Method and apparatus for eliminating the risk of over-regulation in a voltage step control procedure

Abstract

This invention discloses a method and apparatus for eliminating the risk of over-regulation in the voltage graded control process, which relates to the field of power system distribution network automation control technology. By constructing master-slave collaborative control logic and a one-way command transmission mechanism, and performing tap position resetting, time delay locking and secondary voltage regulation on slave voltage regulating equipment, the risk of over-regulation in distribution network voltage graded control is eliminated and the stability of voltage control is improved.

Description

Technical Field

[0001] This invention relates to the field of power system distribution network automation control technology, and in particular to a method and apparatus for eliminating the risk of over-regulation in the voltage grading control process. Background Technology

[0002] With the explosive growth of installed capacity from distributed renewable energy sources such as wind and solar power, voltage fluctuations have become a significant issue for distribution lines with long power supply radii. Utilizing multiple voltage regulators for global voltage control of 10kV distribution lines is an effective way to mitigate the impact of renewable energy and improve power quality. In distribution networks with distributed power sources, multiple voltage regulators are often connected in series to achieve graded voltage control. However, relying solely on local control of the voltage regulators can lead to over-regulation. Due to fluctuations in distributed power output or changes in power flow direction, voltage regulators may experience over-regulation due to inconsistent switching of regulation modes, resulting in issues such as low or high voltage. Traditional methods, relying on local control strategies of the voltage regulators, struggle to coordinate actions during power flow changes, easily leading to voltage instability or regulation conflicts. While communication-based coordination schemes exist, they are typically complex, costly, and difficult to adapt to changing distribution network operating conditions. In particular, when the downstream voltage regulator in the slave position lacks an autonomous correction mechanism, the voltage on the downstream voltage regulator side may exceed the limit due to the superposition of the dual regulation under the condition of changing power flow direction, which in turn leads to excessively high or low voltage, affecting the reliability of power supply.

[0003] like Figure 2 As shown, when the distributed power generation output is low, the power flow through voltage regulator 2 reverses, but not enough to reverse the entire power flow. The power flow through voltage regulator 1 remains positive. Under this condition, voltage regulator 2 will downshift according to the power flow direction, while voltage regulator 1 will upshift according to the power flow direction. If the distributed power generation output continues to increase under the above condition, or if distributed power sources between the two voltage regulators start up successively, the power flow through voltage regulator 1 changes from positive to negative, and the regulation mode of voltage regulator 1 changes from upshifting to downshifting. Since the power flow direction through voltage regulator 2 has not changed, it maintains its original position. The larger voltage side of voltage regulator 2 is essentially affected by the double effect of downshifting from both voltage regulators, resulting in a lower voltage on the larger voltage side of voltage regulator 2. Conversely, if... Figure 3 As shown, even when the power flow is positive, high voltage may occur on the second large side of the voltage regulator due to the superimposed effect of the voltage regulator's upshifting. The essence of the problem is that in the distribution network voltage level control process, the downstream voltage regulator, which is in a slave position, lacks a mechanism for autonomously correcting its upshift. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies where multiple voltage regulators in series-connected hierarchical control rely solely on local independent regulation, lack a master-slave collaborative mechanism, and are prone to over-regulation due to power flow changes and superimposed regulation actions. This invention provides a method and apparatus for eliminating the risk of over-regulation in the voltage hierarchical control process. By constructing master-slave collaborative control logic and a one-way command transmission mechanism, and performing level resetting, time delay locking, and secondary voltage regulation on the slave voltage regulators, the risk of over-regulation in distribution network voltage hierarchical control is eliminated and the stability of voltage control is improved.

[0005] The objective of this invention is achieved through the following technical solution: Methods for eliminating over-regulation risk in voltage graded control processes include: A master-slave collaborative control logic is configured for voltage regulating equipment deployed in series in power distribution lines, so that the voltage regulating equipment is divided into master voltage regulating equipment and slave voltage regulating equipment, and a one-way command transmission path is established between the master voltage regulating equipment and the slave voltage regulating equipment. When the master voltage regulating equipment performs iterative adjustment of the tap level in response to the switching of power flow direction in the distribution network or the output disturbance of distributed power sources, it sends a voltage regulating action trigger command to the slave voltage regulating equipment through the one-way command transmission path. After receiving the voltage regulating action trigger command, the slave voltage regulating equipment forces its own tap level back to the preset reference tap level and enters a time delay lock state that matches the full tap level adjustment time of the master voltage regulating equipment. After the time delay lock period expires, the slave voltage regulating equipment performs secondary tap level adjustment based on the real-time node voltage deviation and the preset voltage regulation target.

[0006] Preferably, the voltage regulating device is a multi-stage series voltage regulating device of no less than three units, including one master voltage regulating device and at least two slave voltage regulating devices; the master voltage regulating device and each slave voltage regulating device form a one-to-many broadcast unidirectional command transmission architecture or a chain recursive unidirectional command transmission architecture.

