Multi-time-scale voltage regulation method and device for high, medium and low-voltage power distribution network

Abstract

The invention provides a multi-time-scale voltage regulation method and device for a high, medium and low-voltage power distribution network. The method comprises the steps of determining a ratio of active power to load of a distributed photovoltaic cluster according to a day-ahead short-term load predicted value of the power distribution network and an active power predicted value of the distributed photovoltaic cluster; determining a voltage estimation value of the preset node according to the resistance value and the reactance value from the low-voltage side of the transformer substation to the preset node, the rated voltage of the medium-voltage feeder, and the net active power and the net reactive power from the low-voltage side of the transformer substation to the preset node; according to the node voltage upper limit value of the preset node and the reactive power maximum adjustable value of the medium-voltage distributed photovoltaic system under the overvoltage working condition, determining a voltage predicted value of the preset node after the voltage of the grid-connected point is reduced by using the photovoltaic inverter; and adjusting the reactive power of the medium-voltage distributed photovoltaic by using the high-medium-low voltage power distribution network coordinated regulation model so as to regulate the voltage of the high-medium-low voltage power distribution network. According to the invention, multi-time-scale voltage regulation of the high-medium and low-voltage power distribution network can be carried out.

Description

Technical Field

[0001] The present application relates to the field of power system maintenance, and specifically to a multi-time-scale voltage regulation method and device for high, medium, and low voltage distribution networks. Background Technique

[0002] With the high-penetration access of distributed photovoltaic into medium and low voltage distribution networks, the problems of voltage over-limit and power flow reverse transmission in the distribution network are becoming increasingly serious. Utilizing the reactive power regulation ability of distributed photovoltaic inverters to alleviate overvoltage has become an important solution.

[0003] For the optimal regulation and control of distribution networks with distributed photovoltaic, the traditional research object is the medium voltage feeder. The model of the upper-level substation and the specific structure of the source-network-load inside the substation area are simplified, and an optimization model with a constant voltage at the root node of the feeder is constructed. With the full penetration of distributed photovoltaic in medium and low voltage distribution networks, the requirement for multi-level coordination is becoming more and more urgent. Simply constructing a medium voltage feeder model is difficult to meet the needs of multi-voltage level coordination.

[0004] This section aims to provide background or context for the embodiments of the present invention described in the claims. The description here is not admitted to be prior art just because it is included in this section. Summary of the Invention

[0005] Aiming at the problems in the prior art, the present application provides a multi-time-scale voltage regulation method and device for high, medium, and low voltage distribution networks, which can comprehensively consider the slow-action on-load tap-changing transformers, medium voltage distributed photovoltaic power stations with good communication conditions, and low voltage distributed photovoltaic with weak communication conditions, construct a coordinated regulation and control model for high, medium, and low voltage distribution networks, and perform multi-time-scale voltage regulation on high, medium, and low voltage distribution networks.

[0006] To solve the above technical problems, the present application provides the following technical solutions:

[0007] In a first aspect, the present application provides a multi-time-scale voltage regulation method for high, medium, and low voltage distribution networks, including:

[0008] Determine the ratio of the active power of the distributed photovoltaic cluster to the load according to the day-ahead short-term load prediction value of the distribution network and the predicted active power value of the distributed photovoltaic cluster in the distribution network; wherein, the distributed photovoltaic cluster includes medium voltage distributed photovoltaic and low voltage distributed photovoltaic;

[0009] Determine the voltage estimation value of the preset node according to the resistance value and reactance value from the low voltage side of the substation in the distribution network to the preset node, the rated voltage of the medium voltage feeder, the net active power and net reactive power from the low voltage side of the substation to the preset node;

[0010] If the ratio exceeds the ratio threshold and the voltage estimation value exceeds the upper limit of the node voltage allowed by the distribution network, evaluate the reactive power adequacy of the medium-voltage feeder according to the upper limit of the node voltage of the preset node and the maximum adjustable reactive power value of the medium-voltage distributed photovoltaic under overvoltage conditions, and obtain the voltage prediction value of the preset node after using the photovoltaic inverter to reduce the grid connection point voltage;

[0011] If the voltage prediction value still exceeds the upper limit of the node voltage allowed by the distribution network, use the pre-constructed coordinated regulation model of high, medium and low voltage distribution networks to adjust the reactive power of the medium-voltage distributed photovoltaic to regulate the voltage of the high, medium and low voltage distribution networks.

[0012] Further, the determining the ratio of the active power of the distributed photovoltaic cluster to the load according to the day-ahead short-term load prediction value of the distribution network and the active power prediction value of the distributed photovoltaic cluster in the distribution network includes:

[0013] Calculate the active power prediction value of the distributed photovoltaic cluster according to the number of medium-voltage distributed photovoltaics, the number of low-voltage distributed photovoltaics, the active power prediction values of each medium-voltage distributed photovoltaic and the active power prediction values of each low-voltage distributed photovoltaic;

[0014] Calculate the day-ahead short-term load prediction value according to the number of loads and the active power prediction values of each load;

[0015] Determine the ratio of the active power prediction value of the distributed photovoltaic cluster to the day-ahead short-term load prediction value as the ratio of the active power to the load.

[0016] Further, the determining the voltage estimation value of the preset node according to the resistance value and reactance value from the low-voltage side of the substation in the distribution network to the preset node, the rated voltage of the medium-voltage feeder, the net active power and net reactive power from the low-voltage side of the substation to the preset node includes:

[0017] Calculate the first subtrahend according to the voltage value of the high-voltage side of the substation in the distribution network and the transformer ratio of the substation transformer;

[0018] Calculate the second subtrahend according to the resistance value and reactance value, the net active power and net reactive power, and the rated voltage of the medium-voltage feeder;

[0019] Determine the difference between the first subtrahend and the first subtrahend as the voltage estimation value.

[0020] Further, the evaluating the reactive power adequacy of the medium-voltage feeder according to the upper limit of the node voltage of the preset node and the maximum adjustable reactive power value of the medium-voltage distributed photovoltaic under overvoltage conditions, and obtaining the voltage prediction value of the preset node after using the photovoltaic inverter to reduce the grid connection point voltage includes:

[0021] Determine the maximum adjustable value of the reactive power according to the rated capacity and rated power of the medium-voltage distributed photovoltaic;

[0022] Determine the third subtrahend according to the maximum adjustable value of the reactive power and the change in the preset node voltage caused by the change in the unit reactive power of the medium-voltage distributed photovoltaic;

[0023] Determine the voltage prediction value as the difference between the upper limit of the node voltage of the preset node and the third subtrahend.

[0024] Further, if the voltage prediction value still exceeds the upper limit of the node voltage allowed by the distribution network, adjust the reactive power of the medium-voltage distributed photovoltaic by using the pre-constructed coordinated regulation model of the high, medium, and low voltage distribution networks, including:

[0025] Construct the objective function of the coordinated regulation model of the high, medium, and low voltage distribution networks according to the number of medium-voltage nodes in the distribution network, the current amplitude between nodes, and the line impedance;

[0026] Construct the on-load tap-changer constraint according to the voltage value on the low-voltage side of the substation, the transformer ratio of the substation transformer, the change in the transformer tap position of the substation, and the adjustment step of the on-load tap-changer;

[0027] Construct the constraints of the medium-voltage distributed photovoltaic power station according to the predicted apparent power value, predicted active power value, predicted reactive power value, and minimum power factor of the medium-voltage distributed photovoltaic;

[0028] Construct the power balance constraint according to the set of all branch head nodes with the set node as the end node, the set of all branch end nodes with the set node as the head node, the net injection of active power and reactive power at the set node, the node voltage of the set node, the predicted active power value of the medium-voltage distributed photovoltaic, and the predicted active power value of the low-voltage distributed photovoltaic;

[0029] Construct the node voltage constraint according to the lower limit of the node voltage allowed by the distribution network and the upper limit of the node voltage allowed by the distribution network;

[0030] Construct the line current-carrying capacity constraint according to the maximum current-carrying capacity between nodes;

[0031] Solve the optimal solution of the objective function under the on-load tap-changer constraint, the constraints of the medium-voltage distributed photovoltaic power station, the power balance constraint, the node voltage constraint, and the line current-carrying capacity constraint to obtain the reactive power adjustment amount of the medium-voltage distributed photovoltaic.

[0032] Further, after regulating the reactive power of the medium-voltage distributed photovoltaic by using the pre-constructed coordinated regulation model of the high, medium, and low-voltage distribution networks, the multi-time scale voltage regulation method for the high, medium, and low-voltage distribution networks further includes:

[0033] Determine the reactive power change amount of the low-voltage distributed photovoltaic according to the measured voltage value of the low-voltage distributed photovoltaic, the local voltage control coefficient, and the upper limit of the node voltage allowed by the distribution network, so as to regulate the high, medium, and low-voltage distribution networks.

[0034] In a second aspect, the present application provides a multi-time scale voltage regulation device for a high, medium, and low-voltage distribution network, including:

[0035] A power load ratio determination unit for determining the ratio of the active power of the distributed photovoltaic cluster to the load according to the day-ahead short-term load forecast value of the distribution network and the active power forecast value of the distributed photovoltaic cluster in the distribution network; wherein, the distributed photovoltaic cluster includes a medium-voltage distributed photovoltaic and a low-voltage distributed photovoltaic;

[0036] A voltage estimate generation unit for determining the voltage estimate of the preset node according to the resistance value and reactance value from the low-voltage side of the substation in the distribution network to the preset node, the rated voltage of the medium-voltage feeder, the net active power and net reactive power from the low-voltage side of the substation to the preset node;

[0037] A voltage prediction value generation unit for, if the ratio exceeds the ratio threshold and the voltage estimate exceeds the upper limit of the node voltage allowed by the distribution network, evaluating the reactive power adequacy of the medium-voltage feeder according to the upper limit of the node voltage of the preset node and the maximum adjustable value of the reactive power of the medium-voltage distributed photovoltaic under overvoltage conditions, and obtaining the voltage prediction value of the preset node after reducing the grid connection point voltage by using the photovoltaic inverter;

[0038] A coordinated centralized voltage regulation unit for, if the voltage prediction value still exceeds the upper limit of the node voltage allowed by the distribution network, regulating the reactive power of the medium-voltage distributed photovoltaic by using the pre-constructed coordinated regulation model of the high, medium, and low-voltage distribution networks, so as to regulate the high, medium, and low-voltage distribution networks.

[0039] Further, the power load ratio determination unit includes:

[0040] A power prediction value determination module for calculating the active power prediction value of the distributed photovoltaic cluster according to the number of the medium-voltage distributed photovoltaic, the number of the low-voltage distributed photovoltaic, the active power prediction value of each medium-voltage distributed photovoltaic, and the active power prediction value of each low-voltage distributed photovoltaic;

[0041] A load prediction value determination module for calculating the day-ahead short-term load forecast value according to the number of the loads and the active power forecast value of each load;

[0042] A power load ratio determination module, configured to determine the ratio of the predicted active power value of the distributed photovoltaic cluster to the short-term load prediction value for the day-ahead as the ratio of the active power to the load.

[0043] Further, the voltage estimation value generation unit includes:

[0044] A first subtraction number determination module, configured to calculate a first subtraction number according to the voltage value on the high-voltage side of the substation in the distribution network and the transformer ratio of the substation transformer;

[0045] A second subtraction number determination module, configured to calculate a second subtraction number according to the resistance value and reactance value, the net active power and net reactive power, and the rated voltage of the medium-voltage feeder;

[0046] A voltage estimation value generation module, configured to determine the difference between the first subtraction number and the first subtraction number as the voltage estimation value.

[0047] Further, the voltage prediction value generation unit includes:

[0048] A maximum adjustable value determination module, configured to determine the maximum adjustable value of the reactive power according to the rated capacity and rated power of the medium-voltage distributed photovoltaic;

[0049] A third subtraction number determination module, configured to calculate a third subtraction number according to the maximum adjustable value of the reactive power and the change amount of the preset node voltage caused by the change amount of the unit reactive power of the medium-voltage distributed photovoltaic;

[0050] A voltage prediction value generation module, configured to determine the difference between the upper limit of the node voltage of the preset node and the third subtraction number as the voltage prediction value.

[0051] Further, the collaborative centralized voltage regulation unit includes:

[0052] An objective function establishment module, configured to construct an objective function of the coordinated regulation model of the high, medium, and low voltage distribution networks according to the number of medium-voltage nodes in the distribution network, the current amplitude between nodes, and the line impedance;

[0053] A transformer voltage regulation constraint construction module, configured to construct a on-load tap-changer transformer constraint according to the voltage value on the low-voltage side of the substation, the transformer ratio of the substation transformer, the change amount of the transformer tap position, and the adjustment step of the on-load tap-changer;

[0054] A photovoltaic constraint construction module, configured to construct a medium-voltage distributed photovoltaic power station constraint according to the predicted apparent power value, predicted active power value, predicted reactive power value, and minimum power factor of the medium-voltage distributed photovoltaic;

[0055] A balance constraint construction module, configured to construct a power balance constraint according to a set of all branch head nodes with a set node as the end node, a set of all branch end nodes with the set node as the head node, the net active power injection and net reactive power injection of the set node, the node voltage of the set node, the predicted active power of the medium-voltage distributed photovoltaic, and the predicted active power of the low-voltage distributed photovoltaic;

[0056] A voltage constraint construction module, configured to construct a node voltage constraint according to the lower limit of the node voltage allowed by the distribution network and the upper limit of the node voltage allowed by the distribution network;

[0057] A flow constraint construction module, configured to construct a line current-carrying capacity constraint according to the maximum current-carrying capacity between nodes;

[0058] A first centralized voltage regulation module, configured to solve the optimal solution of the objective function under the on-load tap-changer constraint, the medium-voltage distributed photovoltaic power station constraint, the power balance constraint, the node voltage constraint, and the line current-carrying capacity constraint to obtain the reactive power regulation amount of the medium-voltage distributed photovoltaic.

[0059] Further, the multi-time scale voltage regulation device for high, medium, and low voltage distribution networks further includes:

[0060] A collaborative decentralized voltage regulation unit, configured to determine the reactive power change amount of the low-voltage distributed photovoltaic according to the measured voltage value of the low-voltage distributed photovoltaic, the local voltage control coefficient, and the upper limit of the node voltage allowed by the distribution network, so as to regulate the high, medium, and low voltage distribution networks.

[0061] In a third aspect, the present application provides an electronic device including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the steps of the multi-time scale voltage regulation method for high, medium, and low voltage distribution networks are implemented.

[0062] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the multi-time scale voltage regulation method for high, medium, and low voltage distribution networks are implemented.

[0063] In a fifth aspect, the present application provides a computer program product, including a computer program / instructions. When the computer program / instructions are executed by a processor, the steps of the multi-time scale voltage regulation method for high, medium, and low voltage distribution networks are implemented.

[0064] In view of the problems in the prior art, the multi-time scale voltage regulation method and device for high, medium and low voltage distribution networks provided by this application can consider the differences in measurement and communication configurations of different voltage levels in the distribution network, incorporate adjustable resources with different action time scales into different optimization time scales, and construct a coordinated control model for high, medium and low voltage distribution networks, also known as the multi-time scale voltage regulation model for high, medium and low voltage distribution networks; for high and medium voltage distribution networks with the functions of "remote measurement", "remote signaling" and "remote regulation", a centralized control method is adopted to regulate adjustable resources by establishing a centralized optimization model. For low voltage distribution networks with only weak measurement capabilities, a decentralized local control method for low voltage distributed photovoltaics is adopted for regulation; considering the decisive influence of substation voltage on the power flow distribution of medium and low voltage distribution networks, the tap positions of on-load tap-changers in substations are incorporated into the coordinated control model of high, medium and low voltage distribution networks, fully considering the physical constraints of the tap action times and action time of the transformer, and reducing the number of calculations in the centralized control stage of the regulation process through two judgments. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0066] Figure 1 It is a flowchart of the multi-time scale voltage regulation method for high, medium and low voltage distribution networks in the embodiments of this application;

[0067] Figure 2 It is a flowchart of determining the ratio of the active power of a distributed photovoltaic cluster to the load in the embodiments of this application;

[0068] Figure 3 It is a flowchart of determining the voltage estimation value of a preset node in the embodiments of this application;

[0069] Figure 4 It is a flowchart of obtaining the voltage prediction value of a preset node after using a photovoltaic inverter to reduce the voltage at the grid connection point in the embodiments of this application;

[0070] Figure 5 It is a flowchart of regulating the reactive power of medium voltage distributed photovoltaics in the embodiments of this application;

[0071] Figure 6 It is a structural diagram of the multi-time scale voltage regulation device for high, medium and low voltage distribution networks in the embodiments of this application;

[0072] Figure 7 It is a structural diagram of the power load ratio determination unit in the embodiments of this application;

[0073] Figure 8 The structure diagram of the voltage estimation value generation unit in the embodiment of the present application;

[0074] Figure 9 The structure diagram of the voltage prediction value generation unit in the embodiment of the present application;

[0075] Figure 10 The structure diagram of the collaborative centralized voltage regulation unit in the embodiment of the present application;

[0076] Figure 11 The schematic structural diagram of the electronic device in the embodiment of the present application;

[0077] Figure 12 The schematic diagram of different control time scales in the embodiment of the present application;

[0078] Figure 13 The flow chart of the multi-time scale voltage regulation algorithm for high, medium and low voltage distribution networks in the embodiment of the present application. Specific embodiments

[0079] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer and more understandable, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but do not limit the present invention.

[0080] The information collected in the technical solution of the present application is information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of relevant data, etc., all comply with the relevant laws, regulations and standards of relevant countries and regions, take necessary confidentiality measures, do not violate public order and good customs, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0081] Provide corresponding operation entrances for users to choose to agree or refuse the results of automated decision-making; if the user chooses to refuse, enter the expert decision-making process.

[0082] In one embodiment, see Figure 1 , in order to comprehensively consider the slow-motion on-load tap-changer of the transformer, the medium-voltage distributed photovoltaic power station with good communication conditions, and the low-voltage distributed photovoltaic with weak communication conditions, build a collaborative regulation model for high, medium and low voltage distribution networks, and perform multi-time scale voltage regulation on high, medium and low voltage distribution networks, the present application provides a multi-time scale voltage regulation method for high, medium and low voltage distribution networks, including:

[0083] S101: Determine the ratio of the active power of the distributed photovoltaic cluster to the load according to the day-ahead short-term load forecast value of the distribution network and the predicted active power value of the distributed photovoltaic cluster in the distribution network; wherein, the distributed photovoltaic cluster includes medium-voltage distributed photovoltaics and low-voltage distributed photovoltaics;

[0084] S102: Determine the voltage estimation value of the preset node according to the resistance value and reactance value from the low-voltage side of the substation in the distribution network to the preset node, the rated voltage of the medium-voltage feeder, the net active power and net reactive power from the low-voltage side of the substation to the preset node;

[0085] S103: If the ratio exceeds the ratio threshold and the voltage estimation value exceeds the upper limit of the node voltage allowed by the distribution network, evaluate the reactive power adequacy of the medium-voltage feeder according to the upper limit of the node voltage of the preset node and the maximum adjustable value of the reactive power of the medium-voltage distributed photovoltaics under overvoltage conditions, and obtain the voltage prediction value of the preset node after using the photovoltaic inverter to reduce the grid connection point voltage;

[0086] S104: If the voltage prediction value still exceeds the upper limit of the node voltage allowed by the distribution network, use the pre-constructed coordinated regulation model of high, medium and low voltage distribution networks to adjust the reactive power of the medium-voltage distributed photovoltaics to regulate the voltage of high, medium and low voltage distribution networks.

[0087] It can be understood that the embodiments of the present application comprehensively consider the regulation resources on the high-voltage side, medium-voltage side and low-voltage side, comprehensively consider the slow-acting on-load tap-changing transformer taps, medium-voltage distributed photovoltaic power stations with good communication conditions and low-voltage distributed photovoltaics with weak communication conditions, and construct a coordinated regulation model of high, medium and low voltage distribution networks (also known as a multi-time scale voltage regulation model of high, medium and low voltage distribution networks). The coordinated regulation process of high, medium and low voltage distribution networks includes a centralized regulation stage (which can be used to regulate medium-voltage distributed photovoltaics) and a decentralized regulation stage (used to regulate low-voltage distributed photovoltaics). Medium-voltage distributed photovoltaics can be connected to the high-voltage distribution network and the medium-voltage distribution network, and low-voltage distributed photovoltaics can be connected to the medium-voltage distribution network and the low-voltage distribution network. By adjusting the voltages of medium-voltage distributed photovoltaics and low-voltage distributed photovoltaics, the voltage regulation of high, medium and low voltage distribution networks can be achieved.

[0088] The multi-time scale voltage regulation strategy for high, medium and low voltage distribution networks provided by the present application mainly includes the following steps: ① Data initialization; ② Calculate the ratio of the active power of the distributed photovoltaic cluster (including medium-voltage distributed photovoltaics and low-voltage distributed photovoltaics) to the load; ③ Calculate the voltage estimation value of the medium-voltage distributed photovoltaics; ④ Execute the pre-judgment of transformer tap adjustment; ⑤ Execute the evaluation of reactive power adequacy of the medium-voltage feeder; ⑥ Execute the re-judgment of transformer tap adjustment; ⑦ Establish an optimal power flow model within the centralized regulation period, which takes the minimum network loss as the objective function and can satisfy multiple constraint conditions at the same time; ⑧ Execute the decentralized in-situ control of low-voltage distributed photovoltaics.

[0089] See Figure 12 The embodiments of the present application involve the optimized regulation of high-voltage, medium-voltage, and low-voltage levels, including two time scales. Definition: The time scale of short-term load prediction and distributed photovoltaic short-term power prediction for the day-ahead is ΔT, that is, the time scale of centralized regulation (also known as centralized optimization) is ΔT, and the time scale of decentralized regulation (also known as decentralized optimization) for low-voltage distributed photovoltaic (local) is Δt. Within a centralized regulation time interval ΔT, it can be further divided into several more subtle local control time scales Δt.

[0090] The present invention fully considers the differences in measurement and communication configurations of different voltage levels in the distribution network, establishes different control strategies for adjustable resources in high- and medium-voltage distribution networks and low-voltage distribution networks, and also considers the differences in the action time scales of different adjustable resources. The proposed voltage regulation control strategy can give full play to the reactive power regulation ability of on-load tap-changing transformers, medium-voltage distributed photovoltaic power stations, and small-capacity low-voltage distributed photovoltaics and the regulation ability for the global power flow, and avoids the calculation times of the optimal power flow in rolling optimization by performing pre-judgment on the adjustment of transformer tap positions.

[0091] As can be seen from the above description, the multi-time-scale voltage regulation method for high-, medium-, and low-voltage distribution networks provided by the present application can consider the differences in measurement and communication configurations of different voltage levels in the distribution network, incorporate adjustable resources with different action time scales into different optimization time scales, and construct a coordinated regulation model for high-, medium-, and low-voltage distribution networks, also known as a multi-time-scale voltage regulation model for high-, medium-, and low-voltage distribution networks; for high- and medium-voltage distribution networks with the functions of "remote measurement", "remote signaling", and "remote adjustment", a centralized control method is adopted to regulate adjustable resources by establishing a centralized optimization model. For low-voltage distribution networks with only weak measurement capabilities, a decentralized local control method for low-voltage distributed photovoltaics is adopted for regulation; considering the decisive influence of substation voltage on the power flow distribution of medium- and low-voltage distribution networks, the tap positions of on-load tap-changing transformers in substations are incorporated into the coordinated regulation model for high-, medium-, and low-voltage distribution networks, fully considering the physical constraints of the number of transformer tap operations and the action time, and reducing the calculation times in the centralized regulation stage of the regulation process through two judgments.

[0092] In one embodiment, see Figure 2 The determination of the ratio of the active power of the distributed photovoltaic cluster to the load according to the day-ahead short-term load prediction value of the distribution network and the predicted active power value of the distributed photovoltaic cluster in the distribution network includes:

[0093] S201: Calculate the predicted active power value of the distributed photovoltaic cluster according to the number of medium-voltage distributed photovoltaics, the number of low-voltage distributed photovoltaics, the predicted active power values of each medium-voltage distributed photovoltaic, and the predicted active power values of each low-voltage distributed photovoltaic;

[0094] S202: Calculate the day-ahead short-term load forecast value according to the number of the loads and the predicted active power values of the loads.

[0095] S203: Determine the ratio of the predicted active power of the distributed photovoltaic cluster to the day-ahead short-term load forecast value as the ratio of the active power to the load.

[0096] It can be understood that during the initialization of step ①, it is first necessary to obtain the topological structure of the distribution network, line parameters, day-ahead short-term load forecast value, installed capacity and installation location of each distributed photovoltaic (including medium-voltage distributed photovoltaic and low-voltage distributed photovoltaic), historical voltage value of the medium-voltage distributed photovoltaic, predicted active power value of the medium-voltage distributed photovoltaic, and voltage curve of the high-voltage side of the substation. Suppose that in the historical record, the node with the most serious overvoltage in the medium-voltage distribution network is b max , and the corresponding voltage value is

[0097] In step ②, calculate the ratio of the active power of the distributed photovoltaic cluster to the load at the T f th moment according to the day-ahead short-term load forecast value and the predicted active power value of the medium-voltage distributed photovoltaic

[0098]

[0099] where, n PV,M is the number of medium-voltage distributed photovoltaics, n PV,L is the number of low-voltage distributed photovoltaics, n LD is the number of loads, is the predicted active power value of the Gth medium-voltage distributed photovoltaic at t = T f moment, is the predicted active power value of the gth low-voltage side distributed photovoltaic at t = T f moment, is the predicted active power value of the dth load at t = T j moment. Considering that the low-voltage distributed photovoltaic lacks necessary meteorological information, the capacity reduction method can be used for acquisition.

[0100] From the above description, it can be seen that the multi-time scale voltage regulation method for high, medium and low voltage distribution networks provided by this application can determine the ratio of the active power of the distributed photovoltaic cluster to the load according to the day-ahead short-term load forecast value of the distribution network and the predicted active power value of the distributed photovoltaic cluster in the distribution network.

[0101] In one embodiment, see Figure 3, determining the voltage estimation value of the preset node according to the resistance value and reactance value from the low-voltage side of the substation in the distribution network to the preset node, the rated voltage of the medium-voltage feeder, and the net active power and net reactive power from the low-voltage side of the substation to the preset node, includes:

[0102] S301: Calculate the first subtrahend according to the voltage value of the high-voltage side of the substation in the distribution network and the transformer ratio of the substation transformer;

[0103] S302: Calculate the second subtrahend according to the resistance value and reactance value, the net active power and net reactive power, and the rated voltage of the medium-voltage feeder;

[0104] S303: Determine the difference between the first subtrahend and the first subtrahend as the voltage estimation value.

[0105] It can be understood that in step ③, rolling optimization needs to be carried out within the time interval of the distributed photovoltaic output. Let the time interval when the distributed photovoltaic output is not 0 be [T f , T e . Let t = T f . Obtain the ultra-short-term load prediction value and the ultra-short-term power prediction value of the medium-voltage distributed photovoltaic, and calculate the voltage estimation value of node b f+1 at the moment of t = T max .

[0106]

[0107] Among them, is the voltage estimation value of node b f+1 at the moment of t = T max , is the transformer ratio of the substation transformer at the moment of t = T f , is the voltage of the high-voltage side of the substation at the moment of t = T f , and are the resistance and reactance values from the low-voltage side of the substation to node b max , and u0 is the rated voltage of the medium-voltage feeder. and are respectively the net active power and net reactive power of the distribution network area from the low-voltage side of the substation to node b max , and can be calculated according to the ultra-short-term power prediction of the load and medium-voltage distributed photovoltaic at t = T f+1 . The calculation formula is as follows:

[0108]

[0109] Among them, n1 is the number of loads in the distribution network area from the low-voltage side of the substation to node b max , and n2 is from the low-voltage side of the substation to node bmax The number of distributed photovoltaics in the feeder area, including medium-voltage distributed photovoltaics and low-voltage distributed photovoltaics, is at time t = T f+1 The predicted active power value of the d-th load at time is at time t = T f+1 The predicted active power value of the a-th distributed photovoltaic at time, including medium-voltage distributed photovoltaics and low-voltage distributed photovoltaics, is at time t = T f+1 The estimated reactive power value of the d-th load at time.

[0110] As can be seen from the above description, the multi-time-scale voltage regulation method for high, medium, and low voltage distribution networks provided by this application can determine the voltage estimation value of the preset node according to the resistance value and reactance value from the low-voltage side of the substation in the distribution network to the preset node, the rated voltage of the medium-voltage feeder, and the net active power and net reactive power from the low-voltage side of the substation to the preset node.

[0111] In one embodiment, referring to Figure 4 , evaluating the reactive power adequacy of the medium-voltage feeder according to the node voltage upper limit of the preset node and the maximum adjustable reactive power value of the medium-voltage distributed photovoltaic under overvoltage conditions, and obtaining the voltage prediction value of the preset node after using the photovoltaic inverter to reduce the grid connection point voltage, includes:

[0112] S401: Determine the maximum adjustable reactive power value according to the rated capacity and rated power of the medium-voltage distributed photovoltaic;

[0113] S402: Determine the third subtraction according to the maximum adjustable reactive power value and the change in the preset node voltage caused by the change in the unit reactive power of the medium-voltage distributed photovoltaic;

[0114] S403: Determine the difference between the node voltage upper limit of the preset node and the third subtraction as the voltage prediction value.

[0115] It can be understood that in step ④, it is first necessary to perform a pre-judgment on the adjustment of the transformer tap.

[0116] If the following two conditions are simultaneously met, that is: t = T f+1 The ratio of the active power of the distributed photovoltaic to the load at time is greater than 1 and the voltage estimation value of node b max exceeds the node voltage upper limit allowed by the distribution network, the calculation process transfers to step ⑤, and then steps ⑥, ⑦, and ⑧ are executed. If either of the two conditions is not met, the process directly transfers to step ⑦, and then step ⑧ is executed.

[0117] Condition 1:

[0118] Condition 2:

[0119] Among them, is the ratio of the active power of the distributed PV cluster at the T-th f+1 moment to the load, is the estimated voltage value of node b f+1 at the moment t = T, max and U H is the upper limit of the node voltage allowed by the distribution network.

[0120] Next, step ⑤ is executed to evaluate the reactive power adequacy of the medium-voltage feeder.

[0121] Based on the data of the ultra-short-term power prediction, it is estimated that node b max will have a situation of over-voltage upper limit in the next rolling optimization cycle. The purpose of executing step ⑤ is to determine the voltage of node b max after reducing the grid connection point voltage by consuming reactive power of the PV inverter without adjusting the transformer tap:

[0122]

[0123] Among them, the node with the most serious over-voltage in the medium-voltage distribution network is b max , and the corresponding voltage value is n PV is the total number of distributed PVs in the distribution network, n PV = n PV,M + n PV,L , is the change in the voltage of node b max caused by the change in the reactive power of the a-th distributed PV unit, and Q PV,max,a is the maximum adjustable value of the reactive power of the a-th distributed PV under the most serious over-voltage condition. The calculation formula of Q PV,max,a is:

[0124]

[0125] Among them, S PV,a is the rated capacity of the a-th distributed PV, and

[0126] is the rated power of the a-th distributed PV.

[0127] In one embodiment, seeFigure 5 If the predicted voltage value still exceeds the upper limit of the node voltage allowed by the distribution network, the reactive power of the medium-voltage distributed photovoltaic is adjusted by using the pre-constructed coordinated regulation model of the high, medium and low voltage distribution networks, including:

[0128] S501: Construct the objective function of the coordinated regulation model of the high, medium and low voltage distribution networks according to the number of medium-voltage nodes in the distribution network, the current amplitude between nodes and the line impedance;

[0129] S502: Construct the on-load tap-changer constraint according to the voltage value at the low-voltage side of the substation, the transformer ratio of the substation transformer, the change amount of the substation transformer tap position and the adjustment step of the on-load tap-changer;

[0130] S503: Construct the constraint of the medium-voltage distributed photovoltaic power station according to the predicted apparent power value, the predicted active power value, the predicted reactive power value and the minimum power factor of the medium-voltage distributed photovoltaic;

[0131] S504: Construct the power balance constraint according to the set of all branch head nodes with the set node as the end node, the set of all branch end nodes with the set node as the head node, the net injection amount of active power and reactive power of the set node, the node voltage of the set node, the predicted active power value of the medium-voltage distributed photovoltaic and the predicted active power value of the low-voltage distributed photovoltaic;

[0132] S505: Construct the node voltage constraint according to the lower limit of the node voltage allowed by the distribution network and the upper limit of the node voltage allowed by the distribution network;

[0133] S506: Construct the line current-carrying capacity constraint according to the maximum current-carrying capacity between nodes;

[0134] S507: Solve the optimal solution of the objective function under the on-load tap-changer constraint, the medium-voltage distributed photovoltaic power station constraint, the power balance constraint, the node voltage constraint and the line current-carrying capacity constraint to obtain the reactive power adjustment amount of the medium-voltage distributed photovoltaic.

[0135] It can be understood that in step ⑥, the transformer tap adjustment judgment is performed again.

[0136] If (that is, the predicted voltage value still exceeds the upper limit of the node voltage allowed by the distribution network), and at the same time, the following conditions are met: 1) The daily adjustment times of the transformer tap are less than the upper limit of the adjustment times in a day; 2) The time interval between two adjacent transformer tap adjustments is greater than the set time threshold, then the transformer tap is adjusted downward by 1 gear. Otherwise, the transformer tap is not adjusted.

[0137] In step ⑦, the intraday centralized regulation is carried out.

[0138] In this embodiment, an optimal power flow model is established with the minimum network loss (P loss ) within the rolling period as the objective function. The decision variable is the reactive power regulation amount of the medium-voltage distributed photovoltaic.

[0139] Objective function:

[0140] where N b is the number of nodes in the medium-voltage distribution network, is the current amplitude of the line between node b i and node b j at time t = T f+1 , R ij is the resistance of the line between node b i and node b j .

[0141] Constraints include:

[0142] 1) On-load tap-changer (OLTC) constraint:

[0143]

[0144] where is the low-voltage side voltage of the substation at time t = T f , is the high-voltage side voltage of the substation at time t = T f , and are the transformer turns ratios of the substation at times t = T f and t = T f-1 respectively, Δn is the transformer tap change amount, and K is the regulation step of the OLTC.

[0145] 2) Medium-voltage distributed photovoltaic power station constraint

[0146] Without considering the curtailment of medium-voltage distributed photovoltaic power, its constraints are as follows:

[0147]

[0148] where is the reactive power adjustment amount of the Gth medium-voltage distributed photovoltaic at time t = T j , S PV,M,G is the rated power of the Gth medium-voltage distributed photovoltaic, the predicted active power value of the Gth medium-voltage distributed photovoltaic at time t = T j , is the minimum power factor of the medium-voltage distributed photovoltaic, which can be set to 0.98.

[0149] 3) Power balance constraint

[0150]

[0151] In the power balance constraint, the detailed topology of the low - voltage distribution network is not considered, and only the net power of the low - voltage distributed photovoltaics and low - voltage users is considered as the power injection of the medium - voltage nodes. The power flow equation is the DistFlow model, where, represents the set of all branch head nodes with b j as the end node, represents the set of all branch end nodes with b j as the head node, b i is the i - th node, b j is the j - th node, d j is the d j - th load node connected to node b j a j is the a j - th distributed photovoltaic connected to node b j G j is the G j - th medium - voltage distributed photovoltaic connected to node b j , is the active power on the line connecting node b f and node b i at time t = T j , is the reactive power on the line connecting node b f and node b i at time t = T j , R ij is the resistance of the line between node b i and node b j , X ij is the reactance of the line between node b i and node b j , is the current on the line connecting node b f and node b i at time t = T j , is the active power at the head of branch jl at time t = T f , is the reactive power at the head of branch jl at time t = T f , is the net active power injection of node b f at time t = T j , is the net active power injection of node b f at time t = T jThe net reactive power injection at time t = T f is the voltage of node b i ; at time t = T f is the voltage of node b j ; at time t = T f is the predicted active power of the d j -th load at time t = T f is the estimated reactive power of the d j -th load at time t = T f is the predicted active power of the a j -th distributed PV, including the predicted active powers of medium-voltage and low-voltage distributed PVs at time t = T f is the reactive power regulation amount of the G j -th medium-voltage distributed PV

[0152] 4) Node voltage constraint

[0153]

[0154] where U L is the lower limit of the node voltage allowed in the distribution network, and the meanings of other symbols are as described above

[0155] 5) Line current-carrying capacity constraint

[0156]

[0157] where is the current on the line connecting node b i and node b j ; is the maximum current-carrying capacity of the line between node b i and node b j

[0158] As can be seen from the above description, the multi-time scale voltage regulation method for high, medium, and low voltage distribution networks provided by this application can adjust the reactive power of the medium-voltage distributed PV by using the pre-constructed coordinated control model of high, medium, and low voltage distribution networks if the predicted voltage still exceeds the upper limit of the node voltage allowed in the distribution network

[0159] In one embodiment, after adjusting the reactive power of the medium-voltage distributed PV by using the pre-constructed coordinated control model of high, medium, and low voltage distribution networks, it further includes

[0160] ​Determine the reactive power change amount of the low-voltage distributed PV according to the measured voltage value of the low-voltage distributed PV, the local voltage control coefficient (also known as the in-situ voltage control coefficient), and the upper limit of the node voltage allowed by the distribution network, so as to regulate the voltage of the high, medium, and low-voltage distribution networks.

[0161] It can be understood that in step ⑧, the decentralized in-situ control of the low-voltage distributed PV is executed.

[0162] Due to the lack of measurement and communication conditions, the low-voltage distributed PV adopts an in-situ decentralized control strategy for control. The local overvoltage suppression method based on the reactive power compensation of the PV inverter is as follows:

[0163]

[0164] Among them, is the reactive power change amount of the g-th low-voltage distributed PV at t = t j moment, is the in-situ measured voltage of the g-th low-voltage distributed PV at t = t j moment, is the local voltage control coefficient, which is generally obtained according to the preset reactive power-voltage droop control slope of the PV inverter. Every Δt, the PV inverter executes local control and updates its reactive power absorption amount. In a centralized control cycle, the algorithm flow chart is as Figure 13 shown.

[0165] From the above description, it can be seen that the multi-time scale voltage regulation method for high, medium, and low-voltage distribution networks provided by this application can utilize the pre-constructed coordinated regulation model of high, medium, and low-voltage distribution networks to regulate the reactive power of the medium-voltage distributed PV, so as to regulate the voltage of high, medium, and low-voltage distribution networks.

[0166] Based on the same inventive concept, the embodiment of this application also provides a multi-time scale voltage regulation device for high, medium, and low-voltage distribution networks, which can be used to implement the method described in the above embodiment, as described in the following embodiment. Since the principle of solving problems by the multi-time scale voltage regulation device for high, medium, and low-voltage distribution networks is similar to that of the multi-time scale voltage regulation method for high, medium, and low-voltage distribution networks, the implementation of the multi-time scale voltage regulation device for high, medium, and low-voltage distribution networks can refer to the implementation of the method for determining the software performance benchmark, and the repeated parts will not be described again. Hereinafter, the term "unit" or "module" can be a combination of software and / or hardware that can achieve a predetermined function. Although the systems described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0167] In one embodiment, refer to Figure 6, in order to comprehensively consider the tap of the slow - motion on - load tap - changing transformer, the medium - voltage distributed photovoltaic power station with good communication conditions, and the low - voltage distributed photovoltaic with weak communication conditions, construct a coordinated control model for high - medium - low voltage distribution networks, and perform voltage regulation on high - medium - low voltage distribution networks at multiple time scales, the present application provides a multi - time - scale voltage regulation device for high - medium - low voltage distribution networks, including: a power - load ratio determination unit 601, a voltage estimated value generation unit 602, a voltage predicted value generation unit 603, and a coordinated centralized voltage regulation unit 604.

[0168] The power - load ratio determination unit 601 is used to determine the ratio of the active power of the distributed photovoltaic cluster to the load according to the short - term load prediction value of the distribution network for the next day and the predicted active power value of the distributed photovoltaic cluster in the distribution network; wherein, the distributed photovoltaic cluster includes medium - voltage distributed photovoltaic and low - voltage distributed photovoltaic;

[0169] The voltage estimated value generation unit 602 is used to determine the voltage estimated value of the preset node according to the resistance value and reactance value from the low - voltage side of the substation in the distribution network to the preset node, the rated voltage of the medium - voltage feeder, the net active power and net reactive power from the low - voltage side of the substation to the preset node.

[0170] The voltage predicted value generation unit 603 is used to, if the ratio exceeds the ratio threshold and the voltage estimated value exceeds the upper limit of the node voltage allowed by the distribution network, evaluate the reactive power adequacy of the medium - voltage feeder according to the upper limit of the node voltage of the preset node and the maximum adjustable value of the reactive power of the medium - voltage distributed photovoltaic under over - voltage conditions, and obtain the voltage predicted value of the preset node after using the photovoltaic inverter to reduce the grid - connection point voltage.

[0171] The coordinated centralized voltage regulation unit 604 is used to, if the voltage predicted value still exceeds the upper limit of the node voltage allowed by the distribution network, adjust the reactive power of the medium - voltage distributed photovoltaic by using the pre - constructed coordinated control model for high - medium - low voltage distribution networks, so as to perform voltage regulation on high - medium - low voltage distribution networks.

[0172] In one embodiment, referring to Figure 7 , the power - load ratio determination unit 601 includes: a power prediction value determination module 701, a load prediction value determination module 702, and a power - load ratio determination module 703.

[0173] The power prediction value determination module 701 is used to calculate the predicted active power value of the distributed photovoltaic cluster according to the number of medium - voltage distributed photovoltaics, the number of low - voltage distributed photovoltaics, the predicted active power values of each medium - voltage distributed photovoltaic, and the predicted active power values of each low - voltage distributed photovoltaic.

[0174] The load prediction value determination module 702 is configured to calculate the day-ahead short-term load prediction value according to the quantity of the loads and the predicted active power values of the loads.

[0175] The power-load ratio determination module 703 is configured to determine the ratio of the predicted active power of the distributed photovoltaic cluster to the day-ahead short-term load prediction value as the ratio of the active power to the load.

[0176] In one embodiment, referring to Figure 8 , the voltage estimation value generation unit 602 includes: a first subtraction number determination module 801, a second subtraction number determination module 802, and a voltage estimation value generation module 803.

[0177] The first subtraction number determination module 801 is configured to calculate a first subtraction number according to the voltage value of the high-voltage side of the substation in the distribution network and the transformer ratio of the substation transformer.

[0178] The second subtraction number determination module 802 is configured to calculate a second subtraction number according to the resistance value and reactance value, the net active power and net reactive power, and the rated voltage of the medium-voltage feeder.

[0179] The voltage estimation value generation module 803 is configured to determine the difference between the first subtraction number and the first subtraction number as the voltage estimation value.

[0180] In one embodiment, referring to Figure 9 , the voltage prediction value generation unit 603 includes: a maximum adjustable value determination module 901, a third subtraction number determination module 902, and a voltage prediction value generation module 903.

[0181] The maximum adjustable value determination module 901 is configured to determine the maximum adjustable value of the reactive power according to the rated capacity and rated power of the medium-voltage distributed photovoltaic.

[0182] The third subtraction number determination module 902 is configured to calculate a third subtraction number according to the maximum adjustable value of the reactive power and the change amount of the preset node voltage caused by the change amount of the unit reactive power of the medium-voltage distributed photovoltaic.

[0183] The voltage prediction value generation module 903 is configured to determine the difference between the upper limit of the node voltage of the preset node and the third subtraction number as the voltage prediction value.

[0184] In one embodiment, referring to Figure 10 , the collaborative centralized voltage regulation unit 604 includes: an objective function establishment module 1001, a transformation constraint construction module 1002, a photovoltaic constraint construction module 1003, a balance constraint construction module 1004, a voltage constraint construction module 1005, a flow constraint construction module 1006, and a first centralized voltage regulation module 1007.

[0185] The objective function establishment module 1001 is used to construct the objective function of the coordinated regulation model of the high, medium, and low voltage distribution networks according to the number of medium voltage nodes in the distribution network, the current amplitude between nodes, and the line impedance;

[0186] The transformer voltage regulation constraint construction module 1002 is used to construct the on-load tap-changer transformer constraint according to the voltage value of the low voltage side of the substation, the transformer turns ratio of the substation, the change amount of the transformer tap position of the substation, and the regulation step of the on-load tap-changer;

[0187] The PV constraint construction module 1003 is used to construct the medium voltage distributed PV power station constraint according to the apparent power prediction value, active power prediction value, reactive power prediction value, and minimum power factor of the medium voltage distributed PV;

[0188] The power balance constraint construction module 1004 is used to construct the power balance constraint according to the set of all branch head nodes with a set node as the end node, the set of all branch end nodes with the set node as the head node, the net active power injection amount and net reactive power injection amount of the set node, the node voltage of the set node, the active power prediction value of the medium voltage distributed PV, and the active power prediction value of the low voltage distributed PV;

[0189] The voltage constraint construction module 1005 is used to construct the node voltage constraint according to the lower limit of the node voltage allowed by the distribution network and the upper limit of the node voltage allowed by the distribution network;

[0190] The flow constraint construction module 1006 is used to construct the line current-carrying capacity constraint according to the maximum current-carrying capacity of the line between nodes;

[0191] The first centralized voltage regulation module 1007 is used to solve the optimal solution of the objective function under the on-load tap-changer transformer constraint, the medium voltage distributed PV power station constraint, the power balance constraint, the node voltage constraint, and the line current-carrying capacity constraint, and obtain the reactive power regulation amount of the medium voltage distributed PV.

[0192] In one embodiment, the high, medium, and low voltage distribution network multi-time scale voltage regulation device further includes:

[0193] The coordinated decentralized voltage regulation unit is used to determine the reactive power change amount of the low voltage distributed PV according to the measured voltage value of the low voltage distributed PV, the local voltage control coefficient, and the upper limit of the node voltage allowed by the distribution network, so as to regulate the voltage of the high, medium, and low voltage distribution networks.

[0194] From a hardware perspective, in order to comprehensively consider the tap of a slow-motion on-load tap-changer transformer, medium-voltage distributed photovoltaic power stations with good communication conditions, and low-voltage distributed photovoltaics with poor communication conditions, a coordinated control model for high, medium, and low-voltage distribution networks is constructed to perform voltage regulation on high, medium, and low-voltage distribution networks at multiple time scales. This application provides an embodiment of an electronic device for implementing all or part of the multi-time scale voltage regulation method for the high, medium, and low-voltage distribution networks. The electronic device specifically includes the following:

[0195] A processor, a memory, a communications interface, and a bus; wherein, the processor, the memory, and the communications interface complete communication with each other through the bus; the communications interface is used to implement information transmission between the multi-time scale voltage regulation device for the high, medium, and low-voltage distribution networks and related devices such as a core business system, a user terminal, and a related database. The logic controller can be a desktop computer, a tablet computer, a mobile terminal, etc., and this embodiment is not limited thereto. In this embodiment, the logic controller can be implemented with reference to the embodiments of the multi-time scale voltage regulation method for the high, medium, and low-voltage distribution networks and the embodiments of the multi-time scale voltage regulation device for the high, medium, and low-voltage distribution networks. The content is incorporated herein, and repeated parts will not be elaborated.

[0196] It can be understood that the user terminal may include a smart phone, a tablet electronic device, an Internet set-top box, a portable computer, a desktop computer, a personal digital assistant (PDA), a vehicle-mounted device, a smart wearable device, etc. Among them, the smart wearable device may include smart glasses, a smart watch, a smart bracelet, etc.

[0197] In practical applications, part of the multi-time scale voltage regulation method for the high, medium, and low-voltage distribution networks can be executed on the electronic device side as described above, or all operations can be completed in the client device. Specifically, it can be selected according to the processing capacity of the client device and the limitations of the user usage scenario. This application does not make any limitations in this regard. If all operations are completed in the client device, the client device may further include a processor.

[0198] The above-mentioned client device may have a communication module (i.e., a communication unit), and can be communicatively connected to a remote server to achieve data transmission with the server. The server may include a server on the task scheduling center side, and in other implementation scenarios, it may also include a server of an intermediate platform, such as a server of a third-party server platform communicatively linked to the task scheduling center server. The server may include a single computer device, or may include a server cluster composed of multiple servers, or a server structure of a distributed device.

[0199] Figure 11 It is a schematic block diagram of the system composition of the electronic device 9600 according to an embodiment of the present application. As Figure 11 shown, the electronic device 9600 may include a central processing unit 9100 and a memory 9140; the memory 9140 is coupled to the central processing unit 9100. It should be noted that this Figure 11 is exemplary; other types of structures may also be used to supplement or replace this structure to achieve telecommunication functions or other functions.

[0200] In one embodiment, the multi-time scale voltage regulation method function of the high, medium and low voltage distribution network can be integrated into the central processing unit 9100. Among them, the central processing unit 9100 can be configured to perform the following controls:

[0201] S101: Determine the ratio of the active power of the distributed photovoltaic cluster to the load according to the day-ahead short-term load prediction value of the distribution network and the predicted active power value of the distributed photovoltaic cluster in the distribution network; wherein, the distributed photovoltaic cluster includes medium-voltage distributed photovoltaics and low-voltage distributed photovoltaics;

[0202] S102: Determine the voltage estimation value of the preset node according to the resistance value and reactance value from the low-voltage side of the substation in the distribution network to the preset node, the rated voltage of the medium-voltage feeder, the net active power and net reactive power from the low-voltage side of the substation to the preset node;

[0203] S103: If the ratio exceeds the ratio threshold and the voltage estimation value exceeds the upper limit of the node voltage allowed by the distribution network, evaluate the reactive power adequacy of the medium-voltage feeder according to the upper limit of the node voltage of the preset node and the maximum adjustable reactive power value of the medium-voltage distributed photovoltaic under overvoltage conditions, and obtain the voltage prediction value of the preset node after using the photovoltaic inverter to reduce the grid connection point voltage;

[0204] S104: If the voltage prediction value still exceeds the upper limit of the node voltage allowed by the distribution network, use the pre-constructed high, medium and low voltage distribution network coordinated control model to adjust the reactive power of the medium-voltage distributed photovoltaic to regulate the voltage of the high, medium and low voltage distribution network.

[0205] As can be seen from the above description, the multi-time scale voltage regulation method and device for high, medium, and low voltage distribution networks provided by this application can consider the differences in measurement and communication configurations of different voltage levels in the distribution network, incorporate adjustable resources with different action time scales into different optimization time scales, and construct a coordinated control model for high, medium, and low voltage distribution networks, also known as a multi-time scale voltage regulation model for high, medium, and low voltage distribution networks. For high and medium voltage distribution networks with "remote measurement", "remote signaling", and "remote regulation" functions, a centralized control method is adopted to regulate adjustable resources by establishing a centralized optimization model. For low voltage distribution networks with only weak measurement capabilities, a decentralized local control method for low voltage distributed photovoltaics is adopted for regulation. Considering the decisive influence of substation voltage on the power flow distribution of medium and low voltage distribution networks, the tap positions of on-load tap changers in substations are incorporated into the coordinated control model of high, medium, and low voltage distribution networks, fully considering the physical constraints of the tap action times and action times of transformers, and reducing the number of calculations in the centralized control stage of the regulation process through two judgments.

[0206] In another embodiment, the multi-time scale voltage regulation device for high, medium, and low voltage distribution networks can be separately configured from the central processor 9100. For example, the multi-time scale voltage regulation device of the data composite transmission device can be configured as a chip connected to the central processor 9100, and the functions of the multi-time scale voltage regulation method for high, medium, and low voltage distribution networks can be realized through the control of the central processor.

[0207] As Figure 11 shown, the electronic device 9600 may further include: a communication module 9110, an input unit 9120, an audio processor 9130, a display 9160, and a power supply 9170. It should be noted that the electronic device 9600 does not necessarily have to include Figure 11 all the components shown in Figure 11 ; in addition, the electronic device 9600 may further include

[0208] components not shown in Figure 11 ; reference may be made to the prior art.

[0209] Among them, the memory 9140 can be, for example, one or more of a buffer, a flash memory, a hard drive, a removable medium, a volatile memory, a non-volatile memory, or other suitable devices. The above information related to failures can be stored, and in addition, programs for executing relevant information can also be stored. And the central processor 9100 can execute the program stored in the memory 9140 to implement information storage or processing, etc.

[0210] The input unit 9120 provides input to the central processing unit 9100. The input unit 9120 is, for example, a key or a touch input device. The power supply 9170 is used to supply power to the electronic device 9600. The display 9160 is used to display display objects such as images and texts. The display may be, for example, an LCD display, but is not limited thereto.

[0211] The memory 9140 may be a solid-state memory, for example, a read-only memory (ROM), a random access memory (RAM), a SIM card, etc. It may also be such a memory that stores information even when power is off, can be selectively erased and has more data. Examples of this memory are sometimes referred to as EPROMs, etc. The memory 9140 may also be some other type of device. The memory 9140 includes a buffer memory 9141 (sometimes referred to as a buffer). The memory 9140 may include an application / function storage section 9142 that is used to store application programs and function programs or the processes for operating the electronic device 9600 through the central processing unit 9100.

[0212] The memory 9140 may also include a data storage section 9143 that is used to store data, such as contacts, digital data, pictures, sounds, and / or any other data used by the electronic device. The driver storage section 9144 of the memory 9140 may include various drivers of the electronic device for communication functions and / or for performing other functions of the electronic device (such as a messaging application, an address book application, etc.).

[0213] The communication module 9110 is a transmitter / receiver that transmits and receives signals via the antenna 9111. The communication module (transmitter / receiver) 9110 is coupled to the central processing unit 9100 to provide input signals and receive output signals, which may be the same as in the case of a conventional mobile communication terminal.

[0214] Based on different communication technologies, multiple communication modules 9110 may be provided in the same electronic device, such as a cellular network module, a Bluetooth module, and / or a wireless local area network module, etc. The communication module (transmitter / receiver) 9110 is also coupled to the speaker 9131 and the microphone 9132 via the audio processor 9130 to provide an audio output via the speaker 9131 and receive an audio input from the microphone 9132, thereby implementing the usual telecommunications functions. The audio processor 9130 may include any suitable buffer, decoder, amplifier, etc. Additionally, the audio processor 9130 is also coupled to the central processing unit 9100, so that recording can be performed on the local machine through the microphone 9132, and the sound stored on the local machine can be played through the speaker 9131.

[0215] Embodiments of the present application also provide a computer-readable storage medium capable of implementing all steps of the multi-time scale voltage regulation method for high, medium, and low voltage distribution networks with the execution entity being a server or a client in the above embodiments. A computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, all steps of the multi-time scale voltage regulation method for high, medium, and low voltage distribution networks with the execution entity being a server or a client in the above embodiments are implemented. For example, when the processor executes the computer program, the following steps are implemented:

[0216] S101: Determine the ratio of the active power of the distributed photovoltaic cluster to the load according to the day-ahead short-term load forecast value of the distribution network and the predicted active power value of the distributed photovoltaic cluster in the distribution network; wherein, the distributed photovoltaic cluster includes medium-voltage distributed photovoltaics and low-voltage distributed photovoltaics;

[0217] S102: Determine the voltage estimate value of the preset node according to the resistance value and reactance value from the low-voltage side of the substation in the distribution network to the preset node, the rated voltage of the medium-voltage feeder, the net active power and net reactive power from the low-voltage side of the substation to the preset node;

[0218] S103: If the ratio exceeds the ratio threshold and the voltage estimate value exceeds the upper limit of the node voltage allowed by the distribution network, evaluate the reactive power adequacy of the medium-voltage feeder according to the upper limit of the node voltage of the preset node and the maximum adjustable reactive power value of the medium-voltage distributed photovoltaics under overvoltage conditions, and obtain the voltage prediction value of the preset node after using the photovoltaic inverter to reduce the grid connection point voltage;

[0219] S104: If the voltage prediction value still exceeds the upper limit of the node voltage allowed by the distribution network, use the pre-constructed coordinated regulation model of high, medium, and low voltage distribution networks to adjust the reactive power of the medium-voltage distributed photovoltaics to regulate the voltage of the high, medium, and low voltage distribution networks.

[0220] As can be seen from the above description, the multi-time scale voltage regulation method and device for high, medium and low voltage distribution networks provided by this application can consider the differences in measurement and communication configurations of different voltage levels in the distribution network, incorporate adjustable resources with different action time scales into different optimization time scales, and construct a coordinated control model for high, medium and low voltage distribution networks, also known as the multi-time scale voltage regulation model for high, medium and low voltage distribution networks; for high and medium voltage distribution networks with the functions of "remote measurement", "remote signaling" and "remote regulation", a centralized control method is adopted to regulate adjustable resources by establishing a centralized optimization model. For low voltage distribution networks with only weak measurement capabilities, a decentralized local control method for low voltage distributed photovoltaics is adopted for regulation; considering the decisive influence of substation voltage on the power flow distribution of medium and low voltage distribution networks, the tap positions of on-load tap-changers in substations are incorporated into the coordinated control model for high, medium and low voltage distribution networks, fully considering the physical constraints of the tap action times and action times of transformers, and reducing the number of calculations in the centralized control stage of the regulation process through two judgments.

[0221] Those skilled in the art should understand that the embodiments of the present invention can be provided as methods, devices, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0222] The present invention is described with reference to the flowcharts and / or block diagrams of methods, devices, and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, and the combination of processes and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for realizing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0223] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device realizes the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0224] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions for implementing the steps of the process Figure 1 one process or a plurality of processes and / or blocks Figure 1 steps of the functions specified in one block or a plurality of blocks.

[0225] In the present invention, specific embodiments are used to illustrate the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. At the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A multi-time-scale voltage regulation method for high, medium and low voltage distribution networks, characterized in that, Including: Determining a ratio of the active power of the distributed photovoltaic cluster to the load according to the day-ahead short-term load prediction value of the distribution network and the predicted active power value of the distributed photovoltaic cluster in the distribution network; wherein, the distributed photovoltaic cluster includes medium-voltage distributed photovoltaics and low-voltage distributed photovoltaics; Determining an estimated voltage value of the preset node according to the resistance value and reactance value from the low-voltage side of the substation in the distribution network to the preset node, the rated voltage of the medium-voltage feeder, the net active power and net reactive power from the low-voltage side of the substation to the preset node; If the ratio exceeds a ratio threshold and the estimated voltage value exceeds the upper limit value of the node voltage allowed by the distribution network, obtaining a predicted voltage value of the preset node after using the photovoltaic inverter to reduce the grid connection point voltage according to the upper limit value of the node voltage of the preset node and the maximum adjustable reactive power value of the medium-voltage distributed photovoltaic under overvoltage conditions; If the predicted voltage value exceeds the upper limit value of the node voltage allowed by the distribution network, using a pre-constructed coordinated regulation model of high, medium, and low voltage distribution networks to adjust the reactive power of the medium-voltage distributed photovoltaic to regulate the voltage of the high, medium, and low voltage distribution networks.

2. The multi-time-scale voltage regulation method for high, medium, and low voltage distribution networks according to claim 1, wherein The determining the ratio of the active power of the distributed photovoltaic cluster to the load according to the day-ahead short-term load prediction value of the distribution network and the predicted active power value of the distributed photovoltaic cluster in the distribution network includes: Calculating the predicted active power value of the distributed photovoltaic cluster according to the number of medium-voltage distributed photovoltaics, the number of low-voltage distributed photovoltaics, the predicted active power values of each medium-voltage distributed photovoltaic, and the predicted active power values of each low-voltage distributed photovoltaic; Calculating the day-ahead short-term load prediction value according to the number of the loads and the predicted active power values of each load; Determining the ratio of the predicted active power value of the distributed photovoltaic cluster to the day-ahead short-term load prediction value as the ratio of the active power to the load.

3. The multi-time-scale voltage regulation method for high, medium, and low voltage distribution networks according to claim 2, wherein The determining the estimated voltage value of the preset node according to the resistance value and reactance value from the low-voltage side of the substation in the distribution network to the preset node, the rated voltage of the medium-voltage feeder, the net active power and net reactive power from the low-voltage side of the substation to the preset node includes: Calculating a first subtraction number according to the voltage value of the high-voltage side of the substation in the distribution network and the transformer turns ratio of the substation; Calculating a second subtraction number according to the resistance value and reactance value, the net active power and net reactive power, and the rated voltage of the medium-voltage feeder; Determining the difference between the first subtraction number and the first subtraction number as the estimated voltage value.

4. The multi-time-scale voltage regulation method for high, medium and low voltage distribution networks according to claim 1, characterized in that The obtaining the predicted voltage value of the preset node after using the photovoltaic inverter to reduce the grid connection point voltage according to the upper limit value of the node voltage of the preset node and the maximum adjustable reactive power value of the medium-voltage distributed photovoltaic under overvoltage conditions includes: Determining the maximum adjustable reactive power value according to the rated capacity and rated power of the medium-voltage distributed photovoltaic; Calculating a third subtraction number according to the maximum adjustable reactive power value and the change amount of the preset node voltage caused by the change amount of the unit reactive power of the medium-voltage distributed photovoltaic; