Ring network controller and control method

Abstract

A ring network controller and control method are provided. The ring network controller is installed at the busbar outlets on both sides of the ring network circuit and includes: a lightning arrester, a switch device, and a control device; the lightning arrester is connected in parallel with the switch device; the control device is connected to the switch device and is used to collect ring network circuit data and control the switch device to open or close according to the ring network circuit data; the lightning arrester is used for overvoltage protection; the switch device is used to construct and eliminate breakpoints and bear the corresponding voltage difference. By installing the ring network controller of this solution at the busbar outlets on both sides of the ring network circuit, the ring can be closed first and then opened during the line switching operation. The switch device constructs breakpoints when closing the ring and eliminates breakpoints when opening the ring, effectively eliminating the ring closing impact of the ring network circuit, solving the problem of power outages during the process of transferring line loads due to reasons such as line maintenance, and improving the power supply reliability of important loads.

Description

Technical Field

[0001] The present invention relates to the field of live ring closing of distribution networks, and in particular to a ring network controller and a control method. Background Art

[0002] Grid users are increasingly demanding higher reliability in their power supply. Industrial users, in particular, are highly sensitive to power outages, with even short outages potentially causing significant economic losses. However, distribution network outages for maintenance are frequent, and distribution network voltage levels are not limited to 10kV, but include at least 6kV, 10kV, 20kV, or 35kV. Medium and low voltage distribution networks typically employ a closed-loop design with open-loop operation. This means that one loop operates in a decoupled loop, with each power source supplying a portion of the load. Currently, for load reversal and line maintenance, the decoupled loop typically involves first opening the circuit breaker at the target decoupled position and then closing it at the original decoupled position—a "open-first, close-later" approach. This process can cause partial power outages. Adopting a "close-first, open-later" approach—first closing the circuit breaker at the original decoupled position (i.e., closing the loop first) and then opening the circuit breaker at the target decoupled position—can reduce power outages and improve power supply reliability.

[0003] However, directly performing the disconnection operation without power outages presents significant risks. This is because closing the loop directly in an open-loop distribution network presents the following issues: Due to the voltage difference between the two ends of the loop closing point before closing, a large surge current is typically generated during closing, and after closing, a circulating current in the electromagnetic loop network exists. This surge current can also cause malfunctions in the distribution network's relay protection, resulting in faults. Furthermore, on-site loop closing operations are conducted based on the operator's experience, resulting in a high degree of randomness in the results, potentially posing a safety hazard to related equipment and operators. Summary of the Invention

[0004] In order to solve the problem of ring closing impact occurring when closing a distribution network in the prior art, the present invention provides a ring network controller and a control method.

[0005] The technical solution provided by the present invention is:

[0006] A ring network controller, the ring network controller being connected in series to a busbar outlet of the ring network circuit, comprising:

[0007] lightning arresters, switchgear, and controlgear;

[0008] The lightning arrester is connected in parallel with the switchgear;

[0009] The control device is connected to the switch device and is used to collect ring network circuit data and control the switch device to open or close according to the ring network circuit data;

[0010] The lightning arrester is used for overvoltage protection;

[0011] The switching device is used to construct and eliminate breakpoints and bear the corresponding voltage differences.

[0012] Preferably, the switching device may be one or more of a mechanical switch and a power electronic device.

[0013] Preferably, the switch device comprises:

[0014] Mechanical switches and power electronics;

[0015] The mechanical switch and power electronic device are connected in series or in parallel and then connected in parallel with the lightning arrester;

[0016] The mechanical switch and the power electronic device are also connected to the control device.

[0017] Preferably, the power electronic device should be able to withstand the short-circuit impact current of the ring network circuit.

[0018] Preferably, the mechanical switch should be able to withstand the short-circuit impact current of the ring network circuit, and the terminal withstand voltage level of the mechanical switch may not be equal to the insulation voltage level of the mechanical switch to the ground;

[0019] The mechanical switch can operate in three phases separately or in a three-phase linkage manner.

[0020] Preferably, the arrester may be a metal oxide arrester, a valve type arrester, a metal oxide arrester connected in series with a resistive inductive element, or a valve type arrester connected in series with a resistive inductive element;

[0021] The continuous operating voltage of the lightning arrester should be greater than the maximum break voltage that occurs at the installation location of the ring network controller during steady-state operation.

