Fast spare power automatic switching device and method suitable for high-proportion distributed power supply access

Abstract

The invention discloses a rapid spare power automatic switching device and method suitable for high-proportion distributed power supply access, and the device comprises a local sampling module which is used for collecting a local side bus voltage Ulocal and an incoming line current Ilocal; the switching value acquisition module is used for acquiring the TWJ state of the switch at the side; the communication module is used for communicating with an opposite-side remote transmission device through an HDLC protocol and acquiring opposite-side switch position information Kremote and an opposite-side voltage state Uremote; programmable logic is arranged in the logic processing module, and the logic processing module is used for executing comprehensive judgment logic; and the control output module is used for executing opening and closing operation of the switch according to the instruction of the logic processing module. Compared with a traditional spare power automatic switching technology, the method effectively solves the problems of operation refusal and maloperation caused by access of the high-proportion distributed power supply, and remarkably improves the power supply reliability and the new energy consumption capability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power system relay protection and control technology, in particular to a fast backup power automatic switching device and method suitable for high proportion of distributed power access. BACKGROUND

[0002] The backup power automatic switching device is a key safety automatic device on the distribution network side of the power system. Its core function is to quickly and reliably switch in the backup power supply when the main power supply loses voltage or fails, thereby ensuring the continuity of power supply and the reliable operation of regional load. In the traditional distribution network, the load is usually passive, and the power supply is unidirectional. The criterion design of the backup power automatic switching device is relatively simple, mainly relying on basic electrical quantities such as "no voltage and no current in the incoming line" and "no voltage in the bus" as the action conditions, and supplemented by logic such as "current blocking" as a false operation prevention measure. In the past few decades, it has been stable and reliable.

[0003] However, with the advancement of new power system construction, the penetration rate of distributed power sources represented by wind power and photovoltaic power in the distribution network is continuously increasing, and the system structure and its dynamic characteristics have changed fundamentally, posing a serious challenge to the logic adaptability of the traditional backup power automatic switching device, which is manifested in the following aspects: 1. The "current blocking" criterion is invalid when the PT line is broken, increasing the risk of backup power automatic switching misoperation. In the scenario of high proportion of distributed power access, local load may be consumed by distributed power on-site, resulting in a significant reduction in main incoming line current, even lower than the current set value of the traditional "current blocking". At this time, if the bus PT line is broken, the voltage measurement value is zero, but due to the small actual incoming line current, the current blocking condition cannot be met, and the backup power automatic switching device will misjudge that the bus has lost voltage, thus misoperating the backup power supply, causing non-synchronous closing, equipment impact and other serious consequences.

[0004] 2. Backup power automatic switching device refuses to operate or is severely delayed in the case of "steal jump" caused by distributed power supporting voltage. When the incoming line switch "steals jump" due to mechanical failure, etc., the main power supply has been disconnected, but the distributed power source still provides voltage support to the local bus through the inverter interface, forming an island operation state. The traditional backup power automatic switching device cannot start due to the detection of "bus voltage", and must wait for the island system to collapse due to power imbalance and the voltage to drop below the low voltage set value before it can operate. This process may take several seconds to several minutes, far exceeding the traditional action speed of hundreds of milliseconds, seriously affecting the power supply reliability of important loads.

[0005] Currently, some studies have attempted to partially optimize the traditional backup power automatic switching device by increasing voltage phase discrimination, adjusting fixed values and other ways, but the problems of missing multi-source information, insufficient criterion adaptability and rigid control logic have not been systematically solved. Therefore, a new backup power automatic switching device capable of fusing multi-source electrical quantities and state information of the local side and the opposite side and having an intelligent switching criterion is urgently needed to comprehensively improve its action reliability and response speed in the new power system. SUMMARY

[0006] In order to solve the problems of missing multi-source information, insufficient criterion adaptability and rigid control logic in the traditional backup power automatic switching device, the application provides a fast backup power automatic switching device and method suitable for high proportion of distributed power access, which effectively deals with the complex working conditions caused by high proportion of distributed power access through multi-source information fusion and configurable logic.

