Voltage and frequency coordinated multiplexing control method for distribution network under high proportion of new energy

Abstract

This invention discloses a control method for coordinated reuse of voltage and frequency regulation in distribution networks under high-proportion renewable energy conditions. It relates to the fields of distribution network operation optimization and power quality control, and includes steps S1 (preprocessing and resource modeling), S2 (layered architecture construction), S3 (local adaptive coupling control), S4 (regional coordinated optimization control), and S5 (global rolling correction control). This control method breaks down the resource barriers of traditional discrete control by integrating and coordinating the reuse of voltage and frequency regulation resources in the distribution network. It maximizes the utilization of redundant capacity in power electronic equipment, significantly improves equipment utilization, reduces redundant equipment configuration in the power grid, and lowers investment and maintenance costs. By setting multi-condition adaptive control logic and clear resource priority rules, it completely solves the frequency and voltage regulation conflict problem under high-proportion renewable energy scenarios, simultaneously improving the voltage and frequency stability of the distribution network and significantly improving power quality.

Description

Technical Field

[0001] This invention relates to the field of power distribution network operation optimization and power quality control technology, specifically a method for coordinated multiplexing control of voltage and frequency regulation in power distribution networks under a high proportion of renewable energy sources. Background Technology

[0002] With the large-scale integration of new energy sources such as distributed photovoltaic and decentralized wind power into medium and low voltage distribution networks, the distribution network exhibits characteristics of high-proportion new energy penetration, power electronics, and strong uncertainty of source and load. New energy power generation equipment is connected to the grid through power electronic converters, which has the characteristics of low inertia, decoupling and controllable active and reactive power, and random fluctuation of output. This is significantly different from the control characteristics of traditional thermal power and hydropower synchronous units.

[0003] For example, patent CN112838614A discloses a frequency regulation-voltage regulation coordinated control method and system for photovoltaic power plants. The method includes: constructing a frequency regulation-voltage regulation coordinated control optimization model with the objective function of maximizing the sum of reactive power regulation capacity of photovoltaic units within the photovoltaic power plant, and with the active power frequency regulation command from the upper-level power grid and the voltage of each node within the plant as constraints; using the active power at the grid connection point of the photovoltaic power plant, the active power of the photovoltaic units, and the voltage amplitude of each node within the plant at the current moment as inputs to the frequency regulation-voltage regulation coordinated control optimization model, and outputting the output power of the photovoltaic units at the next moment, thereby controlling the operation of the photovoltaic power plant. Under the premise that there is adjustable space for the photovoltaic power plant's load reduction operation, the output power of each photovoltaic unit within the photovoltaic power plant tracks the frequency regulation command from the upper-level power grid in real time, while simultaneously satisfying the voltage constraints at the grid connection point and each node within the plant, thus achieving the purpose of frequency regulation-voltage regulation coordinated control.

[0004] For example, patent CN111416367B discloses a collaborative control method for multi-scenario applications of energy storage, including the following steps: determining the time period of the peak-shaving demand scenario and the active power output required for peak-shaving; identifying the demand scenario in the current frequency regulation and voltage regulation scenarios of energy storage; determining the scenario mode corresponding to energy storage under the frequency regulation and voltage regulation demand scenarios; calculating the active power output of energy storage required for frequency regulation and the reactive power output of energy storage required for voltage regulation through the control method of energy storage participating in a single frequency regulation scenario and energy storage participating in a single voltage regulation scenario, wherein the algebraic sum of the active power output required for peak-shaving and the active power output of energy storage required for frequency regulation is the expected active power value of energy storage, and the reactive power output of energy storage required for voltage regulation is the expected reactive power value of energy storage. This invention aims to fully utilize the remaining capacity of energy storage to improve the frequency and voltage environment of the power grid under the background of existing energy storage power stations meeting the peak shaving and valley filling scenarios of the power grid, thereby alleviating the pressure of frequency regulation and voltage regulation of the unit and extending the life of the unit.

[0005] Currently, power distribution networks generally adopt a separate independent control mode for voltage regulation and frequency regulation, meaning that reactive power resources are dedicated to voltage regulation and active power resources are dedicated to frequency regulation. This control mode exposes many technical defects in scenarios with a high proportion of renewable energy integration: First, the regulation resources are severely fragmented, and the redundant apparent power of power electronic equipment such as photovoltaic inverters, energy storage converters, and V2G charging piles cannot be fully utilized, resulting in an overall equipment utilization rate of less than 50% and a large amount of regulation resources being idle; Second, there are conflicts between voltage and frequency regulation, and energy storage and inverters in the same distribution area are prone to simultaneously receiving reverse commands for voltage and frequency regulation. The problems include: 1) Power exceeding limits and control failure, leading to synchronous overruns of node voltage and system frequency; 2) Multi-timescale control mismatch, with no hierarchical coordination mechanism between slow voltage regulation equipment such as OLTC and capacitor banks and fast regulation equipment such as energy storage and inverters, resulting in frequent switching and operation of equipment and severe losses; 3) Limited renewable energy consumption, with frequency and voltage disturbances caused by fluctuations in renewable energy output not being effectively mitigated, which is an important reason for curtailment of solar and wind power; 4) Poor economic efficiency of power grid construction, requiring repeated configuration of dedicated energy storage and reactive power compensation equipment for voltage and frequency regulation, significantly increasing power grid investment and operation and maintenance costs.

[0006] Some existing technologies attempt to implement frequency-voltage coordinated regulation, but they generally suffer from problems such as simple resource reuse logic, poor adaptability to operating conditions, lack of clear priority constraints, and weak coordination among multiple devices. They cannot solve the problems of regulation conflicts and resource waste in high-fluctuation new energy scenarios, and are difficult to meet the needs of safe, efficient, and economical operation of high-proportion new energy distribution networks.