[0022] Preferably, the control device includes:

[0023] Interconnected measurement modules and control modules;

[0024] The control module is connected to the mechanical switch and the power electronic device;

[0025] The measuring module is used to collect current data flowing through the ring network controller and voltage data near the load side or near the bus side, and formulate an opening instruction or a closing instruction according to the current and voltage data;

[0026] The control module is used to control the mechanical switch to be disconnected or closed according to the opening instruction or closing instruction;

[0027] The voltage data on the near-load side includes: the instantaneous voltage difference at both ends of the ring network controller and the instantaneous voltage value on the near-load side;

[0028] The voltage data near the bus side includes: the instantaneous voltage value near the bus side and the instantaneous voltage difference between the two ends of the ring network controller or the instantaneous voltage value near the bus side and the instantaneous voltage value near the load side.

[0029] Preferably, the measurement module may be a conventional mutual inductor or sensor.

[0030] Preferably, the voltage instantaneous difference measurement in the measurement module can be implemented by a breakdown diode BOD, which is used to reflect the voltage instantaneous difference across the ring network controller;

[0031] The breakdown diode BOD is connected in parallel at both ends of the ring network controller;

[0032] The breakdown voltage of the breakdown diode BOD is equal to the set voltage difference instantaneous threshold.

[0033] Preferably, the control device may be a device that takes energy from voltage and supplies energy.

[0034] Preferably, the lightning arrester, power electronic device, mechanical switch, measurement module and control module are fixedly installed at the busbar outlet of the ring network circuit.

[0035] Preferably, the lightning arrester, power electronic device and mechanical switch are fixedly installed at the busbar outlet of the ring network circuit;

[0036] When the ring network circuit is closed or opened, the measuring module and the control module are connected to the lightning arrester, the power electronic device and the mechanical switch as the moving parts.

[0037] Preferably, when there is a switchgear at the busbar outlet of the ring network circuit, the lightning arrester, power electronic device, mechanical switch, measurement module and control module can be installed as movable parts at the busbar outlet of the ring network circuit.

[0038] Preferably, a ring network controller is installed between the busbar outlets on both sides of the ring network circuit and the first load corresponding to each.

[0039] Preferably, the ring network controller can be installed in the substation at the busbar outlet, on the line between the busbar outlet and the first ring network cabinet, on the low-voltage side of the first box-type transformer after the busbar outlet, or inside or next to the first ring network cabinet after the busbar outlet.

[0040] Preferably, when the ring network circuit is a single ring network, the ring network controller is installed at the two busbar outlets of the single ring network, and two ring network controllers are installed in the line of the single ring network connection;

[0041] When the ring network circuit is a double ring network, the ring network controller is installed at the four busbar outlets of the double ring network, and a total of four ring network controllers are installed in the double ring network wiring line;

[0042] When the ring network circuit is an N-supply and one-backup wiring distribution network, the ring network controller is installed at all busbar outlets of the N-supply and one-backup wiring distribution network, and a total of N+1 ring network controllers need to be installed in the N-supply and one-backup wiring line;

[0043] When the ring network circuit is an N-1 wiring distribution network, the ring network controller is installed at all busbar outlets of the N-1 wiring distribution network, and a total of N ring network controllers need to be installed in the N-1 wiring line.

[0044] A control method for a ring network controller, comprising:

[0045] When the ring network circuit is closed, the control device installed in the ring network controller at the busbar outlet of the ring network circuit controls the switch device in the ring network controller to open the breakpoint according to the collected ring network circuit data, thereby eliminating the closing impact in the ring network circuit;

[0046] When the ring network circuit is unhooked, the control device controls the switching device to close according to the collected ring network circuit data to eliminate the breakpoint, bypass the lightning arrester, and restore the ring network circuit voltage.

[0047] Preferably, when the ring network circuit is closed, a control device installed in a ring network controller at a busbar outlet of the ring network circuit controls a switch device in the ring network controller to open a breakpoint according to the collected ring network circuit data, thereby eliminating a closing impact in the ring network circuit, including:

[0048] The measurement module in the control device collects the current data flowing through the ring network controller and the voltage data near the load side or the bus side in real time;

[0049] When the ring network circuit is closed, the measuring module formulates an opening instruction according to the current data flowing through the ring network controller and the voltage data near the load side or the bus side;

[0050] The control module controls the switching device to open according to the opening instruction, thereby eliminating the closing impact in the ring network circuit.

[0051] Preferably, when the ring network circuit is closed, the measurement module formulates a tripping instruction based on the current data flowing through the ring network controller and the voltage data near the load side or near the bus side, including:

[0052] The measuring module calculates the voltage effective value and active power according to the current data flowing through the ring network controller and the voltage data near the load side or near the bus side;

[0053] The measuring module determines whether active power reverse transmission occurs in the current ring network controller according to the active power. If active power reverse transmission occurs and the effective value of the voltage near the load side or the bus side is greater than a set threshold, a trip signal is generated; otherwise, no trip signal is generated.