[0007] Preferably, the duration of the time delay lock state is determined by the product of the single-gear operation interval of the main voltage regulator and the total number of adjustable gears.

[0008] Preferably, the duration of the time delay lock state is not less than the maximum time required for the main voltage regulator to complete the full range gear adjustment.

[0009] As a preferred embodiment, when the main voltage regulator and each slave voltage regulator form a chain-recursive unidirectional command transmission architecture, the duration of the delay lock state of the downstream slave voltage regulator is dynamically shortened based on the duration of the delay lock state already completed by the upstream slave voltage regulator; the magnitude of the dynamic shortening is adaptively determined by combining the power grid operation model with real-time power flow and voltage conditions.

[0010] Preferably, the magnitude of the dynamic reduction is adaptively determined by combining a power grid operation model with real-time power flow and voltage conditions, specifically: The power grid operation model collects the actual adjustment time of the upstream voltage regulating equipment in real time, and compares the actual adjustment time with the preset maximum delay lock time. If the absolute value of the difference between the actual adjustment time of the upstream voltage regulator and the preset maximum delay lock-in time is greater than the set adjustment threshold, then based on the actual adjustment time and combined with the downstream voltage regulator's own adjustment parameters, current voltage deviation and power flow conditions, the initial delay lock-in time of the downstream voltage regulator is dynamically shortened and corrected to determine the optimal delay lock-in time that is suitable for the current operating conditions.

[0011] Preferably, the voltage regulating device is at least two feeder voltage regulating devices, with the main voltage regulating device and the slave voltage regulating device arranged sequentially along the power transmission direction of the feeder.

[0012] Preferably, the one-way command transmission path adopts a wired carrier or wireless private network communication mode, and the frame structure sent by the one-way command transmission path only includes voltage regulation action trigger identifier and device identification code information.

[0013] A device for eliminating the risk of over-regulation in a voltage grading control process includes: Master-slave configuration module, one-way communication module, gear reset module, delay lock module, and secondary voltage regulation module; The master-slave configuration module is used to configure master-slave collaborative control logic for voltage regulating devices deployed in series in power distribution lines, and to divide the voltage regulating devices into master voltage regulating devices and slave voltage regulating devices. The one-way communication module is used to establish a one-way command transmission path between the main voltage regulator and the slave voltage regulator to transmit voltage regulation action trigger commands. The gear reset module is used to forcibly reset its own gear to a preset reference gear after receiving a pressure regulation action trigger command from the pressure regulating device. The time delay locking module is used to control the voltage regulating device to enter a time delay locking state that matches the full range adjustment time of the main voltage regulating device; The secondary voltage regulation module is used to control the voltage regulation device to perform secondary gear adjustment based on the real-time node voltage deviation and the preset voltage regulation target after the time delay lock period expires. The main voltage regulating device is configured to perform iterative adjustment of the voltage level in response to the switching of power flow direction in the distribution network or the disturbance of the output of distributed power sources, and to trigger the one-way communication module to send a voltage regulation action trigger command.

[0014] Preferably, the voltage regulating device is a multi-stage series voltage regulating device of no less than three units, including one main voltage regulating device and at least two slave voltage regulating devices; The one-way communication module is configured to support a one-to-many broadcast one-way command transmission architecture or a chain-recursive one-way command transmission architecture.

[0015] The beneficial effects of this invention are as follows: By establishing a unidirectional command transmission path between the master voltage regulator and the slave voltage regulator, and configuring master-slave collaborative control logic, this invention enables the slave voltage regulator to immediately receive a trigger command and force a return to the preset reference level when the master voltage regulator performs a gear adjustment due to power flow direction switching or distributed power output disturbances, and then enters a time-delayed locking state. This mechanism achieves coordination between voltage regulators through low-cost unidirectional communication, and its structure is simple and easy to implement.

[0016] By employing a time-delay locking design, the slave voltage regulator ensures that it performs secondary regulation based on real-time voltage deviation only after the master voltage regulator has completed all regulation actions and is operating stably. This effectively avoids voltage over-regulation caused by timing conflicts between the master and slave voltage regulators or the superposition of dual regulation, significantly improving the voltage stability of the distribution network and adapting to the complex operating conditions after the integration of distributed power sources. Furthermore, the time-delay locking duration can be flexibly configured or dynamically adjusted according to the voltage regulator's operating characteristics, enhancing the method's versatility and adaptability to different operating conditions. Attached Figure Description

[0017] Figure 1 This is a flowchart of the present invention; Figure 2 This is a schematic diagram of the operating conditions of voltage regulating equipment in the prior art; Figure 3 This is a schematic diagram of another operating condition for voltage regulating equipment in existing technology. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Example: Example 1: As Figure 1 As shown, this embodiment provides a method for eliminating the risk of over-regulation in the voltage grading control process. This method addresses the voltage over-regulation problem caused by sudden changes in power flow direction or fluctuations in distributed generation output when multiple voltage regulating devices are connected in series in a distribution network. It proposes a control strategy based on master-slave collaboration and time-series isolation.

