Disclosure of Invention
The invention provides a method for generating the topology of a low-voltage distribution network with faults according to fault information, which aims to effectively position and isolate the faults when the faults occur.
In order to achieve the purpose, the invention adopts the following technical scheme: a method of fault location in a power distribution network in which circuit breakers are installed in a first stage integrated distribution box adjacent a power source and in cable breakout boxes elsewhere on the distribution network.
The communication control terminals are arranged in the distribution box and the branch boxes, the communication control terminals acquire states of the circuit breakers in the distribution box or the branch boxes, the communication control terminals are in communication connection with the upper computer, and the states of the circuit breakers are uploaded to the upper computer through the communication control terminals.
The functions of the circuit breaker input include:
a-1, overcurrent delay tripping function: after detecting the current exceeds the over-current set point, the trip is carried out after a time delay T1.
B-1, overcurrent and voltage loss tripping function: the circuit breaker detects the circuit and overflows the trouble under having pressure and closing the position state, and the circuit does not have the current after not having the pressure, sends the tripping operation signal of shutting to other circuit breakers in this branch case, and the circuit breaker tripping operation after time delay T4.
B-2, a delay switching-on function is provided at the power supply side: when the breaker is in a position-separating state, the power supply side is changed from no voltage to voltage, and the breaker is switched on after short time delay T5; and if no overcurrent fault is detected within the time T3 after the switch-on, the acceleration function after the switch-on is locked.
B-3, accelerating function after closing: the breaker is positioned and has no current, and overcurrent fault is detected in T3 after the breaker is closed without delay tripping.
B-4, a power supply side voltage loss tripping function: after the voltage of the power supply side is lost, if a locking tripping signal sent by other circuit breakers in the branch box is not received within the time T4, the circuit breaker trips; if a blocking tripping signal sent by other circuit breakers in the branch box is received within the time T4, the circuit breaker does not operate.
B-5, residual voltage sensing function: when the circuit breaker is positioned, voltage larger than the fixed value of residual voltage appears on the power supply side, and the residual voltage signal with the duration time smaller than T5 is sent out.
Preferably, the circuit breaker in the distribution box drops into function A-1 and the circuit breaker in the branch box drops into functions B-1 to B-5.
Based on the configuration, the communication control terminal transmits the action of the breaker and the detected fault information to the upper computer to realize fault positioning, and the fault positioning method comprises the following steps:
step 1-1, when an overcurrent fault occurs on a power distribution network, a breaker through which a fault current flows between a power supply point and a fault point detects the overcurrent fault.
And step 1-2, the breaker with the overcurrent fault detected in the distribution box trips according to the A-1 function.
And step 1-3, the breaker with the overcurrent fault detected in the branch box trips according to the function B-1.
Step 1-4, detecting a breaker with voltage loss at the power supply side, and tripping according to a B-4 function if the breaker with overcurrent fault is not detected in the branch box; if the circuit breaker which detects the overcurrent fault exists in the branch box, the circuit breaker does not act because the step 1-3 receives the locking tripping signal.
And (1) controlling the circuit breaker tripped in the distribution box by the upper computer, and switching on after T2 tripping time.
Step 1-6, the power supply side of each breaker in the next stage branch box of the closing breaker has pressure,
the breaker tripping according to the function B-1 in the branch box is switched on according to the function B-2;
the breaker tripping according to the function B-4 in the branch box is switched on according to the function B-2;
and (5) repeating the steps 1-6 until the fault point is higher than the first-stage branch box.
And 1-7, in a primary branch box at a fault point, tripping a breaker according to the function B-1, switching on the breaker according to the step 1-6, and tripping according to the function B-3 without delay.
And 1-8, detecting the line residual voltage by the next-stage circuit breaker of the circuit breaker according to the function B-5 because the circuit breaker in the step 1-7 is switched on to have a fault.
Based on the above process, the automatic identification of the topology is completed, which includes the following steps.
And 2-1, storing the power supply and the comprehensive distribution box as an initial topological graph by the upper computer.
And 2-2, adding the circuit breaker which detects the overcurrent fault in the branch box into the topological graph after receiving the information sent in the step 1-1, wherein the circuit breaker has no connection relation in the topological graph.