[0054] The time from the occurrence of active power backflow to the completion of the opening of the switching device should ensure that the line overcurrent protection with the fastest action in the line does not operate.

[0055] Preferably, the determination of the active power reverse transmission includes:

[0056] The instantaneous value of the current flowing through the ring network controller and the instantaneous value of the voltage near the load side or the bus side are collected through the measurement module;

[0057] The direction of active power can be determined by calculating the angle between the voltage and current fundamental components and the size of the angle;

[0058] If the active power is injected into the bus side, the active power is reversed; if the active power is injected into the load side, the active power is not reversed.

[0059] Preferably, the control module controls the switching device to open according to the opening instruction, including:

[0060] The control module controls the mechanical switch in the switch device to open according to the opening instruction, turns on the power electronic device in the switch device after a first set delay, and turns off the power electronic device after a second set delay;

[0061] When the first set delay is reached, the mechanical switch has not yet started to open;

[0062] When the second set delay is reached, the mechanical switch has been opened and the arc has been extinguished.

[0063] Preferably, the control device controls the switching device to close to eliminate the breakpoint, bypass the lightning arrester, and restore the ring network circuit voltage based on the collected ring network circuit data, including:

[0064] The instantaneous voltage difference between the two ends of the ring network controller is collected by a measurement module in the control device;

[0065] If the instantaneous voltage difference between the two ends of the ring network controller is greater than a set threshold, a closing command is issued;

[0066] The control module controls the switching device to close according to the closing instruction, so as to quickly restore the ring network circuit voltage;

[0067] The time from the moment when the instantaneous voltage difference across the ring network controller is greater than the threshold to the moment when the switching device is closed is within 10ms.

[0068] Preferably, the control module controls the switching device to close according to the closing instruction, including:

[0069] The control module controls the triggering of the power electronic device and the closing of the mechanical switch according to the closing instruction, and cuts off the power electronic device after a third set delay;

[0070] When the third set delay is reached, the mechanical switch completes closing and carries the load current.

[0071] Preferably, the control module controls the switching device to close according to the closing instruction, and further includes:

[0072] The control module controls the mechanical switch in the switch device to close.

[0073] Compared with the prior art, the present invention has the following beneficial effects:

[0074] The ring network controller in the technical solution provided by the present invention is connected in series at the busbar outlet of the ring network circuit, and includes: a lightning arrester, a switch device and a control device; the lightning arrester is connected in parallel with the switch device; the control device is connected to the switch device, and is used to collect ring network circuit data and control the switch device to open or close according to the ring network circuit data; the lightning arrester is used for overvoltage protection; the switch device is used to construct and eliminate breakpoints and bear the corresponding voltage difference. By installing the ring network controller of this solution at the busbar outlets on both sides of the ring network circuit, it is possible to close the ring first and then open the ring when repairing the ring network. The switch device constructs breakpoints when closing the ring and eliminates breakpoints when opening the ring, effectively eliminating the ring closing impact of the ring network circuit, solving the power outage problem during the transfer of line loads due to reasons such as line maintenance, and improving the power supply reliability of important loads.

[0075] The ring network controller in this solution has a simple structure, including only lightning arresters, switchgear and control equipment, and requires little change to the distribution network. It has the advantages of low cost and simple operating principle. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 This is a structural effect diagram of a ring network controller of the present invention;

[0077] Figure 2 This is a schematic diagram of the installation of a ring network controller in a single ring network connection according to the present invention;

[0078] Figure 3 This is a schematic diagram of the installation of a ring network controller in a double ring network connection according to the present invention;

[0079] Figure 4 This is a schematic diagram of the installation of a ring network controller in an N-supply-one-standby wiring system according to the present invention;

[0080] Figure 5 This is a schematic diagram of the installation of a ring network controller in N-1 wiring according to the present invention;

[0081] Figure 6 A first embodiment diagram of a ring network controller of the present invention;

[0082] Figure 7 A second embodiment of a ring network controller according to the present invention;

[0083] Figure 8 FIG3 is a third embodiment of a ring network controller of the present invention;

[0084] Figure 9 FIG4 is a fourth embodiment diagram of a ring network controller of the present invention;

[0085] Figure 10 FIG5 is a fifth embodiment of a ring network controller of the present invention;

[0086] Figure 11 A sixth embodiment of a ring network controller according to the present invention;

[0087] Figure 12 A schematic diagram of a first operating principle of a ring network controller of the present invention;

[0088] Figure 13 A schematic diagram of a second operating principle of a ring network controller of the present invention;

[0089] Figure 14 A third operating principle diagram of a ring network controller of the present invention;