[0007] To address the aforementioned issues, there is an urgent need for innovative designs based on existing methods. Summary of the Invention

[0008] The purpose of this invention is to provide a voltage and frequency regulation coordinated reuse control method for distribution networks under high-proportion renewable energy, in order to solve the problems in the prior art mentioned above, where some solutions attempt to carry out frequency and voltage coordinated regulation, but generally suffer from simple resource reuse logic, poor adaptability to operating conditions, lack of clear priority constraints, and weak coordination among multiple devices. These problems cannot solve the regulation conflict and resource waste issues under high-fluctuation renewable energy scenarios, and are difficult to meet the needs of safe, efficient, and economical operation of high-proportion renewable energy distribution networks.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a method for coordinated multiplexing control of voltage and frequency regulation in distribution networks under high-proportion renewable energy sources, comprising the following steps:

[0010] Step S1: Preprocessing and resource modeling, collect all controllable resource parameters in the distribution network, establish the apparent power capacity constraint model of each power electronic device, and divide the daily arbitrage fixed power area, frequency regulation reserve active power area, and voltage and frequency regulation shared redundant power area.

[0011] Step S2: Layered architecture construction, building a three-layer frequency and voltage collaborative multiplexing control architecture with bottom-layer local autonomy, middle-layer regional collaboration, and top-layer global coordination, distinguishing between second-level fast power electronic regulation resources and minute-level slow traditional voltage regulation resources, and setting multi-resource and multi-operating condition regulation priority rules;

[0012] Step S3: Local adaptive coupling control. The bottom edge terminal collects real-time data on voltage and frequency of each node. Based on the frequency-voltage coupling droop control algorithm, it dynamically allocates active frequency regulation power and reactive voltage regulation power within the equipment capacity constraint to realize local reuse of frequency and voltage resources of a single device.

[0013] Step S4: Regional collaborative optimization and control. The mid-level feeder controller takes a single feeder / distribution station area as the control unit. Based on voltage sensitivity and frequency power deficit sensitivity, it continuously optimizes the P / Q power ratio of multiple devices in the jurisdiction to realize mutual assistance and reuse of control resources in the region and synchronously link flexible loads to participate in auxiliary control.

[0014] Step S5: Global rolling correction and control. Based on the day-ahead renewable energy output and load forecast data, the top-level distribution network master station pre-allocates the entire network's voltage regulation and frequency regulation reserve capacity pools. Combined with the real-time grid operation status, the proportion of the dual capacity pools is dynamically adjusted. Through the bottom-line control of traditional voltage regulation equipment, the entire process of voltage and frequency regulation of the distribution network is coordinated and reused.

[0015] Preferably, the controllable resources in step S1 include distributed new energy grid-connected inverters, energy storage converters (PCS), V2G charging piles, flexible and controllable loads, and traditional discrete voltage regulation equipment.

[0016] Preferably, the specific steps of step S1 are as follows:

[0017] Step S11: Collect all controllable resource parameters, traverse all control units of the target distribution substation and feeder, collect static parameters in three categories, and simultaneously collect the bus voltage, system frequency and current output of each node in real time;

[0018] Step S12: Standardize and preprocess multi-source monitoring data to eliminate interference from bad data and avoid distortion in subsequent optimization and droop control calculations;

[0019] Step S13: Model mathematical constraints for different types of equipment;

[0020] Step S14: Single device power three-zone quantization modeling, the rated apparent capacity of energy storage and distributed power sources is divided into three independent power zones, and the quantization boundary is assigned.

[0021] Preferably, the three independent power ranges in step S14 are: a fixed power range. FM dedicated active power zone Shared redundancy area with voltage regulation and frequency regulation .

[0022] Preferably, the control priority rule in step S2 is as follows: the equipment safety operation constraint has the highest priority, followed by the node voltage qualification constraint, then the distribution network frequency qualification constraint, and finally the control economy is optimal; power electronic second-level fast resources prioritize response to frequency and voltage disturbances, while traditional OLTC and capacitor bank minute-level slow resources only take the fallback action when fast resources are exhausted and frequency and voltage continuously exceed limits.

[0023] Preferably, the coupling equation of the frequency-voltage coupled droop control algorithm in step S3 is: , ,in, , These represent the initial active and reactive power outputs of the equipment. This is the frequency droop coefficient. This is the voltage droop factor. , These are the system's real-time frequency and rated frequency, respectively. , These are the node's real-time voltage and rated voltage, respectively.

[0024] Preferably, the local adaptive control logic in step S3 is as follows: when the voltage exceeds the limit but the frequency is normal, all redundant capacity of the equipment prioritizes reactive power output to participate in voltage regulation, while the active power output remains unchanged at its initial value; when the frequency exceeds the limit but the voltage is normal, the redundant active capacity of the equipment participates in frequency regulation, while the reactive power output remains unchanged at its current value; when both frequency and voltage exceed the limit, the redundant capacity of the equipment is dynamically split according to a preset weight, and active power frequency regulation and reactive power voltage regulation are allocated synchronously to ensure that the node voltage is qualified; when the equipment capacity is exhausted and the frequency and voltage exceedance cannot be eliminated, the control deficit is reported to the upper-level area controller.

[0025] Preferably, the regional collaborative optimization and control in step S4 specifically involves: for short-term power fluctuations of new energy sources at the second level, adjusting the P / Q allocation ratio of each device within the jurisdiction, and adopting a zoned control strategy that prioritizes frequency regulation for near-end energy storage and voltage regulation for far-end inverters; for continuous wind and solar power output disturbances, initiating flexible and controllable load demand response, and simultaneously reducing line voltage drop to achieve auxiliary voltage regulation by reducing active load, shifting auxiliary secondary frequency regulation, and shifting auxiliary secondary frequency regulation.

[0026] Preferably, the global rolling correction regulation in step S5 specifically involves: based on a 15-minute model predictive control algorithm, inputting real-time forecast data of new energy output and load, and taking the minimum node voltage deviation, minimum frequency fluctuation, and minimum overall regulation cost as optimization objectives, continuously optimizing the voltage regulation and frequency regulation capacity ratio of the entire network, predicting power fluctuations in advance and pre-allocating regulation resources, and avoiding resource contention and regulation conflicts among multiple devices.