[0007] In order to achieve the above application purposes and solve the technical problems, the technical solutions adopted are as follows: The application discloses a fast backup power automatic switching device suitable for high proportion of distributed power access, which comprises: a local sampling module for collecting local bus voltage U local and incoming line current I local ; a switch quantity acquisition module for collecting TWJ state of the local switch; a communication module for communicating with the opposite side remote transmission device through a dedicated optical fiber to obtain opposite side switch position information K remote and opposite side voltage state U remote ; a logic processing module with programmable logic for executing comprehensive judgment logic; a control output module for executing switching on and off operation of the switch according to the instruction of the logic processing module.

[0008] The application further discloses a fast backup power automatic switching method suitable for high proportion of distributed power access, which uses the fast backup power automatic switching device to perform fast backup power automatic switching, and comprises the following steps: Step S1: collecting local electrical quantity information, including local bus voltage U local , local incoming line current I local analog quantity; Step S2: collecting local switch state information, including TWJ state of the local switch; Step S3: connecting the remote transmission device through a dedicated optical fiber communication channel to real-time receive opposite side switch position K remote and opposite side line voltage U remote , and then transmitting the real-time information to the backup power automatic switching device through the optical fiber; Step S4: According to the above multi-source information, combined with the configurable "bus voltage detection" control word CB_UV, the comprehensive judgment logic is executed to generate the backup power automatic switching action instruction.

[0009] Further, the embodiment of the step S1 is completed by a local sampling module. In the hardware configuration, the voltage of the local bus U local is collected by a voltage transformer, and the current of the local line I local is collected by a current transformer. The collected voltage and current signals are synchronously sampled by a 16-bit ADC at a sampling frequency of 1.2 kHz; in the software processing, the collected voltage and current signals are filtered, and then the fundamental effective value is calculated by using the full-cycle Fourier algorithm. Further, the embodiment of the step S2 is completed by a switching value acquisition module. In the hardware design, the TWJ state signal of the local switch is collected by a high-speed optocoupler isolation circuit; in the software processing, the TWJ state is monitored in real time, and the collected input signal is anti-jitter processed.

[0010] Further, the embodiment of the step S3 is to construct an information transmission link throughout the whole system. In the communication architecture design, the system adopts a layered transmission mode; a remote transmission device with a dedicated optical fiber interface is installed in the opposite side substation. The remote transmission device directly collects the state K remote and the line voltage U remote of the opposite side switch and performs local digital processing; thereafter, the collected data are transmitted to the backup power automatic switching device of the local station through a single-mode optical fiber link.

[0011] Further, in the step S4, the comprehensive judgment logic includes the line switch jump rapid judgment logic: When it is detected that the local TWJ=1 and |I local | <I set , the following judgment is performed: If there is no distributed power supply, the "bus voltage detection" control word CB_UV is put into, and then it is further judged whether the bus voltage U local < U set is established. If it is established, the backup power automatic switching action is performed after a short delay T1 to put the standby power supply into operation; If there is a distributed power supply, the control word CB_UV is exited, and then the backup power automatic switching action is directly performed after a short delay T2 to put the standby power supply into operation, wherein T2 < T1.

[0012] Further, in the step S4, the comprehensive judgment logic includes the bus PT disconnection blocking logic: When the bus voltage U local <U set and |I local | <I set are met, the PT disconnection discrimination is started. If the opposite side switch K remote =1 and the opposite side voltage U remote >U set , it is determined that the bus PT is broken, the backup power supply is immediately locked, and an alarm is issued. The mathematical criterion of the logic is: (U local <U set ) and (|I local |<I set ) and (K remote =1) and (U remote >U set )→Block_BZT. If the opposite side switch K remote =1 and the opposite side voltage U remote >U set , it is determined that a real fault enters the fault processing logic, and further backup power supply actions are performed.

[0013] Compared with the prior art, the present application has the following advantages and positive effects: 1. The present application introduces the opposite side switch position K remote and the opposite side line voltage U remote by using a multi-source information fusion criterion, and constructs a cross-verification closed-loop judgment logic. This enables the device to accurately distinguish between real faults and measurement abnormalities (such as PT broken lines) or "island false images" caused by distributed power generation, fundamentally avoiding misoperation caused by PT broken lines and refusal to operate caused by island pressure, and improving the action reliability of the backup power supply to a new level.