[0090] Figure 15 A fourth operating principle diagram of a ring network controller of the present invention;

[0091] Figure 16 A fifth operating principle diagram of a ring network controller of the present invention;

[0092] Figure 17 Schematic diagram of the sixth operating principle of a ring network controller of the present invention;

[0093] Figure 18 FIG7 is a seventh operating principle diagram of a ring network controller of the present invention;

[0094] Figure 19 Schematic diagram of the eighth operating principle of a ring network controller of the present invention;

[0095] Figure 20FIG9 is a ninth operating principle diagram of a ring network controller according to the present invention;

[0096] Figure 21 FIG10 is a schematic diagram of the tenth operating principle of a ring network controller of the present invention;

[0097] Figure 22 This is an eleventh operating principle diagram of a ring network controller of the present invention. DETAILED DESCRIPTION

[0098] In order to better understand the present invention, the present invention is further described below with reference to the accompanying drawings and examples.

[0099] Example 1:

[0100] This embodiment provides a ring network controller, the structure effect diagram is as follows Figure 1 shown.

[0101] A ring network controller consists of a lightning arrester and a switch, which are connected in series in the line.

[0102] The switches in the ring network controller can be traditional switches with contacts, power electronic devices, or both in series or in parallel. The switches in the ring network controller can be power electronic devices such as thyristors. They can also use traditional switches in series with resistive and inductive elements, or power electronic devices in series with resistive and inductive elements, or both in parallel. Mechanical switches and thyristor devices are used to create and eliminate breakpoints, balancing the corresponding voltage differences.

[0103] Thyristor equipment should be able to withstand line short-circuit impact current.

[0104] Mechanical switchgear should be able to withstand line short-circuit impulse current, and the withstand voltage level between the terminals of the mechanical switchgear may not be equal to its insulation voltage level to ground.

[0105] The ring network controller in this embodiment also includes a control device, including a measuring module and a control module. The measuring module is used to collect and calculate the effective value U1 of the voltage at the connection point between the ring network controller and the line, the instantaneous value U2 of the voltage difference between the two ends, and the direction of the active power P flowing through the device. When measuring the voltage difference between the two ends of the ring network controller, the measuring module can use conventional mutual inductors and sensors. The measurement of the instantaneous voltage difference between the two ends of the ring network controller can be achieved by using a breakdown diode BOD to reflect the instantaneous voltage difference between the two ends of the ring network controller, that is, a breakdown diode BOD is connected in parallel at both ends of the ring network controller. The breakdown voltage of BOD is equal to U thr , U thr It is the instantaneous voltage threshold value at both ends of the ring network controller. Therefore, when BOD breaks down, it can be considered that U2 exceeds the set value U thrThe control module is used to control the opening and closing of the mechanical switching device and the cutoff and triggering of the thyristor device according to the control signal.

[0106] The arrester in the ring network controller can be a metal oxide arrester or a valve type arrester, or a metal oxide arrester in series with a resistive and inductive element, or a valve type arrester in series with a resistive and inductive element. The continuous operating voltage of the arrester should be greater than the maximum break voltage that would occur at the ring network controller installation during steady-state operation to ensure normal operation of the ring network controller during normal parallel and parallel operation.

[0107] Example 2:

[0108] This embodiment provides a control method for a ring network controller, which can assist in power outage and decommissioning operations. The specific contents are as follows:

[0109] The ring network controller collects and calculates the effective value of the voltage U1 at the connection point with the line, the instantaneous voltage difference U2 at both ends and the direction of the active power P flowing through the device.

[0110] Two ring network controllers are installed in a ring network, one at the outgoing line of the busbars on either side of the ring network. During normal operation, the two ring network controllers are in conduction, and the busbars on both sides are normally supplying power to their respective loads.

[0111] During line closing, if a closing impulse current is generated, only one ring network controller will be activated, forming a breakpoint, disconnecting the busbar on the side where the ring network controller is installed from the rest of the ring network. All loads in the ring network will be temporarily powered by the busbar on the other side.

[0112] After the line is unlooped, ensure that the ring network returns to normal open-loop operation.

[0113] When the ring network controller detects that P < 0 and U1 is greater than the set threshold U L , the switch switches from the on state to the off state and the circuit breaker is opened. The time from the occurrence of active power reverse flow (P < 0) to the completion of the circuit breaker opening should ensure that the overcurrent protection of the fastest-acting line in the line does not operate.

[0114] When the ring network controller detects that U2 is greater than the set threshold U thr , it switches from the disconnected state to the conductive state and closes the circuit. thr ) to the completion of closing, the time taken should be within 10ms to ensure that there is no power quality problem such as voltage sag or even interruption on the line.