[0027] Preferably, the specific steps of step S5 are as follows:

[0028] Step S51: Aggregation of network-wide predictive data and assessment of operating conditions;

[0029] Step S52: Dynamic pre-division of the entire network voltage and frequency regulation dual capacity pool;

[0030] Step S53: Multi-objective model prediction and rolling optimization solution;

[0031] Step S54: Cross-regional resource sharing and overall coordination;

[0032] Step S55: Traditional slow-speed equipment as a backup and coordinated control;

[0033] Step S56: Coordinated correction of energy storage lifetime and economic constraints;

[0034] Step S57: Periodic rolling updates and closed-loop archiving across the entire network.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] 1. By integrating and reusing voltage and frequency regulation resources in the distribution network, the resource barriers of traditional discrete control are broken down, the redundant capacity of power electronic equipment is maximized, the equipment utilization rate is greatly improved, the configuration of redundant equipment in the power grid is reduced, and the investment and operation and maintenance costs are reduced.

[0037] 2. By setting up multi-condition adaptive control logic and clear resource priority rules, the frequency and voltage control conflict problem in high-proportion renewable energy scenarios is completely resolved, and the voltage and frequency stability of the distribution network is improved simultaneously, significantly improving power quality.

[0038] 3. Construct a multi-time-scale hierarchical control system, combining predictive model prediction optimization with local rapid autonomous control, adapting to the random fluctuation characteristics of new energy, significantly improving the anti-disturbance capability of the distribution network, and effectively improving the level of new energy consumption;

[0039] 4. Balancing regulation performance and equipment lifespan, by limiting the frequent operation of traditional equipment and optimizing energy storage charging and discharging strategies, it reduces equipment losses, extends equipment lifespan, and has strong economic efficiency and engineering practicality. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the overall method flow of the present invention.

[0041] Figure 2 This is a schematic diagram of step 1 of the present invention;

[0042] Figure 3 This is a schematic diagram of step 5 of the present invention. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0044] This application provides a method for voltage and frequency regulation coordinated multiplexing control of distribution networks under high-proportion renewable energy. To better understand the above technical solution, it will be described in detail below with reference to the accompanying drawings and specific implementation methods. Figures 1-3 As shown in this embodiment of the present application, the method for coordinated multiplexing control of voltage and frequency regulation in distribution networks under high proportion of renewable energy includes the following steps:

[0045] Step S1: Preprocessing and resource modeling, collect all controllable resource parameters in the distribution network, establish the apparent power capacity constraint model of each power electronic device, and divide the daily arbitrage fixed power area, frequency regulation reserve active power area, and voltage and frequency regulation shared redundant power area.

[0046] It should be noted that, in this application, controllable resources include distributed renewable energy grid-connected inverters, energy storage converters (PCS), V2G charging piles, flexible and controllable loads, and traditional discrete voltage regulation equipment, and the specific steps are as follows:

[0047] Step S11: Collect all controllable resource parameters, traverse all control units of the target distribution substation and feeder, collect static parameters in three categories, and simultaneously collect the bus voltage, system frequency and current output of each node in real time;

[0048] Step S12: Standardize and preprocess multi-source monitoring data to eliminate interference from bad data and avoid distortion in subsequent optimization and droop control calculations;

[0049] Step S13: Model mathematical constraints for different types of equipment;

[0050] Step S14: Single device power three-zone quantization and modeling, the rated apparent capacity of energy storage and distributed power sources is divided into three independent power zones, and the quantization and boundary assignment are performed.

[0051] In practice, three types of static parameters are first collected. These include power electronic resources (photovoltaic inverters, energy storage PCS, V2G charging piles), flexible and controllable loads, and traditional voltage regulation equipment. For power electronic resources, the rated apparent power is collected. The data collection includes: rated active / reactive power limits, converter response delay, allowable active power downsizing margin, maximum charging and discharging power of BMS energy storage, and converter reactive power regulation range; for flexible and controllable loads: collect the load capacity that can be switched, load shifting time, and demand response delay; for traditional voltage regulating equipment (OLTC, parallel capacitors / reactors): collect the tap adjustment range, single-group switching capacity, and shortest operating interval; it also requires synchronous real-time collection of bus voltage at each node, system frequency, and current equipment output; then, multi-source monitoring data standardization preprocessing is performed to eliminate bad data interference and avoid distortion in subsequent optimization and droop control calculations; abnormal data is removed, including out-of-range, sudden spikes, and distorted data due to communication interruptions; finally, dimensional normalization is performed, i.e., unifying active power. No merit ,Voltage ,frequency Units of measurement; then align the data time series, calibrating and aligning the timestamps of heterogeneous data from multiple terminals according to a unified sampling period (5s / 15min) to form a standardized resource database; perform mathematical constraint modeling for different types of equipment, including establishing a single-machine general mathematical model based on the power physical constraints of the converter, which needs to satisfy: Where P is the real-time active power of the equipment, and Q is the real-time reactive power of the equipment. The rated apparent power of the equipment; for new energy inverters, establish an active power derating margin model and set a reserved fixed active power margin. For frequency regulation; for energy storage PCS: establish upper and lower limits of charging and discharging power and SOC lifespan constraint models; for traditional voltage regulation equipment: establish switch frequency and switch interval constraint models, restricting participation in short-term frequency regulation, and classifying resources by response speed: second-level fast reuse resources, medium-duration flexible load resources, and minute-level fallback voltage regulation resources; single-device power three-zone quantitative partitioning model, dividing the rated apparent capacity of energy storage and distributed power sources into three independent power zones, quantifying and assigning boundaries, wherein the three independent power zones are: fixed power zone FM dedicated active power zone Shared redundancy area with voltage regulation and frequency regulation Fixed power region Fixed for self-consumption, peak-valley arbitrage, and base load power supply; capacity locked; does not participate in voltage or frequency regulation; dedicated active power zone for frequency regulation. : Reserves a fixed active power margin in advance, with dedicated primary / secondary frequency regulation for the system, and does not occupy reactive power capacity under normal circumstances; voltage and frequency regulation share the redundancy area. The remaining surplus apparent capacity after deducting the first two zones is dynamically reused capacity; when only the frequency exceeds the limit and the voltage is within the limit, the shared capacity is converted into active power and participates in frequency regulation; when only the voltage exceeds the limit and the frequency is within the limit, the shared capacity is converted into reactive power and participates in local voltage regulation; when both frequency and voltage exceed the limit, active power / reactive power is split according to the preset weight, and frequency and voltage regulation are taken into account simultaneously.