[0014] 2. The present application innovatively introduces a retractable "bus voltage detection" control word CB_UV. In the distributed power supply access scenario, by exiting the criterion and integrating the jump relay TWJ and the no-flow criterion, the fault can be quickly identified without waiting for the voltage to drop. This mechanism shortens the action decision time of the backup power supply from the traditional minute level to the second level, realizes a magnitude leap, and greatly guarantees the power supply continuity of important loads.

[0015] The present application integrates the opposite side switch state and voltage information into the decision through the remote device-special optical fiber-backup power supply structure, so that the backup power supply is upgraded from a single local control device to an intelligent terminal capable of sensing system topology and operating state. BRIEF DESCRIPTION OF DRAWINGS

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the framework of a fast backup automatic transfer device adapted to a high proportion of distributed power supply access according to the present invention. Figure 2 This is a schematic diagram of the backplane of a backup automatic transfer system adapted to a high proportion of distributed power supply access according to the present invention. Figure 3 This is a flowchart of a fast backup automatic transfer method adapted to a high proportion of distributed power supply access according to the present invention. Figure 4 This is a schematic diagram illustrating an application scenario of a backup automatic transfer system adapted to a high proportion of distributed power supply access according to the present invention. Figure 5 This invention provides a fast automatic transfer switch method for adapting to high proportion of distributed power supply access, which records the time from automatic transfer to tripping of the local switch under the condition of incoming switch tripping. Figure 6 The present invention provides a fast automatic transfer switch method for high-proportion distributed power supply access, which records the time from automatic transfer switch operation to connection of backup power supply under the condition of incoming switch tripping. Detailed Implementation

[0017] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figure 1 As shown, this embodiment discloses a fast automatic transfer switch (ATS) device adapted to a high proportion of distributed power supply access, comprising: The local sampling module is used to collect the local bus voltage U. local and incoming current I local ; The switch quantity acquisition module is used to acquire the TWJ status of the switch on this side; The communication module is used to communicate with the remote transmission device on the other side via a dedicated optical fiber to obtain the switch position information K on the other side. remote and the voltage state on the opposite side U remote ; The logic processing module has built-in programmable logic for executing comprehensive judgment logic; The control output module is used to execute the opening and closing operations of the switch according to the instructions of the logic processing module.

[0019] like Figure 2 The diagram shows a backplane schematic of a backup automatic transfer system adapted to a high proportion of distributed power sources, including a device for collecting the local bus voltage U. local and incoming current I local The local sampling module (AC quantity board) is used to communicate with the remote transmission device on the other side via a dedicated optical fiber to obtain the switch position information K on the other side. remote and the voltage state on the opposite side U remote The communication module (CPU board optical port); the logic processing module (CPU board core), with built-in programmable logic, is used to execute the comprehensive judgment logic; the control output module (output board) is used to execute the opening and closing operation of the switch according to the instructions of the logic processing module.

[0020] like Figure 3 As shown, this embodiment also discloses a fast backup automatic transfer method adapted to a high proportion of distributed power supply access. The fast backup automatic transfer device is used for fast backup automatic transfer, including the following steps: Step S1: Collect local electrical quantity information, including local bus voltage U local The incoming current I on this side local Analog quantity; Specifically, step S1 is implemented through a local sampling module. In terms of hardware configuration, a voltage transformer is used to collect the local bus voltage U. local The current transformer collects the incoming current I on this side. local The system uses a 16-bit ADC for synchronous sampling at a sampling frequency of 1.2kHz. In software processing, the acquired voltage and current signals are filtered, and then the fundamental RMS value is calculated using a full-cycle Fourier transform algorithm. This implementation ensures the accuracy and real-time performance of electrical quantity acquisition, providing a reliable data source for subsequent intelligent decision-making.

[0021] Step S2: Collect the status information of the local switch, including the TWJ status of the local switch; Specifically, step S2 is implemented through a switch quantity acquisition module. In terms of hardware design, a high-speed optocoupler isolation circuit is used to acquire the TWJ (trip relay) status signal of the local switch. In terms of software processing, the TWJ status is monitored in real time, and the acquired input signal is debouncing. This implementation effectively avoids misjudgments caused by a single relay failure or signal interference, ensuring accurate judgment of the incoming switch status.

[0022] Step S3: Connect to the remote transmission device via a dedicated fiber optic communication channel to receive the switch position K on the other side in real time. remote and the voltage U of the opposite lineremote The real-time information is then transmitted to the backup automatic transfer device via optical fiber. Specifically, step S3 is implemented by constructing an information transmission link that runs through the entire system. In terms of communication architecture design, the system adopts a layered transmission mode: a remote transmission device with a dedicated fiber optic interface is installed in the opposite substation, and this remote transmission device directly collects the status K of the opposite switch. remote and line voltage U remote The data is then digitized on-site. Subsequently, it is transmitted to the local backup automatic transfer device via a single-mode fiber optic link. This implementation method establishes a low-latency, highly reliable information channel, ensuring the real-time nature of critical status information from the other side and laying a solid foundation for subsequent multi-source information fusion and judgment.

[0023] Step S4: Based on the above multi-source information and combined with the configurable "busbar undervoltage check" control word CB_UV, execute the comprehensive judgment logic to generate the backup automatic transfer action command.

[0024] Specifically, in step S4, the comprehensive judgment logic includes a quick judgment logic for incoming line switch tripping: When it is detected that TWJ=1 (switch position) on this side and |I local | set When there is no current setpoint, perform the following judgment: If no distributed power source is connected, the "bus voltage check" control word CB_UV is activated, and the bus voltage U is further determined. local < U set If the (no-pressure setpoint) condition is met, the system will activate after a short delay of T1 and perform the automatic transfer switch to connect to the backup power supply. If a distributed power source is connected, the control word CB_UV exits, and the system directly activates after a short delay T2, performing an automatic transfer switch to connect the backup power source. T2... <T1。

[0025] Furthermore, in step S4, the comprehensive judgment logic includes busbar PT disconnection blocking logic: When the bus voltage U is satisfied local set And|I local | set When this happens, the PT disconnection detection is initiated; If the opposite switch K is satisfied at the same time remote =1 (switch closed) and the voltage U on the opposite side remote >U set If the busbar PT is disconnected, the automatic transfer switch will be immediately blocked and an alarm will be issued. The mathematical criterion for this logic is: (U local set )∧(|I local | <I​​​​set )∧(K remote =1)∧(U remote >U set → Block_BZT; If the opposite switch K cannot be satisfied simultaneously remote =1 (switch closed) and the voltage U on the opposite side remote >U set If the fault is identified as a real fault, the fault handling logic will be entered, and the automatic transfer switch will be executed to activate the backup power supply.

[0026] Example To verify the fast backup automatic transfer method for high-proportion distributed power generation proposed in this invention, a detailed explanation is provided below using a real-world case study of a 110kV substation in Yichun, Jiangxi Province, with a high proportion of distributed photovoltaic power generation. The main wiring diagram of this substation is shown below. Figure 4 As shown, the original configuration of the traditional automatic transfer switch has a significant risk of islanded operation due to the large number of distributed hydropower and photovoltaic systems connected to the station and feeder side. There have been multiple incidents where the automatic transfer switch failed to operate because the bus voltage was supported by the hydropower inverter after the incoming line switch was tripped.

[0027] Application Scenario and Problem Description: This 110kV substation adopts a single busbar segmented connection configuration, receiving power through two 110kV incoming lines (L1, L2) and supplying power to the load area through multiple 10kV feeders. Simultaneously, approximately 50MW of distributed hydropower is connected to the 10kV busbar. Before applying this invention, when the main incoming line L1 tripped due to a mechanical failure, the 10kV busbar within the substation maintained normal voltage due to the support of the photovoltaic power source. The traditional automatic transfer switch remained locked due to continuous detection of "voltage on the busbar," preventing automatic activation of the backup incoming line L2. This resulted in the entire substation being powered solely by the photovoltaic island system. Due to severe power imbalance, this island system typically collapsed within 1-2 minutes due to voltage or frequency failure, causing a substation-wide power outage with a power restoration time of several minutes.

[0028] Implementation and configuration of the device of the present invention: To solve the above problems, the automatic transfer switch device of the present invention was applied in this substation. Specifically, the device of the present invention was installed in the substation and a communication connection was established with the remote transmission devices of two 110kV power supply points on the opposite side through an HDLC optical fiber channel to obtain the real-time switch position K on the opposite side. remote1 K remote2 and the voltage U of the opposite line remote1 U remote2 Given the high proportion of hydropower and photovoltaic power connected to this station, the critical "busbar undervoltage check" control word CB_UV is set to "0" (exit status).

[0029] Action Process and Analysis: In a simulation test, the main power supply line L1 switch experienced a simulated accidental tripping. The logic judgment and action sequence of the device of this invention are as follows: 1) S1 & S2: The device immediately detects TWJ_L1=1 (L1 switch is in position) and |I local_L1 | set (No current in L1 input). 2) S3: Confirm the opposite switch K via HDLC channel. remote1 =1 (combined position), but U remote1 > U set (Voltage is normal), which rules out the possibility of a power outage on the other side. 3) S4: Since CB_UV=0, the device skips the "busbar undervoltage check" criterion, such as Figure 5 As shown, the switch on this side trips after two cycles (40ms). 4) After the switch on this side trips, the device immediately issues a closing command, and after a closing delay of T2=100ms (user-configurable), the backup incoming line L2 is successfully connected. Figure 6 As shown, the entire process from the switch tripping to the backup power supply being activated takes only about 140ms.

[0030] PT disconnection interlocking logic verification: To fully verify the anti-maloperation performance of this invention, a busbar PT disconnection fault was simulated within the station. When the device detects U... local set And|I local | set At that moment, instead of immediately identifying it as a busbar undervoltage, the device activated the PT disconnection detection logic. The device confirmed the status of the opposite switch K via a dedicated fiber optic channel. remote =1 (closed position) and the voltage U on the opposite side remote >U set (Voltage is normal), based on this comprehensive judgment, it is determined that the PT measurement circuit on this side is abnormal, rather than a real voltage loss. The device immediately executes the interlock (Block_BZT=1) and accurately issues a "PT disconnection" alarm signal, effectively avoiding the malfunction of traditional automatic transfer switch in this scenario. This embodiment fully demonstrates that the method described in this invention, through the fusion of the same set of multi-source information criteria, can not only effectively identify the "voltage illusion" created by distributed power sources and shorten the automatic transfer switch (ATS) operation time from minutes to milliseconds in the case of incoming switch tripping, but also accurately distinguish between actual bus voltage loss and PT measurement circuit anomalies, reliably blocking PT disconnection to prevent false tripping. This invention systematically solves the core contradiction of "failure to operate" and "false operation" faced by ATS under high-proportion distributed power source access, fundamentally improving power supply reliability.

[0031] ​​​Those skilled in the art should understand that although this invention uses a typical 110kV substation with a high proportion of distributed power supply access as an example to design and describe an automatic transfer switch (ATS) device, the core principles of the method and device, including the comprehensive criterion for multi-source information fusion based on a dedicated optical fiber channel connecting a remote transmission device, the "no voltage on the busbar" control word logic that can be switched on or off, and the collaborative verification mechanism for the position of the opposite switch and the line voltage information, are applicable to distribution network scenarios with other voltage levels, different main wiring configurations, and distributed power supply types. Any method consistent with the technical concept of this invention—that is, introducing a remote transmission device into the ATS device and obtaining information from the opposite side through a dedicated optical fiber or other equivalent communication means to constitute a multi-source fusion criterion—or any modifications, equivalent substitutions, or improvements made to the communication method, criterion logic, or hardware platform based thereon, should be included within the scope of protection of this invention.