[0115] The switch opening time should ensure that the fastest-acting overcurrent protection in the line does not operate. The switch opening time should be less than 0.3s. The switch closing time should be less than 10ms to ensure that no power quality issues occur on the line. The switch can operate independently of the three phases or in a coordinated manner.

[0116] When the ring network controller collects the voltage at the connection point between it and the line, it can obtain the instantaneous value of the line voltage close to the bus side or the line side, or the instantaneous value of the three-phase phase voltage through the measurement module.

[0117] When the ring network controller collects the voltage difference between its two ends, it can be obtained by measuring the instantaneous value of the voltage difference between the two ends of the ring network controller, or by measuring the instantaneous voltage values ​​on the bus side and the line side of the ring network controller and then subtracting them. To ensure that there are no power quality problems on the measurement line, this measurement delay should be less than 10ms.

[0118] When the ring network controller determines the direction of the active power flowing through the device, the three-meter method can be used to obtain the size and direction of the active power flowing through the ring network controller.

[0119] After measuring the voltage and current at the connection point between the ring network controller and the line, the product of the two is integrated to obtain the magnitude and direction of the active power flowing through the device.

[0120] After measuring the voltage and current at the connection point between the ring network controller and the line, perform orthogonal decomposition on the fundamental wave components and use the decomposition to calculate the active power. Alternatively, perform orthogonal decomposition on the fundamental wave and harmonic components of the voltage and current at the connection point between the ring network controller and the line, calculate the active power corresponding to the fundamental wave and each harmonic component, and finally add them together to obtain the magnitude and direction of the active power flowing through the device.

[0121] After measuring the voltage and current at the connection point between the ring network controller and the line, calculate the angle between the voltage and current, and determine the direction of the active power flowing through the device based on the size of the angle.

[0122] Example 3:

[0123] This embodiment provides a control method for a ring network controller.

[0124] The measuring device of the ring network controller is used to measure the instantaneous value U1 of the voltage near the load side of the ring network controller, the instantaneous value i of the current near the load side, and the instantaneous value U2 of the voltage difference between the two ends of the ring network controller.

[0125] The function of the measurement submodule is to take the effective value of the voltage U1 at the connection between the ring network controller and the line, and the instantaneous voltage difference U2 at both ends of the ring network controller as input; calculate the effective value of the voltage U1 at the side of the ring network controller close to the load 1rms And active power P; U L 、U thr , active power threshold (0) is the set value; U 1rms with U L , U2 and U thr, P is compared with 0, and according to the comparison result, it is determined whether to output a trigger signal to the thyristor device, and whether to output a closing or opening signal to the mechanical switch device, and the operation is controlled by the control submodule.

[0126] The ring network controller includes opening action logic and closing action logic.

[0127] Opening action logic: If it is determined that P < 0 and U 1rms >U L , then immediately send a trip command to the mechanical switch device, and after a delay t1 send a trigger command to the thyristor device, and after the delay t2 is reached, stop triggering the thyristor.

[0128] The delay t1 should ensure that the thyristor has been triggered when the mechanical switch starts to open.

[0129] The delay t2 should ensure that the mechanical switch is opened and the arc is extinguished before stopping triggering the thyristor.

[0130] Closing action logic: If it is determined that U2>U thr , the thyristor device trigger signal and the mechanical switch device closing signal are immediately issued. The thyristor device is triggered first, and then the mechanical switch device is closed. After the mechanical switch device is closed, the thyristor device is stopped after a delay t3.

[0131] The delay t3 should ensure that the mechanical switch completes the closing action and carries the corresponding load current before stopping triggering the thyristor.

[0132] If the mechanical switchgear closes quickly enough, the ring network controller determines that U2>U thr After that, a closing signal is immediately sent to the mechanical switch device without sending a trigger signal to the thyristor device.

[0133] In addition, during the normal open-loop operation of the ring network, both ring network controllers in the ring network are in the closed state; during the line fault period, the closed state should be maintained, or due to the determination that U2>U thr And quickly switch to the closing state.

[0134] Example 4:

[0135] This embodiment provides an installation location and installation method for a ring network controller.

[0136] Two controllers need to be installed in a ring network, one at the bus outlet on both sides of the ring network. During normal operation, the two ring network controllers are in conduction state, and the busbars on both sides normally supply power to their respective loads.

[0137] The ring network controller can be installed in the substation at the busbar outlet, on the line between the busbar outlet and the first ring network cabinet, on the low-voltage side of the first box-type transformer after the busbar outlet, or inside or next to the first ring network cabinet after the busbar outlet.