[0020] Specifically, the method in this embodiment includes the following steps: Step S100 involves configuring master-slave collaborative control logic for the voltage regulating devices deployed in series in the power distribution line, thus classifying the voltage regulating devices into master and slave voltage regulating devices, and establishing a unidirectional command transmission path between them. In this step, the master-slave roles are not fixed but can be flexibly configured according to the line topology or control strategy requirements. For example, voltage regulating devices located on the power supply side or at key nodes can be designated as master voltage regulating devices, responsible for responding to system-level disturbances; while downstream or end-point voltage regulating devices can be designated as slave voltage regulating devices. The unidirectional command transmission path only allows signals to flow from the master voltage regulating device to the slave voltage regulating device, a design significantly different from existing bidirectional interactive communication architectures. The unidirectional transmission path eliminates the need for complex handshake protocols and response mechanisms, not only greatly reducing the hardware cost of the communication module but also avoiding the risk of control deadlock due to communication blockage or lost responses, thereby ensuring the reliability and real-time performance of the control system at the source.

[0021] Step S200: When the main voltage regulator performs a level iterative adjustment in response to the switching of power flow direction in the distribution network or the disturbance of the output of distributed power sources, it sends a voltage regulation action trigger command to the slave voltage regulator through the one-way command transmission path.

[0022] This step establishes a triggering mechanism of "master equipment acts first, slave equipment responds." When the power flow direction in the distribution network reverses (e.g., from forward to reverse) or the output of distributed power sources fluctuates significantly, the main voltage regulator first detects the voltage deviation and initiates the voltage adjustment logic. Simultaneously with the main voltage regulator performing the upshift or downshift action, it sends a trigger command through a unidirectional path. This command serves only as an "action signal" and does not contain specific adjustment range or target voltage information, further reducing the impact of communication errors on control accuracy.

[0023] In step S300, after receiving the pressure regulation action trigger command, the pressure regulating device forcibly resets its own gear to the preset reference gear and enters a time delay lock state that matches the full gear adjustment time of the main pressure regulating device.

[0024] This is the core step in this embodiment to eliminate the risk of over-adjustment. The forced resetting to the preset reference level (e.g., the 5th level in the middle range) aims to eliminate the accumulated deviation of the voltage regulator that may have existed in the previous steady state. If the resetting is not performed, when the main voltage regulator operates and causes a change in the line voltage distribution, the original level of the secondary voltage regulator may no longer be suitable for the new power flow conditions, and direct adjustment based on the current level is very likely to cause overshoot. Through forced resetting, the secondary voltage regulator is equivalent to entering a known and safe initial state, leaving sufficient adjustment space for subsequent adjustments.

[0025] Simultaneously, the slave voltage regulator enters a time-delay lockout state. The duration of this lockout is set to be no less than the maximum time required for the master voltage regulator to complete full-range adjustment. For example, if the master voltage regulator's single-range action interval is 2 minutes and the total number of adjustable ranges is 9, the maximum full-range adjustment time is approximately 18 minutes. Therefore, the lockout duration can be set to 18 minutes or slightly longer. During this period, the slave voltage regulator locks its automatic voltage regulation logic and remains stationary. This physical time isolation mechanism ensures that the master voltage regulator can complete all its adjustment actions without interference, avoiding the superposition of adjustment effects caused by simultaneous actions of the master and slave devices, thus fundamentally cutting off the over-adjustment path caused by "dual adjustment superposition."

[0026] In step S400, after the time delay lockout period expires, the voltage regulating device performs a secondary gear adjustment based on the real-time node voltage deviation and the preset voltage regulation target.

[0027] After the delay lockout period ends, the main voltage regulator has completed its adjustment and entered a steady state, and the power flow distribution on the line has stabilized. At this point, the slave voltage regulator is unlocked, and the real-time node voltage at its installation point is re-acquired, and the deviation from the target voltage is calculated. Based on this real-time deviation, the slave voltage regulator performs a secondary adjustment. Since the system has eliminated the dynamic disturbances during the main equipment's operation, the slave voltage regulator's adjustment action is based on steady-state conditions, thus accurately maintaining the node voltage within the acceptable range and effectively avoiding the risk of over-regulation.

[0028] Through the above steps, this embodiment achieves inter-device collaboration using low-cost one-way communication, eliminates accumulated errors through forced resetting, and achieves physical isolation of adjustment timing using delay locking, ultimately realizing effective suppression of the risk of voltage over-regulation under complex operating conditions.

[0029] Example 2: This embodiment, based on embodiment 1, further elaborates on the deployment architecture and communication implementation details of the voltage regulating device.