[0052] In this embodiment, through preprocessing and resource modeling, the physical boundaries of power reuse can be defined, avoiding regulation conflicts at the source. Through parameter sorting and label modeling, it distinguishes between second-level power electronic resources, medium- and long-term flexible loads, and minute-level mechanical voltage regulating equipment, naturally supporting a three-layer collaborative control architecture. This ensures that fast resources are prioritized to smooth out short-term disturbances, while slow equipment is only used as a backup, reducing frequent switching of OLTC and capacitors. Moreover, the original data is processed by removing bad values, unifying units, and aligning time sequences, eliminating inconsistencies in heterogeneous data from multiple manufacturers' terminals, inverters, and energy storage BMS. This avoids erroneous adjustments in local vertical control, regional optimization, and MPC global optimization due to abnormal data. The fixed area, frequency regulation dedicated area, and shared redundancy area are quantitatively divided, clarifying when idle capacity is returned to frequency regulation and when it is switched to voltage regulation. This provides a quantitative calculation basis, eliminating the reliance on experience for rough power allocation, which is a prerequisite for the engineering implementation of collaborative reuse control.

[0053] Step S2: Layered architecture construction, building a three-layer frequency and voltage collaborative multiplexing control architecture with bottom-layer local autonomy, middle-layer regional collaboration, and top-layer global coordination, distinguishing between second-level fast power electronic regulation resources and minute-level slow traditional voltage regulation resources, and setting multi-resource and multi-operating condition regulation priority rules;

[0054] It should be noted that in this application, the control priority rule is as follows: the equipment safety operation constraint has the highest priority, followed by the node voltage qualification constraint, then the distribution network frequency qualification constraint, and finally the control economy is optimal; power electronic second-level fast resources prioritize response to frequency and voltage disturbances, while traditional OLTC and capacitor bank minute-level slow resources only take the fallback action when fast resources are exhausted and frequency and voltage continuously exceed limits.

[0055] In practical implementation, the control scope, response latency, and core functions of each layer of the three-layer architecture are first clearly defined to achieve decoupling of responsibilities and clear division of duties: The bottom layer deploys edge terminals, corresponding to millisecond to second-level responses, responsible for real-time local frequency and voltage correction of single nodes and single devices, and achieving rapid suppression of instantaneous disturbances by relying on frequency and voltage coupling droop control; the middle layer deploys feeder / distributor area controllers, corresponding to second to minute-level responses, with a single feeder or single distribution area as the smallest control unit, responsible for resource sharing among multiple devices within the area, P / Q power ratio optimization, and flexible load demand response linkage; the top layer deploys the distribution network master station dispatching platform, corresponding to minute to hour-level responses, responsible for forecasting the output and load of new energy sources across the entire network, and voltage and voltage regulation. Frequency capacity pool pre-allocation, multi-regional resource coordination and balancing, and global optimization of steady-state operating conditions; then, based on the response speed and action characteristics of various control resources, precise binding and layering of resources and levels are achieved: photovoltaic inverters, energy storage PCS, V2G charging piles, and other second-level power electronic fast resources are all connected to the bottom-level edge terminal for rapid smoothing of instantaneous frequency and voltage fluctuations; interruptible loads, shiftable loads, and other medium-duration flexible control resources are connected to the middle-level regional controller for continuous disturbance auxiliary control; minute-level mechanical slow fallback resources such as OLTC on-load tap changers, parallel capacitors, and reactors are connected to the top-level master station for management, used only for steady-state deviation correction after rapid resource depletion, preventing... Slow-speed equipment operates frequently; standardized control priority logic is uniformly written into the three-layer architecture to form a consistent control judgment basis across the entire domain: the priority from high to low is equipment safety operation constraints, node voltage qualification constraints, distribution network frequency qualification constraints, and optimal control operation economy; resource action timing rules are simultaneously solidified, with second-level power electronic resources prioritizing responses to all short-term frequency and voltage disturbances, and slow traditional voltage regulating equipment is prohibited from participating in instantaneous frequency and voltage regulation, only performing fallback control after frequency and voltage continuously exceed limits and rapid control resources are exhausted, thus avoiding control conflicts and equipment losses from a mechanism perspective; a closed-loop mechanism of three-layer architecture linkage and hierarchical support is established: when the control capacity of the bottom-level equipment is exhausted and node frequency cannot be eliminated... When the voltage exceeds the limit, the system automatically reports the control deficit to the upper-level regional controller. If the mid-level regional resources are still unable to suppress the disturbance across the entire region, the system requests network-wide resource support from the upper-level distribution network master station. The top-level master station coordinates cross-regional backup capacity and traditional backup equipment to complete the final steady-state correction, forming a complete collaborative control closed loop of "local self-governance - regional mutual assistance - global backup". For four types of operating conditions of new energy single voltage limit exceedance, single frequency limit exceedance, frequency and voltage synchronization limit exceedance, and steady-state normal operation, the corresponding operating modes are solidified within the hierarchical architecture to realize the adaptive switching of hierarchical collaborative logic under different disturbance scenarios, ensuring that the reuse of active power frequency regulation and reactive power voltage regulation resources are orderly and reasonably allocated under various operating conditions, avoiding disorderly control and resource waste.

