Power-off-free maintenance system and method for distribution network

Abstract

A distribution network uninterruptible power maintenance system comprises a 10 kV PT cabinet, a 10 kV switch cabinet and a 10 kV transformer platform which are connected in sequence, the 10 kV transformer platform is connected with a distribution network maintenance power flow control box and then connected to a user, the distribution network uninterruptible power maintenance system further comprises an electric pickup truck used for supplying power, the electric pickup truck is connected with the distribution network maintenance power flow control box, the 10 kV PT cabinet is connected with a transmitting end of a synchronous detector, and the synchronous detector is connected with a receiving end of the synchronous detector. The synchronous detector transmitting end is in wireless connection with the synchronous detector receiving end, and the synchronous detector receiving end is connected with the electric pickup truck; the electric pickup truck is provided with a combined battery. The technical problem to be solved by the invention is to provide the non-power-cut maintenance system and method for the distribution network, so that power supply for users can be maintained while line power-cut maintenance is performed, and a novel maintenance mode is realized.

Description

Technical Field

[0001] The invention relates to the technical field of distribution network maintenance, and in particular to a distribution network non-stop maintenance system and method. Background Art

[0002] Power supply reliability is an important criterion for measuring the continuous power supply capacity of the power supply system. Among them, the reliability of distribution network power supply is particularly critical. State Grid Corporation of China has long regarded the average power outage time and number of power outages of distribution network users as key work indicators. However, due to the cost of power system construction, the terminal stations in remote areas mostly use single-line power supply, resulting in low power supply reliability. Once a single-circuit line fails or the equipment needs to be shut down for regular inspection, the power supply of the terminal residents will be restricted, which not only affects people's livelihood, but also has a negative impact on the power supply indicators of the power company.

[0003] To address this problem, maintenance personnel often use diesel generators as temporary power sources, but this method has many shortcomings: first, diesel generators do not have the function of synchronous grid connection. Each connection and removal requires the user to shut down the power first, resulting in users experiencing two power outages during the maintenance of the substation; second, due to the cumbersome safety operation requirements and work ticket process, coupled with the time it takes to connect to the diesel generator, the process of switching from distribution network power supply to diesel generator power supply is relatively long; finally, with the increase in user electrical appliances and loads, small diesel generators can no longer meet the demand, and high-power diesel generators are difficult to use in practice due to their large size, heavy weight, inconvenient transportation, and the lack of large lifting equipment in the power supply station. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a distribution network non-stop maintenance system and method, which can maintain power supply to users while the line is shut down for maintenance, thereby realizing a new maintenance method.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a distribution network non-stop maintenance system, including a 10kVPT cabinet, a 10kV switch cabinet and a 10kV transformer connected in sequence, the 10kV transformer is connected to the distribution network maintenance flow control box and then connected to the user, and also includes an electric pickup truck for power supply, the electric pickup truck is connected to the distribution network maintenance flow control box, the 10kVPT cabinet is connected to the synchronous detector transmitter, the synchronous detector transmitter is wirelessly connected to the synchronous detector receiver, and the synchronous detector receiver is connected to the electric pickup truck; the electric pickup truck is equipped with a combined battery.

[0006] Preferably, the combined battery and the on-board battery of the electric pickup truck are both connected to a power output box, and the combined battery and the power output box are arranged in the rear bucket of the electric pickup truck.

[0007] Preferably, the combined battery is connected to the AC / DC mixer, the vehicle-mounted battery is connected to the AC / DC mixer via a vehicle-mounted inverter, the AC / DC mixer is connected to a power output box, and the AC / DC mixer also collects the three-phase AC voltage signal transmitted from the receiving end of the synchronization detector.

[0008] Preferably, the AC / DC mixer includes a DC / AC power unit and a control unit. The combined battery and the vehicle battery are connected to the DC / AC power unit through a DC bus. The control unit receives a three-phase AC voltage signal and controls the triggering of the DC / AC power unit, thereby outputting 380V three-phase AC power.

[0009] Preferably, the distribution network maintenance flow control box includes a first terminal for connecting to the distribution network and a second terminal for connecting to the user, and two backup power supply branches are connected between the first terminal and the second terminal, specifically including a third terminal and a fourth terminal, and the third terminal and the fourth terminal are respectively connected to the power output boxes on the two electric pickup trucks.

[0010] Preferably, a circuit breaker, a first AC contactor and a second AC contactor are respectively provided between the first terminal, the third terminal and the fourth terminal and the second terminal, and also includes a control circuit for controlling the circuit breaker, the first AC contactor and the second AC contactor.

[0011] Preferably, it also includes a lifting trolley for transporting the assembled battery, the assembled battery is placed on the top of the lifting trolley, and the lifting trolley lifts the assembled battery to be flush with the rear bucket of the electric pickup truck.

[0012] A method for using a distribution network non-stop maintenance system, When the line is shut down for maintenance as planned, the maintenance personnel first connect the modules of the electric pickup truck, connect the power output box of the electric pickup truck to the distribution network maintenance flow control box, connect the three-phase voltage signal of the distribution network to the power output box, and then switch the power output box to the "grid-connected" mode. At this time, the electric pickup truck will output a three-phase power supply with the same amplitude and phase as the three-phase voltage of the distribution network; finally, close the backup circuit in the distribution network maintenance flow control box, and meet the power switching logic conditions, then the user's power supply can be transferred from the distribution network to the electric pickup truck, and the line power outage can start maintenance work; after the maintenance work is completed and the line has resumed power supply, close the distribution network power supply circuit breaker switch in the distribution network maintenance flow control box, and meet the power switching logic conditions, then the user's power supply can be transferred from the power supply vehicle to the distribution network; When a temporary power outage occurs due to a fault, the maintenance personnel first connect the modules of the electric pickup truck, connect the output of the power output box to the distribution network maintenance flow control box, and connect the distribution network synchronization wireless detector to the power output box. The subsequent operations are the same as those during the planned power outage maintenance. When the maintenance time is long and the electric pickup 1 is insufficient in power, the electric pickup 2 can be used to replace it; the working wiring of the electric pickup 2 is the same as that of the electric pickup 1.

[0013] The present invention provides a distribution network non-stop maintenance system and method, which has the following beneficial effects: 1. For users, during the planned maintenance of the substation, the power supply of users will not be affected during the entire maintenance process, which truly realizes the user's unawareness. When the substation is temporarily repaired due to a fault, the maintenance personnel can quickly deploy temporary power supply equipment and restore power supply to users. After completing the repair work, the power supply is transferred without power outage. The application of this method and device can significantly optimize the user's power consumption experience.

[0014] 2. For maintenance personnel, on the one hand, the use of combined electric vehicles can reduce the workload of carrying temporary power supply equipment, and the use of flow control boxes can quickly complete temporary cable access, which greatly improves work efficiency overall; on the other hand, the use of methods to carry out work can reduce the time and frequency of power outages in the substation area, and directly improve two important indicators: the average power outage time and the average number of power outages for users of the power supply distribution network. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a schematic diagram of the installation structure of the combined battery of the present invention; Figure 3a This is a front structural schematic diagram of the power output box of the present invention; Figure 3b It is a schematic diagram of the back structure of the power output box of the present invention; Figure 4 This is a power supply principle diagram of the electric pickup truck of the present invention; Figure 5 This is a schematic diagram of the AC / DC mixer of the present invention; Figure 6 This is a structural diagram of the distribution network maintenance flow control box of the present invention; Figure 7 is a control circuit diagram of the present invention; Figure 8 This is a power supply principle diagram of the present invention; Fig. 9 The schematic diagram of the working circuit of the comparator of the present invention is shown in FIG. Fig.10 It is the usage structure diagram of the lifting trolley of the present invention. DETAILED DESCRIPTION

[0016] like Figure 1As shown, a distribution network non-stop maintenance system includes a 10kVPT cabinet, a 10kV switch cabinet and a 10kV transformer connected in sequence, the 10kV transformer is connected to the distribution network maintenance flow control box and then connected to the user, and also includes an electric pickup truck for power supply, the electric pickup truck is connected to the distribution network maintenance flow control box, the 10kVPT cabinet is connected to the synchronous detector transmitter, the synchronous detector transmitter is wirelessly connected to the synchronous detector receiver, and the synchronous detector receiver is connected to the electric pickup truck; the electric pickup truck is equipped with a combined battery.

[0017] Preferably, Figure 2 As shown, the combined battery and the vehicle-mounted battery of the electric pickup truck are connected to the power output box, and the combined battery and the power output box are arranged in the rear box of the electric pickup truck. After the combined battery is pushed into the rear box, it is fixed at the innermost side, and then the vehicle-mounted output and the combined battery output are respectively connected to the power cabinet.

[0018] Power output box Figure 3a , 3b As shown, it is a combination of an AC / DC mixer, a three-phase AC signal source, and a power output box. It has a rectangular structure, and the front has status indicator lights (battery access, vehicle access, three-phase output, synchronous signal), a 380V output interface, a working mode selection switch, a connection button, a disconnect button, an output voltage display, and an output current display. The back has a battery interface (DC), a vehicle interface (AC), and a three-phase voltage signal interface.

[0019] Preferably, Figure 4 As shown, the combined battery is connected to the AC / DC mixer, the vehicle battery is connected to the AC / DC mixer through the vehicle inverter, the AC / DC mixer is connected to the power output box, and the AC / DC mixer also collects the three-phase AC voltage signal from the receiving end of the synchronous detector. First, the battery output is connected to the battery interface (DC) of the power cabinet, the vehicle inverter output is connected to the vehicle interface (AC) of the power cabinet, the three-phase output is connected to the load, and the three-phase voltage signal source of the distribution network is connected to the three-phase voltage signal interface, and then the working mode (grid-connected or independent) is selected. When working in the "grid-connected mode", the three-phase voltage value and phase output of the three-phase AC signal source are completely consistent with the three-phase voltage signal of the distribution network; when working in the "independent mode", the three-phase AC signal source will output a rated three-phase 380V power supply. The AC / DC mixer mixes the vehicle AC and battery DC according to the output signal of the three-phase AC signal source and then inverts and outputs the corresponding three-phase voltage. Finally, press the "on" button, the internal circuit of the power output box is turned on, and the electric energy is output from the three-phase output interface.

[0020] Preferably, Figure 5As shown, the AC / DC mixer includes a DC / AC power unit and a control unit. The combined battery and the vehicle battery are connected to the DC / AC power unit through a DC bus. The control unit receives a three-phase AC voltage signal and controls the triggering of the DC / AC power unit, thereby outputting 380V three-phase AC power.

[0021] The combined battery outputs 565V DC, which is directly connected to the DC bus. The on-board inverter outputs 220V AC, which is connected to the AC / DC / DC power unit. The unit uses high-frequency switching power supply technology, and rectifies 220V (AC) to 311V (DC) through an AC-DC converter. After that, it is boosted by the PFC power factor calibration circuit, and then sent to the switch circuit and transformer for variable frequency boosting. After the LLC is rectified and filtered for the second time, a high-voltage 565V (DC) is output to the DC bus. The control unit sends a trigger signal according to the three-phase AC voltage signal, controls the DC / AC power unit to perform inversion, and makes the three-phase voltage value and phase output by the AC / DC mixer completely consistent with the three-phase voltage signal.

[0022] Preferably, Figure 6 As shown, the distribution network maintenance flow control box includes a first terminal for connecting to the distribution network and a second terminal for connecting to the user, and two backup power supply branches are connected between the first terminal and the second terminal, specifically including a third terminal and a fourth terminal, and the third terminal and the fourth terminal are respectively connected to the power output boxes on the two electric pickup trucks.

[0023] Preferably, a circuit breaker, a first AC contactor and a second AC contactor are respectively provided between the first terminal, the third terminal and the fourth terminal and the second terminal, and also includes a control circuit for controlling the circuit breaker, the first AC contactor and the second AC contactor.

[0024] In the main circuit wiring, terminal 1 is connected to the 380V side bus of the 10kV transformer, terminal 2 is connected to the user side, terminal 3 is connected to the backup power supply 1, terminal 4 is connected to the backup power supply 2, a circuit breaker QF is installed between terminal 2 and terminal 1, an AC contactor KM1 is installed between terminal 2 and terminal 3, and an AC contactor KM2 is installed between terminal 2 and terminal 4; the control circuit draws energy from the distribution network, backup power supply 1, and backup power supply 2 respectively, supplies power to the DC control bus and the AC control bus, and is responsible for controlling the on and off of circuit breaker QF, AC contactor KM1, and AC contactor KM2.

[0025] The control circuit of this device is as follows Figure 7As shown. In the distribution network power supply circuit, SB1 is the opening button, SB2 is the closing button, S1 is the position converter of the circuit breaker QF, TQ is the opening coil of the circuit breaker QF, HQ is the closing coil of the circuit breaker QF, KA1 is the AC relay, KA1-1, KA1-2 and KA1-3 are the normally open nodes of the AC relay KA1, KT1, KT2, KT3 are time relays, KT1-1 is the normally closed node of the time relay KT1, KT2-1 is the normally open node of the time relay KT2, KT3-1 is the normally open node of the time relay KT3, and comparator 1 is used to determine whether the distribution network circuit meets the closing conditions; in the backup power supply 1 power supply circuit, SB3 is the opening button, SB4 is the closing button, KM1 is the AC contactor, KM1-1 is the normally open node of the AC contactor KM1, K A2 is an AC relay, KA2-1, KA2-2 and KA2-3 are the normally open nodes of AC relay KA1, KT1-2 is the normally closed node of time relay KT1, KT3-2 is the normally closed node of time relay KT3, and comparator 2 is used to determine whether the backup power supply 1 circuit meets the closing condition; in the backup power supply 2 power supply circuit, SB5 is the opening button, SB6 is the closing button, KM2 is an AC contactor, KM2-1 is the normally open node of AC contactor KM2, KA3 is an AC relay, KA3-1, KA3-2 and KA3-3 are the normally open nodes of AC relay KA1, KT1-3 is the normally closed node of time relay KT1, KT2-2 is the normally closed node of time relay KT2, and comparator 3 is used to determine whether the backup power supply 3 circuit meets the closing condition. PT1, PT2, PT3, PT4 are 4 Y / Y wiring isolation transformers used to measure the voltage of each phase at each terminal.

[0026] The power supply principle of the control box is as follows Figure 8 As shown, terminal 1, terminal 2, and terminal 3 are connected to the isolation transformer to output three DC power supplies and AC power supplies to supply power to different control circuits respectively.

[0027] The structures and principles of comparators 1, 2 and 3 are the same. The working circuit of comparator 1 is used for explanation. Fig. 9As shown. The three-phase voltage outputs VAN4, VBN4, and VCN4 on the secondary side of the isolation transformer PT4 are connected to amplifier 1, amplifier 2, and amplifier 3 respectively. Amplifier 1, amplifier 2, and amplifier 3 are connected to a NOR gate chip 7. The secondary side of the isolation transformer PT1 outputs three-phase voltages VAN1, VBN1, and VCN1. VAN1 and VAN4 are connected in series to amplifier 4, VBN1 and VBN4 are connected in series to amplifier 5, VCN1 and VCN4 are connected in series to amplifier 6, and amplifier 4, amplifier 5, and amplifier 6 are connected to a NOR gate chip 8. The outputs of the NOR gate chip 7 and the NOR gate chip 8 are connected to the OR gate chip 9, and the output of the OR gate chip 9 is connected to the BJT10 to control the DC relay KA6. KA6-1 is the normally open node of the DC relay KA6.

[0028] The power flow control box works normally, that is, the transformer provides power to the user, and the circuit breaker QF is in the closed state. At this time, the staff carries out line maintenance work (the transformer is out of power), and connects to the backup power supply 1. If the three-phase voltage amplitude and phase of the backup power supply 1 are consistent with the three-phase voltage amplitude and phase of the distribution network, the comparator 1 will be turned on, and the SB4 button will be pressed. The backup power supply 1 closing circuit will be turned on, and the KM1-1 normally open node will be energized. The user will be powered by the distribution network and the backup power supply 1 at the same time. After t seconds (the set time of KT2), ​​the normally open node KT2-1 of the time relay KT2 will be energized, the distribution network power supply disconnection circuit will be turned on, and the circuit breaker QF will be tripped. The user will be powered by the backup power supply 1 alone. When the maintenance work is completed and the distribution network has been powered, the SB2 button can be pressed to close the circuit breaker QF. After t seconds (the set time of KT1), the backup power supply 1 will be disconnected. If the backup power supply 1 is about to run out of power and the backup power supply 2 is needed, the SB6 button can be pressed to connect the backup power supply 2 circuit. After t seconds (the setting time of KT1), the backup power supply 1 is disconnected. From the beginning of maintenance to the restoration of power supply, the power flow control box can flexibly switch the power supply to meet the user's demand for non-stop power supply.

[0029] The distribution network synchronous wireless detector is used for line emergency repair work and is not required for planned power outage maintenance.

[0030] The distribution network synchronization wireless detector is divided into a transmitter and a receiver. First, the transmitter is responsible for measuring the three-phase voltage amplitude and phase from the secondary side of the 10kV bus voltage transformer, and sending it to the receiver after synchronization with the Beidou timing. Then, based on the set 10kV bus voltage transformer and the transformer ratio, the receiver calculates the three-phase voltage phase and amplitude on the low-voltage side of the transformer (i.e., the distribution network) from the three-phase voltage signal of the timing. Finally, the receiver outputs the three-phase AC voltage signal of the distribution network to the electric pickup truck.

[0031] Preferably, a lifting trolley for transporting the assembled battery is further included, the assembled battery is placed on the top of the lifting trolley, and the lifting trolley lifts the assembled battery to be flush with the rear box of the electric pickup truck. After being raised to the same plane as the rear box of the electric pickup truck, it is directly pushed into the car compartment.

[0032] When using: When the line is shut down for maintenance as planned, the maintenance personnel first connect the modules of the combined power supply vehicle, connect the output of the combined power supply vehicle to the flow control box, connect the three-phase voltage signal of the distribution network to the power box of the combined power supply vehicle, and then switch the combined power supply vehicle to the "grid-connected" mode and press "connect". At this time, the combined power supply vehicle will output a three-phase power supply with the same amplitude and phase as the three-phase voltage of the distribution network. Finally, press the closing button SB4 of the backup power supply circuit 1 of the flow control box. If the power switching logic conditions are met, the user's power supply can be transferred from the distribution network to the combined power supply vehicle, and the line power outage can start maintenance work. After the maintenance work is completed and the line has resumed power supply, press the closing button SB2 of the backup power supply circuit 1 of the flow control box. If the power switching logic conditions are met, the user's power supply can be transferred from the power supply vehicle to the distribution network.

[0033] When a temporary power outage occurs on the line due to a fault, the maintenance personnel first connect the modules of the combined power supply vehicle, connect the output of the combined power supply vehicle to the flow control box, and connect the distribution network synchronization wireless detector to the power box of the combined power supply vehicle. The subsequent operations are the same as those during the planned power outage maintenance.

[0034] When the maintenance time is long and the power supply of combined power supply car 1 is insufficient, combined power supply car 2 can continue to replace it. The working wiring of combined power supply car 2 is the same as that of combined power supply car 1, and it is switched through the closing button SB6 of the backup power supply circuit 2 of the flow control box.