[0030] The voltage regulating device is a multi-stage series voltage regulating device of no less than three units, including one master voltage regulating device and at least two slave voltage regulating devices. In this multi-stage series scenario, the master voltage regulating device and each slave voltage regulating device form a one-to-many broadcast unidirectional command transmission architecture or a chain-recursive unidirectional command transmission architecture.

[0031] Specifically, the one-to-many broadcast unidirectional command transmission architecture is suitable for radial or low-branch power distribution topologies. In this architecture, the master voltage regulator acts as the sole command source node, simultaneously sending trigger commands to all downstream slave voltage regulators via a single communication channel. The advantage of this architecture lies in its extremely simple communication logic, eliminating the need for complex routing and addressing. All slave devices receive and execute reset and locking logic indiscriminately, significantly reducing system deployment costs. The chain-recursive unidirectional command transmission architecture, on the other hand, is more suitable for long-line scenarios with extremely long power supply radii and numerous cascaded voltage regulators. In this architecture, the master voltage regulator sends commands to the first-level slave voltage regulators. After completing its own action logic, the first-level slave voltage regulator can act as a relay node or, according to preset logic, transmit trigger commands to the next-level slave voltage regulator. This architecture can adapt to signal attenuation issues in long-distance communication and allows for more refined timing control of devices at each level based on upstream conditions.

[0032] Furthermore, the voltage regulating equipment specifically comprises at least two feeder voltage regulating devices, with the main voltage regulating device and the slave voltage regulating device arranged sequentially along the power transmission direction of the feeder. The feeder voltage regulating devices are typically installed directly on the poles or in the switching stations of the 10kV distribution lines, with their input and output terminals directly connected in series in the main feeder line, unlike the main transformer voltage regulating devices installed in substations. This arrangement allows the voltage regulating devices to directly respond to voltage fluctuations in the middle section of the line. Especially when the distributed power supply connection point is located between two feeder voltage regulating devices, the upstream main voltage regulating device and the downstream slave voltage regulating device can effectively mitigate voltage over-limits caused by power flow reversal through the collaborative logic described in this invention.

[0033] At the communication implementation level, the one-way command transmission path adopts either wired carrier or wireless private network communication modes. Wired carrier communication can utilize existing 10kV power distribution lines as the transmission medium, eliminating the need for additional fiber optic cables. It transmits high-frequency signals superimposed on the power frequency current via a coupling device, making it ideal for overhead line environments. Wireless private network communication can use dedicated power-specific wireless frequency bands such as LTE-G and LoRa, suitable for areas with complex terrain or where line modifications are difficult. Regardless of the physical medium used, the frame structure transmitted by the one-way command transmission path only contains the voltage regulation action trigger identifier and device identification code information.

[0034] As a specific encoding example, this frame structure can be designed as a fixed-length 8-byte binary data packet. The first byte is the frame header identifier, fixed at "0xAA", used to wake up the demodulation circuit at the receiving end; bytes 2 to 5 are device identification codes, for example, set to the unique ID number of the main voltage regulator "0x010x020x030x04", used to verify the legitimacy of the command source from the voltage regulator, preventing the accidental reception of interference signals from other line devices; the sixth byte is the voltage regulation action trigger identifier, for example, "0x55" represents a gear adjustment trigger, and "0x66" represents a reset trigger; in this embodiment, the main voltage regulator sends "0x55" when it takes action; the seventh byte is the checksum, used by the receiving end to perform data integrity verification; the eighth byte is the frame tail identifier, fixed at "0x55". This simplified frame structure design minimizes the data volume, not only reducing the requirements for communication bandwidth but also significantly improving the real-time performance and anti-interference capability of command transmission, ensuring that the slave voltage regulator can accurately parse the command and trigger the forced reset logic within milliseconds.

[0035] Example 3: This embodiment, based on the above embodiment, further details the mechanism for determining the duration of the "delay lockout state". Accurate setting of the delay lockout duration is a key parameter for balancing regulation response speed and avoiding over-regulation risks. If the duration is set too short, the slave voltage regulator may be triggered before the main voltage regulator has stabilized, potentially causing regulation conflicts. If the duration is set too long, the voltage deviation will persist for too long, affecting power quality.

[0036] To address the aforementioned issues, this embodiment first provides a static calculation method based on device parameters. The duration of the time-delay lock state is determined by the product of the single-gear operation interval of the main voltage regulator and the total number of adjustable gears. Specifically, assuming the single-gear operation interval of the main voltage regulator is T_step (unit: seconds) and its total number of adjustable gears is N, the time-delay lock duration T_lock can be calculated as T_lock = T_step × N. For example, if the single-gear operation interval of a feeder voltage regulator is 60 seconds and the total number of gears is 9, the calculated time-delay lock duration is 540 seconds. Furthermore, to address uncertainties such as the action delay of the mechanical transmission mechanism or communication jitter, the duration of the time-delay lock state should not be less than the maximum time required for the main voltage regulator to complete the full-range gear adjustment. In actual deployment, a safety margin coefficient (e.g., 1.1 times) can be added to the above calculated value to ensure that the adjustment process of the main voltage regulator is completely covered within the lock cycle of the slave voltage regulator, regardless of the operating conditions.