[0056] In this embodiment, a three-layer architecture is used to bind control resources in a time-series manner. Second-level fast power electronic resources, medium-duration flexible load resources, and minute-level traditional mechanical backup resources are categorized and adapted to corresponding control levels. Short-term, instantaneous new energy power fluctuations are smoothed out by the bottom-level fast resources at the millisecond level, while continuous steady-state deviations are optimized and corrected by the middle and top-level resources. This completely solves the defects of traditional single-layer control, such as the mixing of fast and slow devices, frequent switching of mechanical equipment, and control lag or over-adjustment. It significantly reduces the mechanical losses of OLTCs and capacitor banks, extending equipment lifespan. The three-layer architecture achieves hierarchical decoupling of control authority. The bottom layer is responsible for local correction of single nodes, the middle layer for regional resource sharing, and the top layer for overall network optimization. Each layer performs its own function and operates in a closed loop, eliminating the problems of disordered response of multiple devices, overlapping and conflicting voltage and frequency regulation commands, and resource contention for redundant capacity under traditional centralized single-level control. This ensures that the dynamic reuse process of active power frequency regulation and reactive power voltage regulation is orderly, controllable, and stable.

[0057] Step S3: Local adaptive coupling control. The bottom edge terminal collects real-time data on voltage and frequency of each node. Based on the frequency-voltage coupling droop control algorithm, it dynamically allocates active frequency regulation power and reactive voltage regulation power within the equipment capacity constraint to realize local reuse of frequency and voltage resources of a single device.

[0058] It should be noted that, in this application, the coupling equation of the frequency-voltage coupled droop control algorithm is: , ,in, , These represent the initial active and reactive power outputs of the equipment. This is the frequency droop coefficient. This is the voltage droop factor. , These are the system's real-time frequency and rated frequency, respectively. , These are the real-time voltage and rated voltage of the nodes, respectively. The local adaptive control logic is as follows: when the voltage exceeds the limit but the frequency is normal, all redundant capacity of the equipment prioritizes reactive power output to participate in voltage regulation, while the active power output remains unchanged at its initial value; when the frequency exceeds the limit but the voltage is normal, the redundant active capacity of the equipment participates in frequency regulation, while the reactive power output remains unchanged at its current value; when both frequency and voltage exceed the limit, the redundant capacity of the equipment is dynamically split according to preset weights, and active power frequency regulation and reactive power voltage regulation are allocated synchronously to prioritize ensuring that the node voltage is qualified; when the equipment capacity is exhausted and the frequency and voltage exceedance cannot be eliminated, the control deficit is reported to the upper-level area controller.

[0059] In practice, the real-time voltage of the nodes is collected in real time at a millisecond-level sampling frequency through the edge control terminals of each distributed device. System real-time frequency Current active power output of the equipment Unproductive efforts Combined with the rated voltage of the power grid Rated frequency Real-time calculation of voltage deviation Frequency deviation Based on the distribution network frequency and voltage qualification thresholds, the system automatically determines the current power grid operating condition and distinguishes four operating scenarios: single voltage limit exceedance, single frequency limit exceedance, synchronous frequency and voltage limit exceedance, and frequency and voltage bistable normal operating condition; based on the rated apparent power of the equipment obtained through preprocessing and resource modeling... Based on the current operating conditions and relying on the apparent power hard constraint The system calculates the remaining reusable redundant apparent capacity of the equipment in real time, and, combined with preset power zoning rules, locks down the surplus active capacity available for active frequency regulation and the surplus reactive capacity available for reactive voltage regulation, thus defining the upper limit of power for this regulation and preventing overcapacity operation. It also invokes the built-in frequency-voltage coupling droop control equation to dynamically calculate the optimal output power of the equipment based on the real-time frequency-voltage deviation. , Based on the preliminary operating condition assessment results, the corresponding power reuse control logic is adaptively matched, strictly adhering to the preset control priority; the calculated control logic is then applied. , The output power undergoes a secondary verification, being substituted into the apparent power constraint formula again for verification to ensure that the total apparent power after regulation does not exceed the equipment's rated capacity. If a power limit violation risk occurs, the frequency and voltage regulation output power is automatically reduced proportionally, prioritizing the retention of high-priority voltage regulation power to ensure safe and stable equipment operation and avoid overload, lockout, and tripping issues. The edge terminal will then apply the corrected optimal... , Output commands are sent to the corresponding inverters, energy storage PCS, and V2G devices to complete millisecond-level local control. After control is completed, the frequency and voltage status of the nodes is monitored in real time. If the redundant capacity of the equipment is completely exhausted and the frequency and voltage exceedance cannot be eliminated, control deficit information is automatically generated and reported to the upper-level and middle-level regional controllers in real time to request regional resource mutual assistance support and complete the bottom-level control closed loop.

[0060] In this embodiment, the control method is based on local data collection, local computation, and local execution at the edge terminal, without relying on remote dispatch commands from the upper-level master station. It can respond to frequency and voltage disturbances caused by random fluctuations in new energy sources and sudden load changes in milliseconds to seconds. It can suppress small-amplitude, high-frequency instantaneous disturbances in advance and prevent massive minor fluctuations from being transmitted to the upper-level power grid. It effectively solves the problems of delayed response and accumulation and diffusion of disturbances in traditional centralized control, and significantly improves the dynamic stability of the distribution network. It adopts frequency and voltage coupling linkage control logic, which incorporates active power frequency regulation and reactive power voltage regulation into the same capacity constraint system. According to the real-time operating conditions of the power grid, it dynamically allocates power output and can simultaneously take into account voltage quality and frequency stability. It solves the shortcomings of difficult coordinated management of frequency and voltage coupling disturbances in high-proportion new energy distribution networks from the control logic level.

[0061] Step S4: Regional collaborative optimization and control. The mid-level feeder controller takes a single feeder / distribution station area as the control unit. Based on voltage sensitivity and frequency power deficit sensitivity, it continuously optimizes the P / Q power ratio of multiple devices in the jurisdiction to realize mutual assistance and reuse of control resources in the region and synchronously link flexible loads to participate in auxiliary control.

[0062] It should be noted that, in this application, the regional coordinated optimization and control specifically refers to: for short-term power fluctuations of new energy sources at the second level, adjusting the P / Q allocation ratio of each device in the jurisdiction, and adopting a zoned control strategy of prioritizing frequency regulation of near-end energy storage and prioritizing voltage regulation of far-end inverters; for continuous wind and solar power output disturbances, initiating flexible and controllable load demand response, and simultaneously reducing line voltage drop to achieve auxiliary voltage regulation by reducing active load, shifting auxiliary secondary frequency regulation, and simultaneously reducing line voltage drop.

[0063] In practice, the regional distribution area controller collects real-time operational data from all nodes within its jurisdiction, including voltage, frequency, active / reactive power output, remaining reusable capacity, and energy storage SOC status. This data is aggregated to form a regional global resource information database. Simultaneously, it identifies regional disturbance types, distinguishing between four types of regional operating conditions: short-term high-frequency renewable energy fluctuations, persistent power deviations, overall voltage offsets, and network-wide frequency deficits. This provides data support for optimized allocation of regional resources. Based on the distribution network feeder topology, it calculates in real-time the frequency sensitivity of each device's active power output to regional frequency deviations, and the frequency sensitivity of each device to these deviations. The voltage sensitivity of reactive power output to node voltage is analyzed. Based on differences in electrical distance, the differences in frequency regulation contribution of near-end equipment and voltage regulation contribution of far-end equipment are quantified, providing a quantitative basis for the "near-end frequency regulation, far-end voltage regulation" zoned reuse strategy. The remaining active power frequency regulation capacity and remaining reactive power voltage regulation capacity of all photovoltaic inverters, energy storage PCS, and V2G charging piles in the distribution area are summarized, and the total adjustable frequency reserve capacity and total adjustable voltage reserve capacity of the area are calculated. At the same time, the adjustable potential of flexible loads that can be reduced or shifted is calculated, forming three types of reserves for regional voltage regulation, frequency regulation, and demand response. The resource pool enables comprehensive control over regional resources. A differentiated collaborative reuse strategy is implemented based on sensitivity differences: near-end energy storage and inverters with shorter electrical distances and faster response times are prioritized for active power frequency regulation tasks, quickly compensating for regional power deficits and suppressing frequency fluctuations; remote photovoltaic clusters at the line ends and sensitive to voltage fluctuations are prioritized for reactive power voltage regulation tasks, locally suppressing voltage exceedances at the end. Cross-node power sharing balances the shortcomings of insufficient single-node capacity, avoiding local resource depletion and overall resource idleness. For long-term frequency-voltage deviations caused by continuous high-volume generation, continuous declines, and significant load fluctuations in new energy sources, regional flexible load collaborative regulation is initiated. This involves reducing the active power of interruptible industrial loads and shifting temperature-controlled loads to help balance regional active power supply and demand and alleviate frequency offset. Lowering the overall load level reduces line impedance voltage drop, indirectly assisting in overall voltage balance and achieving bidirectional source-load collaborative regulation. After optimization, the apparent power constraints, allowable voltage deviation range, frequency fluctuation range, energy storage charging and discharging power limits, and SOC constraints of each device are uniformly verified to ensure that all optimization instructions do not exceed equipment operating limits. Multi-device commands are smoothed to avoid secondary disturbances caused by sudden power increases and decreases, ensuring stable, continuous, and reliable regional control. After completing this round of regional coordinated control, the improvement effect of regional frequency and voltage deviation is evaluated. If all reusable resources and flexible load resources in the region have been exhausted, and there are still persistent voltage or frequency exceedances, it is determined that the current control capacity of the distribution area is insufficient. Regional control deficit data is generated, and a support request is sent to the upper-level global master station dispatch system, entering the whole network bottom-line optimization stage, forming a mid-level control closed loop.

[0064] In this embodiment, traditional local control relies solely on the redundant capacity of single-node equipment, which can easily lead to imbalances such as local resource depletion and large-scale idle resources in neighboring nodes. This regional collaborative control pool, by aggregating distributed power sources, energy storage, V2G, and flexible load resources across the region, constructs a unified regional reserve capacity pool. This enables cross-node and cross-equipment power mutual assistance, effectively compensating for the insufficient control capacity of single nodes and significantly improving the overall voltage and frequency regulation reserve margin and disturbance resistance capability of the area. By calculating frequency and voltage sensitivity in real time, the control contribution differences between near-end and far-end equipment are distinguished, and the adaptation strategy of "near-end priority frequency regulation and far-end priority voltage regulation" is solidified. Equipment with strong frequency regulation response and short electrical distance undertakes frequency support tasks, while voltage-sensitive end photovoltaic clusters are stabilized locally. This avoids the problems of inefficient control and resource waste caused by blindly distributing power evenly, and achieves the maximum and precise reuse of limited redundant resources.

[0065] Step S5: Global rolling correction and control. Based on the day-ahead renewable energy output and load forecast data, the top-level distribution network master station pre-allocates the entire network's voltage regulation and frequency regulation reserve capacity pools. Combined with the real-time grid operation status, the proportion of the dual capacity pools is dynamically adjusted. Through the bottom-line control of traditional voltage regulation equipment, the entire process of voltage and frequency regulation of the distribution network is coordinated and reused.

[0066] It should be noted that, in this application, the global rolling correction regulation specifically refers to: based on a 15-minute model predictive control algorithm, inputting real-time forecast data of renewable energy output and load, and taking the minimum node voltage deviation, minimum frequency fluctuation, and minimum overall regulation cost as optimization objectives, continuously optimizing the voltage and frequency regulation capacity ratio of the entire network, predicting power fluctuations in advance and pre-allocating regulation resources, avoiding resource contention and regulation conflicts among multiple devices, and the specific steps are as follows:

[0067] Step S51: Aggregation of network-wide predictive data and assessment of operating conditions;

[0068] Step S52: Dynamic pre-division of the entire network voltage and frequency regulation dual capacity pool;

[0069] Step S53: Multi-objective model prediction and rolling optimization solution;

[0070] Step S54: Cross-regional resource sharing and overall coordination;

[0071] Step S55: Traditional slow-speed equipment as a backup and coordinated control;

[0072] Step S56: Coordinated correction of energy storage lifetime and economic constraints;

[0073] Step S57: Periodic rolling updates and closed-loop archiving across the entire network;

[0074] In practice, the distribution network master station first uniformly accesses the distributed photovoltaic and wind power output forecast data and regional load forecast data of the entire network. With a rolling optimization cycle of 15 minutes, it updates the future short-term renewable energy output trend and load change trend. Combined with the real-time operating status, remaining resource capacity, and frequency and voltage deviation data reported by each distribution area, it predicts typical operating conditions that the entire network will experience, such as a surge in renewable energy generation, output drop, and sudden changes in load peak and valley. It also identifies potential voltage exceedance and frequency deviation risks in advance, providing a data foundation for the pre-allocation of control resources. Based on the reusable resource capacity reported by each region, the master station summarizes and statistically analyzes the total frequency regulation reserve active power capacity and total voltage regulation reserve reactive power capacity of the entire network. Combined with the current grid security constraints and operational needs, it completes the unified zonal allocation of control resources for the entire network. Based on the intraday wind and solar load fluctuation trend, the ratio of frequency regulation dedicated capacity pool and voltage regulation shared capacity pool is dynamically adjusted: frequency regulation reserve capacity is expanded during periods of severe new energy fluctuations, and voltage regulation shared capacity is tilted during periods of high voltage deviation, to achieve the macro-optimal allocation of reusable resources across the entire network; then, a multi-objective model prediction and optimization model is constructed with the objectives of minimizing node voltage deviation, minimizing system frequency fluctuation, minimizing the overall cost of network regulation, and minimizing equipment operation losses. The apparent power constraints of each device, energy storage SOC constraints, load adjustable range, and traditional equipment operation interval constraints are uniformly included in the solution boundary. Through rolling time-domain optimization, the P / Q reuse ratio of distributed power sources, energy storage charging and discharging plans, and flexible load dispatch schemes across the entire network are periodically updated to offset the trend power disturbances of new energy in advance and avoid the accumulation of continuous frequency and voltage deviations; then, regional regulation deficit information reported by each mid-level distribution area is received, and the distribution of surplus reserve resources in each region of the entire network is compared to execute cross-regional resource support scheduling. For weak distribution areas with severe frequency and voltage disturbances and depleted resources, surplus energy storage and inverter redundancy capacity from neighboring distribution areas are allocated for cross-regional power mutual assistance to balance the utilization rate of the entire network's control resources, resolve the structural contradiction of local resource shortages and overall network resource idleness, and improve the overall collaborative reuse capability. When power electronic rapid resources and flexible load resources are exhausted, and the grid still experiences continuous and steady-state frequency and voltage exceeding limits, the master station layer initiates a backup control strategy using traditional voltage regulation equipment. Based on the voltage distribution of the entire network, the OLTC tap position and the number of parallel capacitor / reactor switching groups are optimized to slowly correct the steady-state voltage deviation of the entire network. Traditional mechanical equipment is strictly limited to participate in instantaneous frequency regulation actions and only undertakes steady-state backup voltage regulation tasks, effectively reducing frequent switching of mechanical equipment and reducing equipment losses. During the global control process, the SOC status, charge and discharge times and depths of energy storage equipment across the entire network are monitored in real time. Under the premise of meeting frequency and voltage compliance constraints, the energy storage charge and discharge switching actions are smoothed to avoid frequent energy storage reversals and deep over-limit charge and discharge.With the goal of optimizing the overall network regulation economy, the system rationally allocates ancillary service revenue and regulation losses, balancing the relationship between the safe and stable operation of the power grid and equipment lifespan and maintenance costs. Every 15 minutes, a round of global optimization calculation and strategy update is completed. Based on the latest power grid operation data and prediction deviations, the regulation scheme is corrected to achieve a rolling closed loop of "prediction-optimization-scheduling-feedback-correction". The system continuously monitors indicators such as the overall network frequency and voltage qualification rate, equipment utilization rate, and renewable energy consumption rate, and completes long-term closed-loop control of the coordinated reuse regulation of voltage and frequency regulation across the entire region.

[0075] In this embodiment, relying on day-ahead and intraday wind and solar load forecasts and a 15-minute rolling optimization mechanism, it is possible to predict trending operating conditions such as large-scale renewable energy generation, sudden power output drops, and peak-valley load switching in advance. This allows for pre-optimization of the voltage and frequency regulation capacity allocation across the entire network, changing the traditional passive and lagging control mode of "disturbing first, correcting later" in the power grid. It achieves proactive control through "prediction, pre-allocation, and pre-suppression," significantly reducing persistent voltage and frequency deviations at the source and improving the steady-state stability of the distribution network. Furthermore, the top-level master station aggregates the remaining controllable resources and control deficit information from each distribution area, uniformly scheduling the entire network's voltage and frequency regulation reserve capacity pool to achieve cross-regional resource mutual support. This effectively solves the structural contradiction of severe renewable energy fluctuations, resource scarcity, and insufficient control margin in some areas, while neighboring distribution areas have idle resources. It breaks down regional control barriers, achieving maximum balanced utilization of network-wide collaborative reuse resources and improving the overall anti-disturbance capability of the entire power grid.

[0076] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for coordinated multiplexing control of voltage and frequency regulation in distribution networks under high-proportion renewable energy sources, characterized in that: The control method includes the following steps: Step S1: Preprocessing and resource modeling, collect all controllable resource parameters in the distribution network, establish the apparent power capacity constraint model of each power electronic device, and divide the daily arbitrage fixed power area, frequency regulation reserve active power area, and voltage and frequency regulation shared redundant power area. Step S2: Layered architecture construction, building a three-layer frequency and voltage collaborative multiplexing control architecture with bottom-layer local autonomy, middle-layer regional collaboration, and top-layer global coordination, distinguishing between second-level fast power electronic regulation resources and minute-level slow traditional voltage regulation resources, and setting multi-resource and multi-operating condition regulation priority rules; Step S3: Local adaptive coupling control. The bottom edge terminal collects real-time data on voltage and frequency of each node. Based on the frequency-voltage coupling droop control algorithm, it dynamically allocates active frequency regulation power and reactive voltage regulation power within the equipment capacity constraint to realize local reuse of frequency and voltage resources of a single device. Step S4: Regional collaborative optimization and control. The mid-level feeder controller takes a single feeder / distribution station area as the control unit. Based on voltage sensitivity and frequency power deficit sensitivity, it continuously optimizes the P / Q power ratio of multiple devices in the jurisdiction to realize mutual assistance and reuse of control resources in the region and synchronously link flexible loads to participate in auxiliary control. Step S5: Global rolling correction and control. Based on the day-ahead renewable energy output and load forecast data, the top-level distribution network master station pre-allocates the entire network's voltage regulation and frequency regulation reserve capacity pools. Combined with the real-time grid operation status, the proportion of the dual capacity pools is dynamically adjusted. Through the bottom-line control of traditional voltage regulation equipment, the entire process of voltage and frequency regulation of the distribution network is coordinated and reused.