[0138] The lightning arrester, power electronic device and mechanical switch can be fixedly installed at the busbar outlet of the ring network circuit;

[0139] The measuring module and the control module can serve as mobile parts and be connected to the lightning arrester, the power electronic device and the mechanical switch when closing or opening the ring network.

[0140] When there is a switching device at the busbar outlet of the ring network circuit that can be used to bypass the ring network controller, the lightning arrester, power electronic devices, mechanical switch, measurement module and control module can be used as mobile parts. When closing or opening the ring network, they are connected to the original switching device at the busbar outlet and installed at the busbar outlet of the ring network circuit.

[0141] When the ring network circuit is a single ring network, the ring network controller is installed at the two busbar outlets of the single ring network. Two ring network controllers are installed in the line of the single ring network wiring. The schematic diagram is as follows Figure 2 shown.

[0142] When the ring network circuit is a double ring network, the ring network controller is installed at the four busbar outlets of the double ring network. A total of four ring network controllers are installed in the double ring network wiring line, as shown in the schematic diagram. Figure 3 shown.

[0143] When the ring network circuit is an N-supply and one-backup wiring distribution network, the ring network controller is installed at all busbar outlets of the N-supply and one-backup wiring distribution network. A total of N+1 ring network controllers need to be installed in the N-supply and one-backup wiring line. The schematic diagram is as follows: Figure 4 shown.

[0144] When the ring network circuit is an N-1 wiring distribution network, the ring network controller is installed at all bus outlets of the N-1 wiring distribution network. A total of N ring network controllers need to be installed in the N-1 wiring line. The schematic diagram is as follows: Figure 5 shown.

[0145] Example 5:

[0146] During normal operation, if Figure 6 The 10kV distribution network shown is open at Brk2. If it is closed directly, a closing surge current will flow from 10kV bus B to 10kV bus A. Now it is necessary to transfer part of the load from 10kV bus A to 10kV bus B for power supply. In other words, the open position is switched from Brk2 to Brk1. The operation process is as follows:

[0147] When Brk2 is closed, a closing surge current flows from 10kV bus B to 10kV bus A in the distribution network, such as Figure 7 shown.

[0148] Ring network controller A detects that P < 0 and U1 > U L , then it switches from the on state to the off state, and the ring network controller B does not operate. All loads are temporarily powered by the 10kV bus B, and the ring closing impact current disappears. Figure 8 Show.

[0149] Open Brk1, such as Figure 9 As shown in Figure 1, the load between Brk1 and ring network controller A loses power temporarily, and the voltage drops rapidly.

[0150] The input voltage of the ring network controller is the voltage of 10kV bus A, and the output voltage drops rapidly. Therefore, the voltage difference between the two ends of the ring network controller becomes larger and larger. Ring network controller A detects that U2>U thr , quickly switches from the off state to the on state. Figure 10 shown.

[0151] If a line fault occurs, the fault may occur in Figure 11 ①, ②, ③ or other positions. At this time, the ring network controller A and B remain in the on state, or because U2>U thr , quickly switching from the off state to the on state.

[0152] Example 6:

[0153] This embodiment illustrates the operating principle of the ring network controller.

[0154] Install ring network controllers at both ends of a ring network. Under normal circumstances, the mechanical switch devices S A 、S B In the closed position, the thyristor device T A 、T B Shut down, arrester device A rA 、A rB In the disconnected state, such as Figure 12 shown.

[0155] If the system is fault-free, the parallel operation is carried out. If the ring closing impact is not large after closing, and there is no active power reverse transmission on the load side of the two ring network controllers, the two ring network controllers will maintain Figure 12 The status remains unchanged.

[0156] If the impact after closing the loop is large, the closing current will flow from bus B to bus A. Figure 13 As shown in . At this time, the electrical characteristics are: the active power P at the ring network controller A 1A Backfeed (abbreviated as P 1A<0), the voltage U of the ring network controller close to the load side 1A Normal (U 1A The effective value is greater than the fixed value U L ), the active power at ring network controller B is not reversed. At this time, the ring network controller operates as follows:

[0157] Process 1: Ring network controller B does not act. After the ring network controller A determines that the active power is reversed, it immediately issues S A The opening command is sent to T after a delay of t1. A Send a trigger signal, T A In S A Triggered before the opening is completed, such as Figure 14 shown.

[0158] Process 2: S A Open the gate as Figure 15 shown.

[0159] Process 3: After a delay t2, the triggering T A , T A Shutdown, S A A disconnection point is formed, and all loads in the ring network are powered by bus B. Figure 16 shown.

[0160] Process 4: After the loop is unwound at the new opening point, U 1A Descending, A rA Actions, such as Figure 17 shown.