[0037] As a more optimized implementation, when the main voltage regulator and each slave voltage regulator form a chain-recursive unidirectional command transmission architecture, if all slave voltage regulators at all levels adopt a uniform fixed-duration lockout, the waiting time for downstream devices will be longer, resulting in a slower overall system response speed. Therefore, the duration of the delay lockout state of downstream slave voltage regulators can be dynamically shortened based on the duration of the delay lockout state already completed by upstream slave voltage regulators; the magnitude of this dynamic shortening is adaptively determined by the power grid operation model in conjunction with real-time power flow and voltage conditions.

[0038] Specifically, the magnitude of the dynamic reduction is adaptively determined by combining the power grid operation model with real-time power flow and voltage conditions, and is implemented through the following logical steps: Step S501, Data Acquisition and Input. The power grid operation model acquires the actual tap adjustment time T_actual of the upstream voltage regulator in real time. This time refers to the period from the moment the upstream voltage regulator unlocks until it completes the second tap adjustment and reaches a steady state. At the same time, the model reads the preset maximum delay lockout time T_max (i.e., the aforementioned static calculation value) and the set adjustment threshold ΔT_th.

[0039] Step S502, State Comparison and Judgment. The model compares the actual adjustment duration T_actual with the preset maximum delay lock duration T_max. The absolute value of the difference between the two, |T_max - T_actual|, is calculated. If the absolute value of this difference is greater than the set adjustment threshold ΔT_th, it is determined that the actual gear change amplitude of the upstream device is consistently small, therefore the predicted actual gear change amplitude of the downstream device is also small, and it is not necessary to maintain the maximum delay lock duration. In this case, the dynamic correction process for the downstream device's delay duration is triggered. If the difference is less than or equal to the threshold, the initial preset duration of the downstream device remains unchanged.

[0040] Step S503, Dynamic Correction Calculation. If correction is triggered, based on the actual adjustment time T_actual and combined with the downstream voltage regulator's own adjustment parameters, current voltage deviation, and power flow conditions, the initial delay lock-in time of the downstream voltage regulator is dynamically shortened to determine the optimal delay lock-in time suitable for the current operating conditions. The specific correction algorithm can adopt the following logic: First, the time margin ΔT = T_max - T_actual is calculated. This margin represents the time saved by upstream equipment completing adjustments ahead of schedule. Then, a correction factor K is introduced, the value of which is related to the current voltage deviation ΔU and the power flow condition P_flow. For example, when the voltage deviation is large, K is smaller (e.g., 0.5-0.7), meaning the reduction is limited to allow for more safe observation time; when the power flow is stable and the voltage deviation is small, K is larger (e.g., 0.8-1.0), allowing for a larger reduction to improve response speed.

[0041] Finally, the formula for calculating the downstream correction delay lock-in time T_lock_new from the voltage regulator is: T_lock_new = T_lock_initial - K × ΔT Among them, T_lock_initial is the initial preset duration of the downstream device.

[0042] Through the above mechanism, the system can adaptively adjust the waiting time of the downstream equipment according to the actual operation of the upstream equipment. For example, if the upstream equipment only needs to adjust by one level to reach steady state due to small voltage deviation, its actual time is much less than the maximum duration. In this case, the downstream equipment can significantly reduce the invalid waiting time by dynamically shortening the logic, thereby significantly improving the overall response speed and voltage management efficiency of the multi-stage series voltage regulation system without introducing the risk of over-regulation.

[0043] Example 4: This embodiment provides a device for eliminating the risk of over-regulation in the voltage grading control process. The device is applied to a power distribution line containing multiple series voltage regulating devices. Through the coordinated design of hardware and logic, the method flow described in embodiments 1 to 3 is specifically implemented.

[0044] Specifically, the device includes a master-slave configuration module, a one-way communication module, a gear reset module, a time delay lock module, and a secondary voltage regulation module. These modules are connected via an internal bus or signal lines to collaboratively complete the voltage regulation task.

[0045] The master-slave configuration module is used to configure master-slave collaborative control logic for voltage regulating devices deployed in series in power distribution lines, classifying the voltage regulating devices into master and slave voltage regulating devices. Specifically, this module can consist of an embedded processor and its internally stored control strategy program. In actual deployment, maintenance personnel can input device role information through a human-machine interface or remote configuration interface. The master-slave configuration module reads this information and sets the working mode of the device. If set as a master voltage regulating device, the module activates the active regulation logic of the device; if set as a slave voltage regulating device, it activates the passive response logic. It should be understood that this role division is at the logical level. The same hardware device can flexibly switch roles in different line topologies through configuration, thereby enhancing the versatility and field adaptability of the device.