2. The method for coordinated multiplexing control of voltage and frequency regulation in distribution networks under high proportion of new energy sources according to claim 1, characterized in that: The controllable resources in step S1 include distributed new energy grid-connected inverters, energy storage converters (PCS), V2G charging piles, flexible and controllable loads, and traditional discrete voltage regulation equipment.

3. The method for coordinated multiplexing control of voltage and frequency regulation in distribution networks under high proportion of new energy sources according to claim 1, characterized in that: The specific steps of step S1 are as follows: Step S11: Collect all controllable resource parameters, traverse all control units of the target distribution substation and feeder, collect static parameters in three categories, and simultaneously collect the bus voltage, system frequency and current output of each node in real time; Step S12: Standardize and preprocess multi-source monitoring data to eliminate interference from bad data and avoid distortion in subsequent optimization and droop control calculations; Step S13: Model mathematical constraints for different types of equipment; Step S14: Single device power three-zone quantization modeling, the rated apparent capacity of energy storage and distributed power sources is divided into three independent power zones, and the quantization boundary is assigned.

4. The method for coordinated multiplexing control of voltage and frequency regulation in distribution networks under high proportion of new energy sources according to claim 3, characterized in that: The three independent power ranges in step S14 are: fixed power range FM dedicated active power zone Shared redundancy area with voltage regulation and frequency regulation .

5. The method for coordinated multiplexing control of voltage and frequency regulation in distribution networks under high proportion of new energy sources according to claim 1, characterized in that: The specific priority rules for regulation in step S2 are as follows: the highest priority is given to equipment safety operation constraints, followed by node voltage compliance constraints, then distribution network frequency compliance constraints, and finally, the most economical regulation. Power electronic resources with second-level fast response prioritize frequency and voltage disturbances, while traditional OLTC and capacitor bank resources with minute-level slow response only take action as a fallback when fast resources are exhausted or frequency and voltage continuously exceed limits.

6. The method for coordinated multiplexing control of voltage and frequency regulation in distribution networks under high proportion of new energy sources according to claim 1, characterized in that: The coupling equation of the frequency-voltage coupling droop control algorithm in step S3 is as follows: , ,in, , These represent the initial active and reactive power outputs of the equipment. This is the frequency droop coefficient. This is the voltage droop factor. , These are the system's real-time frequency and rated frequency, respectively. , These are the node's real-time voltage and rated voltage, respectively.

7. The method for coordinated multiplexing control of voltage and frequency regulation in distribution networks under high proportion of new energy sources according to claim 1, characterized in that: The local adaptive control logic in step S3 is as follows: when the voltage exceeds the limit and the frequency is normal, all redundant capacity of the equipment will prioritize the output of reactive power to participate in voltage regulation, while the active power output will remain unchanged from the initial value. When the frequency exceeds the limit but the voltage is normal, the redundant active capacity of the equipment participates in frequency regulation, and the reactive power output remains unchanged at the current value. When frequency and voltage synchronization exceeds the limit, the redundant capacity of the equipment is dynamically split according to the preset weight, and the active frequency regulation and reactive voltage regulation power are allocated synchronously to ensure that the node voltage is qualified. When the equipment capacity is exhausted and the frequency and voltage exceedance cannot be eliminated, the control deficit is reported to the upper-level area controller.

8. The method for coordinated multiplexing control of voltage and frequency regulation in distribution networks under high proportion of new energy sources according to claim 1, characterized in that: The regional collaborative optimization and control in step S4 specifically involves: for short-term power fluctuations of new energy sources at the second level, adjusting the P / Q allocation ratio of each device in the jurisdiction, and adopting a zoned control strategy that prioritizes frequency regulation of near-end energy storage and voltage regulation of far-end inverters; for continuous wind and solar power output disturbances, initiating flexible and controllable load demand response, and simultaneously reducing line voltage drop to achieve auxiliary voltage regulation by reducing active load, shifting auxiliary secondary frequency regulation, and shifting auxiliary secondary frequency regulation.

9. The method for coordinated multiplexing control of voltage and frequency regulation in distribution networks under high proportion of new energy sources according to claim 1, characterized in that: The global rolling correction and control in step S5 specifically involves: based on a 15-minute model predictive control algorithm, inputting real-time forecast data of new energy output and load, and taking the minimum node voltage deviation, minimum frequency fluctuation, and minimum overall control cost as optimization objectives, continuously optimizing the voltage and frequency regulation capacity ratio of the entire network, predicting power fluctuations in advance and pre-allocating control resources, and avoiding resource contention and control conflicts among multiple devices.

10. The method for coordinated multiplexing control of voltage and frequency regulation in distribution networks under high proportion of new energy sources according to claim 1, characterized in that: The specific steps of step S5 are as follows: Step S51: Aggregation of network-wide predictive data and assessment of operating conditions; Step S52: Dynamic pre-division of the entire network voltage and frequency regulation dual capacity pool; Step S53: Multi-objective model prediction and rolling optimization solution; Step S54: Cross-regional resource sharing and overall coordination; Step S55: Traditional slow-speed equipment as a backup and coordinated control; Step S56: Coordinated correction of energy storage lifetime and economic constraints; Step S57: Periodic rolling updates and closed-loop archiving across the entire network.

Images