[0161] Process 5: Ring network controller A detects U 2A >U thr , then trigger T A , issue S A Closing command, such as Figure 18 shown.

[0162] Process 6: S A After closing, after a corresponding delay, stop triggering T A , and the solution operation is completed, such as Figure 19 shown.

[0163] If S A If the action is fast enough, the above process 5 and process 6 can be simplified as follows: Ring network controller A detects U 2A >U thr , issue S A Closing command, S A Close the circuit breaker.

[0164] When a short circuit fault occurs in the ring network line, the ring network controller device should maintain or switch to the state where the mechanical switch device is closed and the thyristor device is cut off. For example, during the closing operation, the ring network controller has formed a disconnection point and a ground short circuit fault occurs in the ring network. First, A rA Action pressure limit, such as Figure 20 Then, trigger and turn on T A ,like Figure 21 As shown in; Finally, S A After closing the circuit breaker and the corresponding delay has passed, the triggering of T A ,like Figure 22 As shown in .

[0165] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0166] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0167] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0168] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0169] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0170] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of the claims of the present invention to be approved.

Claims

1. A control method for a ring network controller, characterized in that: include: When the ring network circuit is closed, the control device installed in the ring network controller at the busbar outlet of the ring network circuit controls the switch device in the ring network controller to open the breakpoint according to the collected ring network circuit data, thereby eliminating the closing impact in the ring network circuit. Specifically, the control device includes: The measurement module in the control device collects the current data flowing through the ring network controller and the voltage data near the load side or near the bus side in real time; When the ring network circuit is closed, the measuring module formulates an opening instruction according to the current data flowing through the ring network controller and the voltage data near the load side or the bus side; The control module controls the switch device to open according to the opening instruction, thereby eliminating the ring closing impact in the ring network circuit; When the ring network circuit is closed, the measurement module formulates a tripping instruction based on the current data flowing through the ring network controller and the voltage data near the load side or the bus side, including: The measuring module calculates the voltage effective value and active power according to the current data flowing through the ring network controller and the voltage data near the load side or near the bus side; The measuring module determines whether active power reverse transmission occurs in the current ring network controller according to the active power. If active power reverse transmission occurs and the effective value of the voltage near the load side or the bus side is greater than a set threshold, a trip signal is generated; otherwise, no trip signal is generated. The time from the occurrence of active power reverse flow to the completion of the opening of the switching device should ensure that the fastest-acting line overcurrent protection in the line does not operate; When the ring network circuit is disconnected, the control device controls the switching device to close according to the collected ring network circuit data to eliminate the breakpoint, bypass the lightning arrester, and restore the ring network circuit voltage; The ring network controller is connected in series to the bus outlet of the ring network circuit, and includes: lightning arresters, switchgear, and controlgear; The lightning arrester is connected in parallel with the switchgear; The control device is connected to the switch device and is used to collect ring network circuit data and control the switch device to open or close according to the ring network circuit data; The lightning arrester is used for overvoltage protection; The switching device is used to construct and eliminate breakpoints and bear the corresponding voltage differences.

2. The method according to claim 1, wherein The switch device is one or more of a mechanical switch and a power electronic device.

3. The method according to claim 2, wherein The switch device comprises: Mechanical switches and power electronics; The mechanical switch and power electronic device are connected in series or in parallel and then connected in parallel with the lightning arrester; The mechanical switch and the power electronic device are also connected to the control device.

4. The method according to claim 2, wherein The power electronic device should be able to withstand the short-circuit impact current of the ring network circuit.

5. The method according to claim 2, wherein The mechanical switch should be able to withstand the short-circuit impact current of the ring network circuit, and the terminal withstand voltage level of the mechanical switch is not equal to the insulation voltage level of the mechanical switch to ground; The mechanical switch operates in three phases separately or in a three-phase linkage manner.

6. The method according to claim 1, wherein: The arrester is a metal oxide arrester, a valve type arrester, a metal oxide arrester connected in series with a resistive and inductive element, or a valve type arrester connected in series with a resistive and inductive element; The continuous operating voltage of the lightning arrester should be greater than the maximum break voltage that occurs at the installation location of the ring network controller during steady-state operation.

7. The method according to claim 3, wherein The control device comprises: Interconnected measurement modules and control modules; The control module is connected to the mechanical switch and the power electronic device; The measuring module is used to collect current data flowing through the ring network controller and voltage data near the load side or near the bus side, and formulate an opening instruction or a closing instruction based on the current and voltage data; The control module is used to control the mechanical switch to be disconnected or closed according to the opening instruction or closing instruction; The voltage data on the near-load side includes: the instantaneous voltage difference at both ends of the ring network controller and the instantaneous voltage value on the near-load side; The voltage data near the bus side includes: the instantaneous voltage value near the bus side and the instantaneous voltage difference between the two ends of the ring network controller or the instantaneous voltage value near the bus side and the instantaneous voltage value near the load side.