[0032] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A fast automatic transfer switch device adapted to a high proportion of distributed power sources, characterized in that, include: The local sampling module is used to collect the local bus voltage U. local and incoming current I local ; The switch quantity acquisition module is used to acquire the TWJ status of the switch on this side; The communication module is used to communicate with the remote transmission device on the other side via a dedicated optical fiber to obtain the switch position information K on the other side. remote and the voltage state on the opposite side U remote ; The logic processing module has built-in programmable logic for executing comprehensive judgment logic; The control output module is used to execute the opening and closing operations of the switch according to the instructions of the logic processing module.

2. A fast backup automatic transfer method adapted to a high proportion of distributed power source access, characterized in that, Using the fast automatic transfer switch as described in claim 1 to perform fast automatic transfer includes the following steps: Step S1: Collect local electrical quantity information, including local bus voltage U local The incoming current I on this side local Analog quantity; Step S2: Collect the status information of the local switch, including the TWJ status of the local switch; Step S3: Connect to the remote transmission device via a dedicated fiber optic communication channel to receive the switch position K on the other side in real time. remote and the voltage U of the opposite line remote The real-time information is then transmitted to the backup automatic transfer device via optical fiber. Step S4: Based on the above multi-source information and combined with the configurable "busbar undervoltage check" control word CB_UV, execute the comprehensive judgment logic to generate the backup automatic transfer action command.

3. The fast backup automatic transfer method for adapting to a high proportion of distributed power source access according to claim 2, characterized in that, The implementation of step S1 is accomplished through a local sampling module. In terms of hardware configuration, a voltage transformer is used to collect the local bus voltage U. local The current transformer collects the incoming current I on this side. local Synchronous sampling is performed by a 16-bit ADC at a sampling frequency of 1.2kHz; In terms of software processing, the acquired voltage and current signals are filtered, and then the full-cycle Fourier algorithm is applied to calculate the fundamental effective value.

4. The fast backup automatic transfer method for adapting to a high proportion of distributed power supply access according to claim 2, characterized in that, The implementation of step S2 is accomplished through a switch quantity acquisition module. In terms of hardware design, a high-speed optocoupler isolation circuit is used to acquire the TWJ status signal of the local switch. In terms of software processing, the TWJ status is monitored in real time and the acquired input signal is de-jittered.

5. A fast backup automatic transfer method adapted to high proportion of distributed power source access according to claim 2, characterized in that, The implementation of step S3 involves constructing an information transmission link that runs through the entire system. In terms of communication architecture design, the system adopts a layered transmission mode. A remote transmission device with a dedicated fiber optic interface is installed at the opposite substation. This remote transmission device directly collects the status K of the opposite switch. remote and line voltage U remote The data is then processed digitally on-site and transmitted to the local backup automatic transfer device via a single-mode fiber optic link.

6. A fast backup automatic transfer method adapted to high proportion of distributed power source access according to claim 2, characterized in that, In step S4, the comprehensive judgment logic includes a fast judgment logic for incoming line switch tripping: When it is detected that TWJ=1 on this side and |I local | set When this happens, the following judgment is performed:​ If no distributed power source is connected, the "bus voltage check" control word CB_UV is activated, and the bus voltage U is further determined. local < U set If the condition is met, the action will be performed after a short delay of T1, and the backup power supply will be automatically switched on. If a distributed power source is connected, the control word CB_UV exits, and the system directly activates after a short delay T2, performing an automatic transfer switch to connect the backup power source. T2... <T1。 7. A fast backup automatic transfer method for adapting to a high proportion of distributed power source access according to claim 2, characterized in that, In step S4, the comprehensive judgment logic includes the busbar PT disconnection blocking logic: When the bus voltage U is satisfied local set And|I local | set When this happens, the PT disconnection detection is initiated;​​ If the opposite switch K is satisfied at the same time remote =1 and the voltage on the opposite side U remote >U set If the busbar PT is disconnected, the automatic transfer switch will be immediately blocked and an alarm will be issued. The mathematical criterion for this logic is: (U local set )∧(|I local | set )∧(K remote =1)∧(U remote >U set → Block_BZT;​​ If the opposite switch K cannot be satisfied simultaneously remote =1 and the voltage on the opposite side U remote >U set If the fault is identified as a real fault, the fault handling logic will be entered, and the automatic transfer switch will be executed to activate the backup power supply.

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