fault current is generated according to UA, UB, UC,3UO,IA, IB, IC of the circuit breaker, and if so, the central processing unit controls the circuit breaker to trip in a delay mode through the opening and closing unit and the controller; if not, the central processing unit judges whether the three-phase voltage loss condition is met according to UA, UB, UC and 3UO of the circuit breaker;
the central processing unit judges whether the three-phase voltage-losing conditions are met according to UA, UB, UC and 3UO of the circuit breaker, if so, the central processing unit judges whether the preset three-phase voltage-losing tripping delay time is reached, and if so, the central processing unit controls the circuit breaker to delay tripping through the opening-closing unit and the controller; if not, the central processing unit judges whether the fault residual voltage is detected, if not, the central processing unit judges whether the preset three-phase voltage-loss tripping delay time is reached again; if yes, the communication unit sends a blocking signal to a lower relay far away from the power end, then the central processing unit judges whether the communication unit receives the blocking signal sent by an upper relay close to the power end, if yes, the device returns, if not, the central processing unit judges whether the preset blocking signal waiting time is reached, if yes, the circuit breaker trips, the switching-on controller discharges, and the input and output unit outputs blocking switching-on information; if not, the central processing unit judges whether a locking signal sent by an upper relay close to the power end is received again;
the double-side voltage detection unit detects voltages UA, UB, UC,3UO at two ends of the circuit breaker and transmits detection results to the central processing unit through the digital-to-analog conversion component;
the central processing unit judges whether the circuit breaker has voltage on one side, if so, the central processing unit judges whether the voltage is instantaneous residual voltage, if so, the switching-on controller discharges, and the input and output unit outputs locking switching-on information; if not, the central processing unit controls the delay closing of the circuit breaker through the opening-in-opening-out unit and the controller; and judging whether the circuit breaker is switched on in a fault state, if so, accelerating tripping of the circuit breaker, discharging the switching-on controller, and outputting locking and switching-on information by the input and output unit.
2. The distribution network protection device according to claim 1, further comprising a step of starting a 'sequential snap-action' and a 'weak feed protection' function after occurrence of a two-phase asymmetric fault, wherein whether the 'sequential snap-action' and the 'weak feed protection' functions are effective or not is set by an input-output unit, the 'sequential snap-action' function is used for accelerating isolation of the fault distribution network, the 'weak feed protection' function is used for instantaneous tripping at a fault point side when a near-outlet fault of a power supply side of a distribution network line occurs, and the fault power supply side continuously senses the fault and simultaneously senses the change of electric quantity again to accelerate tripping.
3. The distribution network protection device of claim 2, wherein the circuit breaker delay tripping includes presetting different delay times according to different processing speeds of the communication units, installation positions of the circuit breakers, and fault types.
4. A distribution network protection device according to claim 3, wherein the delayed closing of the circuit breaker comprises preset different delay times according to different line materials, arc extinguishing times and user properties.
5. A distribution network protection method of a distribution network protection device according to claim 4, characterized in that the protection method comprises the steps of:
step 1: detecting voltages UA, UB, UC,3UO and detecting currents IA, IB, IC at two ends of the circuit breaker; and
step 2: and performing a segment breaker monitoring/self-healing process.
6. The distribution network protection method of claim 5, wherein the segment breaker monitoring/self-healing process comprises a plurality of steps:
step 3: detecting voltages UA, UB, UC,3UO at two ends of the circuit breaker, and detecting currents IA, IB, IC,3IO;
step 4: judging whether single-phase earth faults occur according to 3UO and 3I0 of the circuit breaker, if so, executing the step 8; if not, judging whether a three-phase symmetrical fault occurs according to the IA and IB of the circuit breaker, and if so, executing the step 8; if not, judging whether two-phase asymmetric faults occur according to the IA and IB of the circuit breaker, and if so, executing the step 8; if not, judging whether the three-phase voltage loss condition is met or not and the fault current is generated according to UA, UB, UC,3UO,IA, IB, IC of the circuit breaker, if so, executing the step 8; if not, judging whether the three-phase voltage loss condition is met according to UA, UB, UC,3UO of the circuit breaker, and if not, executing the step 3; if yes, executing the step 5;
step 5: judging whether the preset three-phase voltage-loss tripping delay time is reached, if so, executing the step 8; if not, judging whether the fault residual pressure is detected, and if not, executing the step 5; if yes, a locking signal is sent to a lower relay far away from a power end, and then, the step 6 is executed;
step 6: judging whether a locking signal sent by an upper relay close to a power end is received or not, if not, executing the step 7; if yes, executing the step 1;
step 7: judging that the preset blocking signal waiting time is reached, if yes, tripping the circuit breaker, discharging, and outputting blocking and closing information; if not, executing the step 6 again;
step 8: delay tripping of the circuit breaker;
step 9: detecting voltages UA, UB, UC,3UO at two ends of the circuit breaker;
step 10: judging whether the circuit breaker is pressed on one side, if so, executing the step 11; if not, executing the step 8;
step 11: judging whether the voltage is instantaneous residual voltage, if so, discharging and outputting locking and closing information; if not, the circuit breaker is switched on in a delay way, and then the step 12 is executed; the method comprises the steps of,
step 12: judging whether the breaker is switched on in a fault state, if so, accelerating tripping, discharging and outputting locking and switching-on information; if not, executing the step 1.
7. The distribution network protection method according to claim 6, further comprising starting a "sequential snap-action" and a "weak feed protection" function after occurrence of a two-phase asymmetric fault, wherein whether the "sequential snap-action" and the "weak feed protection" functions are effective or not is set by the input-output unit, the "sequential snap-action" function is used for accelerating isolation of the faulty distribution network, the "weak feed protection" function is used for instantaneous tripping of a fault point opposite sides when a near-outlet fault of a power side of a distribution network line occurs, and the fault power side continuously senses the fault and simultaneously senses the change of electric quantity again to accelerate tripping.
8. The distribution network protection method of claim 7, wherein the time-lapse tripping of the circuit breaker includes presetting different time-lapse times according to the processing speed of the communication unit, the installation position of the circuit breaker, and the type of the fault.
9. The method of claim 8, wherein the time-delay switching-on of the circuit breaker comprises presetting different time-delay times according to different line materials, arc extinguishing times and user properties.
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| CN110571771B (en) * | 2019-10-17 | 2021-06-15 | 广西电网有限责任公司南宁供电局 | Novel self-adaptive power distribution automation fault judgment isolation mode method |
| CN114498573A (en) * | 2020-10-26 | 2022-05-13 | 南京易锐普电力科技有限公司 | Power distribution network protection device and method |
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| CN102904228A (en) * | 2012-10-17 | 2013-01-30 | 南京因泰莱配电自动化设备有限公司 | Protection method and protection device of power distribution network |
| CN205647023U (en) * | 2016-02-15 | 2016-10-12 | 国网山东省电力公司章丘市供电公司 | Supply power distribution monitoring system |
| WO2017166735A1 (en) * | 2016-03-31 | 2017-10-05 | 国电南瑞科技股份有限公司 | Power-grid self-healing system and self-healing logic thereof in 110kv chain power-supply mode |
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| CN102904228A (en) * | 2012-10-17 | 2013-01-30 | 南京因泰莱配电自动化设备有限公司 | Protection method and protection device of power distribution network |
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| WO2017166735A1 (en) * | 2016-03-31 | 2017-10-05 | 国电南瑞科技股份有限公司 | Power-grid self-healing system and self-healing logic thereof in 110kv chain power-supply mode |
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