[0046] The unidirectional communication module is used to establish a unidirectional command transmission path between the master voltage regulator and the slave voltage regulator to transmit voltage regulation action trigger commands. This is one of the core hardware features of the device in this embodiment. Physically, the unidirectional communication module includes at least a transmitter, a receiver, and a communication channel connecting the two. For the master voltage regulator, only the transmitter circuit is integrated or enabled internally; for the slave voltage regulator, only the receiver circuit is integrated or enabled internally. This asymmetric hardware design physically eliminates the possibility of the slave voltage regulator sending interference signals to the master voltage regulator, greatly simplifying the design complexity of the communication protocol stack. For example, the transmitter can be a low-power wireless radio frequency transmitting unit or a power line carrier coupled transmitting circuit; the receiver corresponds to a wireless receiving unit or a carrier demodulation circuit. The communication channel can be a private wireless network frequency band or a power distribution line conductor. This unidirectional isolation at the physical layer ensures low cost and high reliability of control command transmission.

[0047] The gear reset module is used to forcibly reset its gear to a preset reference gear after receiving a voltage regulation action trigger command from the voltage regulating equipment. This module typically consists of the voltage regulating equipment's controller (such as a DSP or MCU) and its drive circuitry. When the receiving end parses a valid trigger command, the gear reset module immediately interrupts the current holding state and controls the motor mechanism of the on-load tap changer to drive the gear to a preset intermediate gear (such as gear 5). This process does not require complex voltage sampling calculations and is a protective hardware preset action designed to quickly eliminate accumulated errors.

[0048] The time-delay locking module is used to control the slave voltage regulator to enter a time-delay locking state that matches the full-range adjustment time of the master voltage regulator. This module can be implemented in hardware as a timer circuit or a timing logic unit within the controller. After the range reset action is completed, the time-delay locking module starts timing. This duration parameter can be pre-stored in non-volatile memory or dynamically updated via the communication interface. During timing, the module outputs a latching signal, blocking the trigger signal of the secondary voltage regulator module, ensuring that the slave voltage regulator remains silent during the operation of the master voltage regulator, thereby achieving physical isolation of the adjustment behavior in the time dimension.

[0049] The secondary voltage regulation module, after the time delay lockout period expires, controls the slave voltage regulator to perform secondary voltage level adjustment based on the real-time node voltage deviation and the preset voltage regulation target. This module integrates a voltage sampling circuit, an analog-to-digital converter, and PID control logic. When the time delay lockout module finishes timing and releases the lockout signal, the secondary voltage regulation module is reactivated, real-time acquisition of node voltage, calculation of the deviation from the target voltage, and output control commands to drive the on-load tap changer for fine adjustment. Since the main voltage regulator is already in a steady state at this time, the secondary adjustment can accurately compensate for the remaining voltage deviation, avoiding the risk of over-regulation.

[0050] Furthermore, the main voltage regulator is configured to perform iterative adjustments to its voltage level in response to changes in power flow direction in the distribution network or disturbances in the output of distributed power sources, and to trigger the one-way communication module to issue a voltage regulation action trigger command. This configuration reflects the overall collaborative workflow of the device: the main voltage regulator senses the disturbance -> triggers the one-way communication module to send a command -> receives the command from the voltage regulator -> the voltage level reset module operates -> the delay locking module times the time -> the secondary voltage regulation module executes the command.

[0051] In a preferred embodiment of this invention, the voltage regulating device is a multi-stage series voltage regulating device consisting of no fewer than three units, including one master voltage regulating device and at least two slave voltage regulating devices. Under this architecture, the unidirectional communication module is configured to support either a one-to-many broadcast unidirectional command transmission architecture or a chain-recursive unidirectional command transmission architecture. Specifically, in a one-to-many broadcast architecture, the unidirectional communication module of the master voltage regulating device needs to be configured with a high-power or wide-coverage transmitter to ensure that the signal can simultaneously cover all downstream slave voltage regulating devices; while in a chain-recursive architecture, each slave voltage regulating device, in addition to having a receiver for receiving upstream commands, also needs its unidirectional communication module configured with a transmitter for forwarding commands downstream, thereby achieving the tiered transmission of trigger signals. This modular architecture design allows the device of this embodiment to flexibly adapt to power distribution lines of different lengths and topologies, possessing strong field deployment capabilities.

[0052] Example 5: To more intuitively verify the technical effectiveness of the method described in this invention in eliminating the risk of voltage over-regulation, this embodiment is described in detail with reference to the actual working condition of a 10kV distribution line with distributed power supply access.

[0053] The application scenario is as follows: A 10kV distribution line is 15 kilometers long, connecting to a substation at its head. Two feeder voltage regulators are connected in series at the middle and tail sections of the line. The regulator in the middle section is designated as the main regulator (registered as regulator A), and the regulator at the tail section is designated as the slave regulator (registered as regulator B). Both regulators have a rated capacity of 2000kVA, a voltage regulation range of -10% to +10%, and a total of 9 adjustable taps (-4 to +4, with 0 as the middle tap). The single-taper operation interval is set to 60 seconds. A distributed photovoltaic power source with an installed capacity of 3MW is connected at the tail section of the line.