[0035] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A distribution network non-stop maintenance system, comprising a 10kVPT cabinet, a 10kV switch cabinet and a 10kV transformer connected in sequence, characterized in that: The 10kV transformer substation is connected to the distribution network maintenance flow control box and then to the user. It also includes an electric pickup truck for power supply. The electric pickup truck is connected to the distribution network maintenance flow control box, the 10kVPT cabinet is connected to the synchronous detector transmitter, the synchronous detector transmitter is wirelessly connected to the synchronous detector receiver, and the synchronous detector receiver is connected to the electric pickup truck; the electric pickup truck is equipped with a combined battery.

2. According to claim 1, a distribution network non-stop maintenance system is characterized by: The combined battery and the on-board battery of the electric pickup truck are both connected to a power output box, and the combined battery and the power output box are arranged in the rear bucket of the electric pickup truck.

3. According to claim 2, a distribution network non-stop maintenance system is characterized by: The combined battery is connected to the AC / DC mixer, the vehicle-mounted battery is connected to the AC / DC mixer via the vehicle-mounted inverter, the AC / DC mixer is connected to the power output box, and the AC / DC mixer also collects the three-phase AC voltage signal transmitted from the receiving end of the synchronization detector.

4. A distribution network non-stop maintenance system according to claim 3, characterized in that: The AC / DC mixer includes a DC / AC power unit and a control unit. The combined battery and the vehicle battery are connected to the DC / AC power unit through a DC bus. The control unit receives a three-phase AC voltage signal and controls the triggering of the DC / AC power unit, thereby outputting 380V three-phase AC power.

5. A distribution network non-stop maintenance system according to claim 4, characterized in that: The distribution network maintenance flow control box includes a first terminal for connecting to the distribution network and a second terminal for connecting to the user. Two backup power supply branches are connected between the first terminal and the second terminal, specifically including a third terminal and a fourth terminal. The third terminal and the fourth terminal are respectively connected to the power output boxes on the two electric pickup trucks.

6. A distribution network non-stop maintenance system according to claim 5, characterized in that: A circuit breaker, a first AC contactor and a second AC contactor are respectively arranged between the first terminal, the third terminal and the fourth terminal and the second terminal, and also includes a control circuit for controlling the circuit breaker, the first AC contactor and the second AC contactor.

7. The non-stop maintenance system for distribution network according to claim 1, characterized in that: It also includes a lifting trolley for transporting the combined battery. The combined battery is placed on the top of the lifting trolley, and the lifting trolley lifts the combined battery to be flush with the rear bucket of the electric pickup truck.

8. The method for using the distribution network non-stop maintenance system as claimed in claim 6, characterized in that: When the line is shut down for maintenance as planned, the maintenance personnel first connect the modules of the electric pickup truck, connect the power output box of the electric pickup truck to the distribution network maintenance flow control box, connect the three-phase voltage signal of the distribution network to the power output box, and then switch the power output box to the "grid-connected" mode. At this time, the electric pickup truck will output a three-phase power supply with the same amplitude and phase as the three-phase voltage of the distribution network; finally, close the backup circuit in the distribution network maintenance flow control box, and meet the power switching logic conditions, then the user's power supply can be transferred from the distribution network to the electric pickup truck, and the line power outage can start maintenance work; after the maintenance work is completed, the line has resumed power supply, and the distribution network power supply circuit breaker switch in the distribution network maintenance flow control box is closed. When the power switching logic conditions are met, the user's power supply can be transferred from the power supply vehicle to the distribution network; When a temporary power outage occurs due to a fault, the maintenance personnel first connect the modules of the electric pickup truck, connect the output of the power output box to the distribution network maintenance flow control box, and connect the distribution network synchronization wireless detector to the power output box. The subsequent operations are the same as those during the planned power outage maintenance. When the maintenance time is long and the electric pickup 1 is insufficient in power, the electric pickup 2 can be used to replace it; the working wiring of the electric pickup 2 is the same as that of the electric pickup 1.

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