And 2-3, adding a circuit breaker with a tripping action in the topology according to the received information sent from the steps 1-2 to 1-4.
And 2-4, after the steps 1-5, obtaining the connection relation of the breakers subjected to voltage-loss tripping after the overcurrent fault is detected in the step 2-3 according to the closing time sequence of the breakers subjected to the overcurrent fault in the step 1-6, namely the upstream fault line topology of the fault point.
And 2-5, determining the circuit breaker which detects the residual voltage as a lower-level circuit breaker of the fault point according to the received residual voltage sensing information sent in the steps 1-8.
According to the invention, the circuit breakers at different positions are put into different functions, when overcurrent faults occur, the circuit breakers respectively have different actions according to different putting-in functions, and the states and actions of the circuit breakers are uploaded. The circuit breaker judges a fault point according to self logic, isolates a fault area, and obtains the topological structure of a fault line through fault information and actions of the circuit breaker after closing.
Has the advantages that: by adopting the invention, the judgment and isolation of the fault point do not depend on the known distribution network topology, and the invention is especially suitable for the condition that the network topology changes frequently. When the fault point is judged, the network topology structure related to the fault path can be obtained, and conditions are provided for fault maintenance and fault analysis.
Detailed Description
The following embodiments are implemented in a low voltage distribution network.
Time setting: the T1-T5 are set according to specific requirements, and the setting range of each time (the unit is s, second):
T1=0.1-0.4s,T2=10-20s,T3=3-6s,T4=2-4s,T5=5-10s。
the invention is further described below with reference to the accompanying drawings.
Referring to fig. 1 and 2, a low-voltage comprehensive distribution box is connected to the nearest power supply side, and the other cable branch boxes are connected to the nearest power supply side.
In this application, the block terminal indicates the first order low pressure that is close to the power side and synthesizes the block terminal, and the feeder pillar indicates the cable feeder pillar on other positions.
Description of the configuration: 1-1 to 1-4 are circuit breakers disposed inside the integrated distribution box, 2-1 to 2-4, 3-1 to 3-4, 4-1 to 4-4, 5-1 to 5-4, 6-1 to 6-4, and 7-1 to 7-4 are circuit breakers disposed inside the cable branch box, and the circuit breakers can cut off fault currents.
Each of the integrated distribution box and the cable branch box is provided with a communication control terminal 1.
The circuit breaker is provided with an intelligent terminal, and the terminal collects three-phase current flowing through the circuit breaker and three-phase voltage on the power supply side, detects the state of the circuit breaker, controls the action of the circuit breaker and completes the control logic of the circuit breaker.
In the invention, the intelligent terminal is realized by adopting two configuration modes:
1. a circuit breaker control terminal (not shown in the figure) collects three-phase current flowing through the circuit breaker and three-phase voltage on the power supply side, detects the state of a line, controls the action of the circuit breaker and completes the control logic of the circuit breaker; the circuit breaker control terminal communicates in some way, such as bus, ethernet, etc., and transmits the collected or generated signal to the communication control terminal. In this way, control and communication is accomplished through two functional modules.
2. The communication control terminal collects three-phase current flowing through the circuit breaker and three-phase voltage on the power supply side, detects the state of a line, controls the action of the circuit breaker and completes the control logic of the circuit breaker in the distribution box or the branch box. In this way, the communication control terminal controls all the circuit breakers in the distribution box or the branch box, and the control and the communication are completed by the communication control terminal.
The communication control terminal 1 transmits the acquired or generated signal to an upper computer in the modes of LORA, optical cable, power line carrier and the like.
The circuit breaker control terminal (not marked in the figure) or the communication control terminal 1 and the circuit breaker form an intelligent circuit breaker together.
The intelligent circuit breaker collects three-phase current flowing through the circuit breaker and three-phase voltage on a power supply side, has the functions of detecting faults, opening and closing states, line voltage loss, acceleration after closing, delayed closing on the power supply side, residual voltage sensing and the like, and transmits signals to an upper computer through a communication control terminal 1 in the modes of carrier waves, LORA, wireless public networks, optical fibers and the like.
Hereinafter, "circuit breaker" means "smart circuit breaker".
In order to save cost, 1-0, 2-0, 3-0, 4-0, 5-0, 6-0 and 7-0 do not use a breaker, and can be a switch which has no electric operating mechanism and only has a manual switching-on and switching-off function.
The upper computer is a cloud master station as shown in fig. 1, or a fog terminal with edge computing capability as shown in fig. 2.
In fig. 2, a fog terminal with edge computing capability is provided in a low voltage integrated power distribution box.
The fog terminal with edge computing capability is local intelligent equipment, processes data under the transformer and completes fault positioning, fault isolation and automatic topology identification.
And the time synchronization module of each communication control terminal and the time synchronization system of the upper computer ensure the time consistency of the whole system.
A backup power supply is arranged in the comprehensive distribution box and the cable branch box, so that fault information and state can be uploaded in a short time after a fault power failure, and a circuit breaker can be disconnected after the power failure.
The function of the circuit breaker input.
The function of the circuit breaker is different according to different positions. In the invention, the circuit breakers located in the comprehensive distribution box and the cable branch box are put into different functions.
Synthesize the function that the circuit breaker drops into in the block terminal and include:
a-1, overcurrent delay tripping function: after detecting the current exceeds the over-current set point, the trip is carried out after a time delay T1.
The over-current set value is determined according to the field load. If the field load is 10A maximum, the over-current set point may be set to 12A.
The functions of the breaker in the branch box include:
b-1, overcurrent and voltage loss tripping function: the circuit breaker detects the circuit and overflows the trouble under having pressure and closing the position state, and the circuit does not have the current after not having the pressure, sends the tripping operation signal of shutting to other circuit breakers in this branch case, and the circuit breaker tripping operation after time delay T4.
B-2, a delay switching-on function is provided at the power supply side: when the breaker is in a position-separating state, the power supply side is changed from no voltage to voltage, and the breaker is switched on after short time delay T5; and if no overcurrent fault is detected within the time T3 after the switch-on, the acceleration function after the switch-on is locked.
B-3, accelerating function after closing: the breaker is positioned and has no current, and overcurrent fault is detected in T3 after the breaker is closed without delay tripping.
B-4, a power supply side voltage loss tripping function: after the voltage of the power supply side is lost, if a locking tripping signal sent by other circuit breakers in the branch box is not received within the time T4, the circuit breaker trips; if a blocking tripping signal sent by other circuit breakers in the branch box is received within the time T4, the circuit breaker does not operate.
B-5, residual voltage sensing function: when the circuit breaker is positioned, voltage larger than the fixed value of residual voltage appears on the power supply side, and the residual voltage signal with the duration time smaller than T5 is sent out.
In function B-5, the residual voltage fixed value is 30% of the rated phase voltage. If the rated phase voltage of the low-voltage distribution network is 220V, the residual voltage is 66V.
In this embodiment, the time for putting into function is as follows:
T1=0.2s,T2=15s,T3=5s,T4=3s,T5=7s。
the function of the circuit breaker can be realized by directly controlling the circuit breaker by the upper computer according to the received information, which needs reliable communication to guarantee; or locally, through a circuit breaker control terminal or a communication control terminal.
And (4) fault isolation.
According to the functional input, when overcurrent faults are detected on the low-voltage distribution line, fault point positioning and isolation are completed through action coordination among the circuit breakers.
Embodiment referring to fig. 3, the fault point is at the back end K of the circuit breaker 4-3.
Step 1-1, as shown in fig. 3, when a short-circuit fault occurs at the point K shown in the figure, the circuit breakers 1-1, 2-3 and 4-3 between the power supply point and the fault point can detect the overcurrent fault and memorize the fault information.
And step 1-2, the circuit breaker 1-1 in the distribution box trips due to overcurrent delay, and trips after T1 after overcurrent fault.
And step 1-3, tripping the circuit breakers 2-3 and 4-3 in the branch box according to the function B-1.
Step 1-4, the power supply side of the circuit breaker in the cable branch boxes 1, 3, 4, 5 and 6 loses voltage due to the tripping of the circuit breaker 1-1.
In the branch boxes 4, 5, 6, since no circuit breaker detects an overcurrent fault, the circuit breakers 5-1 to 5-4 are tripped, the circuit breakers 6-1 to 6-4 are tripped, and the circuit breakers 7-1 to 7-4 are tripped according to the function B-4.
In the branch box 1, the circuit breakers 2-3 send the locking tripping signal to the circuit breakers 2-1, 2-2 and 2-4 according to the function B-1, and the circuit breakers 2-1, 2-2 and 2-4 do not act according to the function B-4.
Similarly, the breakers 4-1, 4-2, 4-4 are not operated in the branch box 3.
The above steps complete the trip action after the fault.
The following steps complete the location and isolation of the fault point.
And 1-5, the upper computer knows that the breaker 1-1 in the distribution box trips due to overcurrent faults, and controls the breaker 1-1 to be switched on after the breaker trips for T2 time.
In the branch box 1: and step 1-6, switching on the circuit breaker 1-1, wherein the power supply side of the circuit breaker in the branch box 1 has pressure. The breaker 2-3 trips in the step 1-3, so that the breaker is switched on according to the function B-2, and the other breakers 2-1, 2-2 and 2-4 are switched off and do not act, so that power supply is recovered.
In the branch box 5: and (1) step (6), the power supply side of the circuit breaker has voltage, the circuit breakers 6-1 to 6-4 are switched on, and power supply is recovered.
In the branch box 3: and 1-6, after the circuit breaker 2-3 is switched on, the power supply side of the circuit breaker in the branch box 3 has pressure. The breaker 4-3 trips in the step 1-3, the breaker is switched on according to the function B-2, and the other breakers 4-1, 4-2 and 4-4 are switched off and do not act, so that power supply is recovered.
In the branch box 6: and (1) 6, the power supply side of the circuit breaker has voltage, the circuit breakers 7-1 to 7-4 are switched on, and power supply is recovered.
After the circuit breaker 4-3 is switched on in the step 1-7, the circuit breaker 4-3 is switched on to a fault due to the fact that the circuit breaker 4-3 is close to a fault point, and the circuit breaker 4-3 does not have time delay tripping.
Step 1-8, tripping the circuit breakers 5-1, 5-2, 5-3 and 5-4 in the branch box 4 in the step 1-4 to be in a position division state; because the circuit breaker 4-3 detects a fault within the time T3 after being switched on, the circuit breaker accelerates tripping according to the function B-3, and the circuit breakers 5-1, 5-2, 5-3 and 5-4 can detect residual voltage information according to the function B-5 and send residual voltage sensing information.
Since the circuit breaker 4-3 is switched on and then the fault is detected to be tripped without delay within the time T3, the fault current returns before the circuit breaker 1-1 is delayed by the time T1, and the circuit breaker 1-1 does not trip according to the function A-1.
Because the circuit breaker 4-3 is engaged in the fault, although the circuit breaker 2-3 detects the overcurrent information, the circuit breaker can not trip because of no voltage loss, and the overcurrent memory is reset after short time delay.
The circuit breaker 4-3 trips and the circuit breakers 5-1 to 5-4 trip at step 1-4 loss of voltage, isolating the fault zone.
Through the steps, the fault point is isolated from the low-voltage distribution network, and meanwhile, power supply is recovered to the non-fault area.
And automatically identifying the topology.
And the upper computer automatically completes topology identification according to the information received in the fault isolation process.
Embodiment referring to fig. 3, the fault point is at the back end K of the circuit breaker 4-3.
And 2-1, due to the variability of the net rack and the complexity of the power distribution network, the upper computer (a cloud master station or a fog terminal) cannot obtain the full-network topology. In the invention, the upper computer does not store all topological structures of the net rack. The low-voltage comprehensive distribution box is closest to the power supply, and basically has no connection change, so that the upper computer only stores the low-voltage comprehensive distribution box behind the power supply, as shown in fig. 4.
Step 2-2 and step 1-1, uploading information to all breakers which detect overcurrent faults, namely the breakers 1-1, 2-3 and 4-3; after receiving the information sent in the step 1-1, the upper computer adds the circuit breakers 2-3 and 4-3 which detect the overcurrent faults in the branch box into the topological graph, and because the faults basically occur at the same time, the upper and lower level relations of the circuit breakers cannot be obtained, and the circuit breakers have no connection relation in the topological graph, as shown in fig. 5.
Step 2-3, steps 1-2 to 1-4, the circuit breakers 5-1 to 5-4 are tripped, the circuit breakers 6-1 to 6-4 are tripped, the circuit breakers 7-1 to 7-4 are tripped, and the circuit breakers of the tripping action are added in the topology. Also, the relationship of the upper and lower stages of the circuit breaker cannot be determined at this time, as shown in fig. 6.
In the figure, the circuit breakers 6-1 to 6-4, 7-1 to 7-4 are not indicated, for reasons explained herein below.
Step 2-4, after step 1-5, switching on the circuit breaker 1-1, in step 1-6, switching on after short delay of voltage on the power supply side of the circuit breaker 2-3, can distinguish the circuit breaker 2-3 at the subordinate of the circuit breaker 1-1; the circuit breakers 6-1 to 6-4 are switched on, but the circuit breakers 6-1 to 6-4 are not judged to be positioned at the lower level of the circuit breaker in the branch box 1, and the upper computer cannot identify the network topology, so the circuit breakers 6-1 to 6-4 are not added in the topology map, and the topology is updated as shown in fig. 7.
At the next time after the circuit breaker 2-3 is switched on, in the step 1-6, the circuit breaker 4-3 is switched on after short delay under the pressure at the power supply side, and the upper computer can distinguish that the circuit breaker 4-3 is at the lower stage of the circuit breaker 2-3; the circuit breakers 7-1 to 7-4 are switched on, but the circuit breakers 7-1 to 7-4 are not judged to be positioned at the lower level of the circuit breaker in the branch box 3, and the upper computer cannot identify the network topology, so the circuit breakers 7-1 to 7-4 are not added in the topology map, and the topology is updated as shown in fig. 8.
Step 2-5, because the circuit breaker 4-3 detects a fault within the time of T3 after being switched on, in step 1-8, the circuit breakers 5-1 to 5-4 detect residual voltage, and according to residual voltage sensing information, the topology is updated as shown in FIG. 9.
And the upper computer automatically generates all breaker topological relations related to the fault finally through continuously updating the breaker topological relations related to the fault according to the overcurrent fault information, the tripping action caused by the fault and the closing information in the fault locating process.
The topological relation of the circuit breakers in the branch box is determined, for example, in the branch box 1, the topological relation of the circuit breakers 2-1 to 2-4 is bound with the branch box 1, and relevant information can be obtained from asset coding information to obtain information of one circuit breaker, so that the information of the whole branch box can be obtained.
And 2-6, storing the topological relation of each branch box by a communication control terminal in each branch box, uploading the topological relation to an upper computer through communication, and perfecting the network topology of the fault line by the upper computer according to configuration information.
Finally, the topology is updated as in fig. 10.
According to the topological relation, the fault point can be positioned, and in the embodiment, the point K is arranged in the middle part of the branch box 3 and the branch box 4.
According to the identified topological structure, fault analysis and positioning are achieved, fault points are located, specific positions of the fault points are sent to rush repair personnel according to GPS position information, and rapid rush repair and power restoration are achieved.
After the fault processing is completed, the cloud master station automatically generates a fault summary report which contains messages of fault line topology, fault analysis, fault processing, fault summary, fault prevention and the like.
The incoming switches 1-0, 2-0, 3-0, 4-0, 5-0, 6-0, 7-0 do not participate in the logic control action, and the above diagram is kept in the topological diagram for the sake of completeness.
By isolating a fault point, the topology of the faulty branch line can be obtained. With the advance of time, fault points in the low-voltage power distribution network are increased continuously, the topology stored by the upper computer can be improved through continuous iteration, and the overall topology of the whole low-voltage power distribution network is obtained finally.
In fig. 3, if a fault occurs behind the circuit breaker 4-2, the topology of the branch box 3, 6 can be obtained.
If a fault occurs behind the circuit breaker 2-1, the topology of the circuit breaker 1-1, the branch box 5 can be obtained.
If a fault occurs behind the circuit breaker 3-4, the topology of the circuit breaker 1-4, the branch box 2 and the next stage can be obtained.
By repeating the above process, the topology of the whole low-voltage distribution network of fig. 1 or fig. 2 can be obtained.
Although the application object in the above embodiments is a low voltage distribution network, the method of the present invention is also applicable to medium and high voltage distribution networks.