8. The method according to claim 7, wherein The measuring module is a conventional mutual inductor or sensor.

9. The method according to claim 8, wherein The voltage instantaneous difference measurement in the measurement module is realized by a breakdown diode BOD, which is used to reflect the voltage instantaneous difference at both ends of the ring network controller; The breakdown diode BOD is connected in parallel at both ends of the ring network controller; The breakdown voltage of the breakdown diode BOD is equal to the set voltage difference instantaneous threshold.

10. The method according to claim 1, wherein The control device is a device that obtains energy from voltage.

11. The method according to claim 7, wherein The lightning arrester, power electronic device, mechanical switch, measurement module and control module are fixedly installed at the busbar outlet of the ring network circuit.

12. The method according to claim 7, wherein The lightning arrester, power electronic device and mechanical switch are fixedly installed at the busbar outlet of the ring network circuit; When the ring network circuit is closed or opened, the measuring module and the control module are connected to the lightning arrester, the power electronic device and the mechanical switch as the moving parts.

13. The method according to claim 7, wherein When there is a switchgear at the busbar outlet of the ring network circuit, the lightning arrester, power electronic device, mechanical switch, measurement module and control module are installed at the busbar outlet of the ring network circuit as movable parts.

14. The method according to claim 1, wherein A ring network controller is installed between the busbar outlets on both sides of the ring network circuit and the first load corresponding to each.

15. The method according to claim 14, wherein The ring network controller is installed in the transformer substation or substation at the bus outlet, on the line between the bus outlet and the first ring network cabinet, on the low voltage side of the first box-type transformer after the bus outlet, or inside or next to the first ring network cabinet after the bus outlet.

16. The method according to claim 14, wherein When the ring network circuit is a single ring network, the ring network controller is installed at the two busbar outlets of the single ring network, and two ring network controllers are installed in the line of the single ring network connection; When the ring network circuit is a double ring network, the ring network controller is installed at the four busbar outlets of the double ring network, and a total of four ring network controllers are installed in the double ring network wiring line; When the ring network circuit is an N-supply and one-backup wiring distribution network, the ring network controller is installed at all busbar outlets of the N-supply and one-backup wiring distribution network, and a total of N+1 ring network controllers need to be installed in the N-supply and one-backup wiring line; When the ring network circuit is an N-1 wiring distribution network, the ring network controller is installed at all busbar outlets of the N-1 wiring distribution network, and a total of N ring network controllers need to be installed in the N-1 wiring line.

17. The method according to claim 1, wherein The determination of the active power reverse transmission includes: The instantaneous value of the current flowing through the ring network controller and the instantaneous value of the voltage near the load side or the bus side are collected through the measurement module; By calculating the angle between the voltage and current fundamental components, and determining the direction of active power according to the angle; If the active power is injected into the bus side, the active power is reversed; if the active power is injected into the load side, the active power is not reversed.

18. The method according to claim 1, wherein The control module controls the switch device to open according to the opening instruction, including: The control module controls the mechanical switch in the switch device to open according to the opening instruction, turns on the power electronic device in the switch device after a first set delay, and turns off the power electronic device after a second set delay; When the first set delay is reached, the mechanical switch has not yet started to open; When the second set delay is reached, the mechanical switch has been opened and the arc has been extinguished.

19. The method according to claim 1, wherein The control device controls the switching device to close and eliminate the breakpoint, bypass the lightning arrester, and restore the voltage of the ring network circuit based on the collected ring network circuit data, including: The instantaneous voltage difference between the two ends of the ring network controller is collected by a measurement module in the control device; If the instantaneous voltage difference between the two ends of the ring network controller is greater than a set threshold, a closing command is issued; The control module controls the switching device to close according to the closing instruction, so as to quickly restore the ring network circuit voltage; The time from the moment when the instantaneous voltage difference across the ring network controller is greater than the threshold to the moment when the switch is closed is within 10 ms.

20. The method according to claim 19, wherein The control module controls the switching device to close according to the closing instruction, including: The control module controls the triggering of the power electronic device and the closing of the mechanical switch according to the closing instruction, and cuts off the power electronic device after a third set delay; When the third set delay is reached, the mechanical switch completes closing and carries the load current.

21. The method according to claim 19, wherein The control module controls the switching device to close according to the closing instruction, and further includes: The control module controls the mechanical switch in the switch device to close.

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