[0054] The simulated operating condition is a "forward to reverse power flow" process. Initially, the photovoltaic output is low, and the line load is mainly supplied by the substation, with the power flow direction from the substation to the load side (forward). At this time, both voltage regulator A and voltage regulator B are operating at the +2 level to compensate for the line voltage drop and maintain the terminal voltage within the acceptable range.

[0055] If the master-slave collaborative control logic described in this invention is not adopted, i.e., the two voltage regulators adjust independently based solely on the local voltage, the adjustment process is as follows: As the solar intensity increases, the photovoltaic output rises rapidly and exceeds the local load, causing the power flow through voltage regulator B to reverse first. After detecting the reverse power flow, voltage regulator B's local control logic determines that it needs to lower its level to adapt to the voltage distribution under the reverse power flow, so it adjusts from +2 level to 0 level. At the same time, since the photovoltaic output is still increasing, the power flow through voltage regulator A also reverses subsequently. Voltage regulator A also detects the reverse power flow and begins to perform a downshift operation, adjusting from +2 level to 0 level. During this process, the downshift action of voltage regulator A will cause its downstream line voltage to rise further, while voltage regulator B is in the process of downshifting or has just completed downshifting. Since the adjustment actions of the two voltage regulators overlap in time and are in the same direction (both downshifting), their adjustment effects are superimposed on the line. Specifically, the voltage on the large side (i.e., the input side) of voltage regulator B is subjected to a double boost effect in a short period of time, which can easily exceed the voltage limit (such as exceeding 10.7kV), thereby triggering a high voltage over-limit alarm, or even causing the photovoltaic inverter to disconnect from the grid due to overvoltage protection. This is a typical over-regulation phenomenon caused by "double regulation superposition".

[0056] The adjustment process after applying the method of this invention is as follows: When the increase in photovoltaic output causes the power flow through voltage regulator A to reverse, voltage regulator A, as the main voltage regulator, responds to the change in the power flow direction of the distribution network and performs iterative adjustment of the voltage level (preparing to adjust from +2 level to 0 level). At the moment when voltage regulator A starts to act, it sends a voltage regulation action trigger command to the downstream voltage regulator B through a one-way command transmission path.

[0057] Upon receiving the instruction, voltage regulator B immediately performs two key actions: First, it forcibly resets its own gear to the preset reference gear (set to the middle gear 0 in this embodiment). This action quickly eliminates the cumulative voltage rise effect that might have been caused by voltage regulator B being in the +2 gear position, placing it in a neutral and safe initial state. Subsequently, voltage regulator B enters a time-delay lockout state. According to the parameters of this embodiment, the time-delay lockout duration is determined by the product of the single-gear operation interval of the main voltage regulator (60 seconds) and the total number of adjustable gears (9 gears), i.e., the lockout duration is 540 seconds.

[0058] Over the next 540 seconds, voltage regulator A independently completes the full-range adjustment process from +2 to 0, during which the line voltage distribution is gradually adjusted. Because voltage regulator B is in a time-delay locked state, its automatic voltage regulation logic is locked, remaining stationary and no longer responding to line voltage fluctuations. This physical time isolation mechanism ensures that the adjustment action of voltage regulator A is not interfered with by the action of voltage regulator B, and also avoids the superposition of their adjustment effects.

[0059] When the time delay lockout period expires, voltage regulator A has completed its adjustment and stabilized at level 0, and the power flow distribution of the line has tended towards a new steady state. At this time, voltage regulator B unlocks and performs a secondary level adjustment based on the real-time node voltage deviation and the preset voltage regulation target. Since the system has now eliminated the dynamic disturbances during the adjustment process, voltage regulator B only needs to make fine adjustments based on the current steady-state voltage (for example, if the voltage is slightly low, increase the level by one step; if the voltage is within acceptable limits, keep it at level 0) to accurately maintain the node voltage within the acceptable range.

[0060] As can be seen from the above positive and negative comparisons, this invention, by establishing master-slave collaborative logic, a forced reversion mechanism, and a time delay locking mechanism, successfully cuts off the "dual regulation superposition" path of multi-level voltage regulators under power flow reversal conditions, effectively avoiding the risk of high voltage exceeding the limit on the downstream voltage regulator side, and significantly improving the voltage stability of distribution networks with distributed power sources.

[0061] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.

Claims

1. A method for eliminating the risk of over-regulation in a voltage step control procedure, characterized by, include: A master-slave collaborative control logic is configured for voltage regulating equipment deployed in series in power distribution lines, so that the voltage regulating equipment is divided into master voltage regulating equipment and slave voltage regulating equipment, and a one-way command transmission path is established between the master voltage regulating equipment and the slave voltage regulating equipment. When the master voltage regulating equipment performs iterative adjustment of the tap level in response to the switching of power flow direction in the distribution network or the output disturbance of distributed power sources, it sends a voltage regulating action trigger command to the slave voltage regulating equipment through the one-way command transmission path. After receiving the voltage regulating action trigger command, the slave voltage regulating equipment forces its own tap level back to the preset reference tap level and enters a time delay lock state that matches the full tap level adjustment time of the master voltage regulating equipment. After the time delay lock period expires, the slave voltage regulating equipment performs secondary tap level adjustment based on the real-time node voltage deviation and the preset voltage regulation target.

2. The method for eliminating the risk of over-regulation in a voltage step control procedure according to claim 1, characterized in that, The voltage regulating device is a multi-stage series voltage regulating device of no less than three units, including one master voltage regulating device and at least two slave voltage regulating devices; the master voltage regulating device and each slave voltage regulating device form a one-to-many broadcast unidirectional command transmission architecture or a chain recursive unidirectional command transmission architecture.

3. A method for eliminating the risk of over-regulation in a voltage step control procedure according to claim 1 or 2, characterized in that, The duration of the time-delay lockout state is determined by the product of the single-gear operation interval of the main voltage regulator and the total number of adjustable gears.

4. The method for eliminating the risk of over-regulation in a voltage step control procedure according to claim 3, characterized in that, The duration of the time delay lock state is not less than the maximum time required for the main voltage regulating device to complete the full range gear adjustment.

5. The method for eliminating the risk of over-regulation in a voltage step control procedure according to claim 2, characterized in that, When the main voltage regulator and each slave voltage regulator form a chain-recursive unidirectional command transmission architecture, the duration of the delay lock state of the downstream slave voltage regulator is dynamically shortened based on the duration of the delay lock state already completed by the upstream slave voltage regulator; the magnitude of the dynamic shortening is adaptively determined by combining the power grid operation model with real-time power flow and voltage conditions.

6. The method for eliminating the risk of over-regulation in a voltage step control procedure according to claim 5, characterized in that, The magnitude of the dynamic reduction is determined adaptively through a power grid operation model combined with real-time power flow and voltage conditions, specifically: The power grid operation model collects the actual adjustment time of the upstream voltage regulating equipment in real time, and compares the actual adjustment time with the preset maximum delay lock time. If the absolute value of the difference between the actual adjustment time of the upstream voltage regulator and the preset maximum delay lock-in time is greater than the set adjustment threshold, then based on the actual adjustment time and combined with the downstream voltage regulator's own adjustment parameters, current voltage deviation and power flow conditions, the initial delay lock-in time of the downstream voltage regulator is dynamically shortened and corrected to determine the optimal delay lock-in time that is suitable for the current operating conditions.

7. The method for eliminating the risk of over-regulation in a voltage step control procedure according to claim 1, characterized in that, The voltage regulating equipment specifically comprises at least two feeder voltage regulating devices, with the main voltage regulating device and the slave voltage regulating device arranged sequentially along the power transmission direction of the feeder.

8. The method for eliminating the risk of over-regulation in a voltage staging control process of claim 1, wherein, The one-way command transmission path adopts a wired carrier or wireless private network communication mode, and the frame structure sent by the one-way command transmission path only contains voltage regulation action trigger identifier and device identification code information.

9. An apparatus for eliminating over-regulation risk in a voltage grading control process, applicable to the method for eliminating over-regulation risk in a voltage grading control process as described in any one of claims 1-8, characterized in that, include: Master-slave configuration module, one-way communication module, gear reset module, delay lock module, and secondary voltage regulation module; The master-slave configuration module is used to configure master-slave collaborative control logic for voltage regulating devices deployed in series in power distribution lines, and to divide the voltage regulating devices into master voltage regulating devices and slave voltage regulating devices. The one-way communication module is used to establish a one-way command transmission path between the main voltage regulator and the slave voltage regulator to transmit voltage regulation action trigger commands. The gear reset module is used to forcibly reset its own gear to a preset reference gear after receiving a pressure regulation action trigger command from the pressure regulating device. The time delay locking module is used to control the voltage regulating device to enter a time delay locking state that matches the full range adjustment time of the main voltage regulating device; The secondary voltage regulation module is used to control the voltage regulation device to perform secondary gear adjustment based on the real-time node voltage deviation and the preset voltage regulation target after the time delay lock period expires. The main voltage regulating device is configured to perform iterative adjustment of the voltage level in response to the switching of power flow direction in the distribution network or the disturbance of the output of distributed power sources, and to trigger the one-way communication module to send a voltage regulation action trigger command.

10. The apparatus for eliminating the risk of over-regulation in a voltage staging control procedure according to claim 9, characterized in that, The voltage regulating device is a multi-stage series voltage regulating device of no less than three units, including one main voltage regulating device and at least two slave voltage regulating devices; The one-way communication module is configured to support a one-to-many broadcast one-way command transmission architecture or a chain-recursive one-way command transmission architecture.

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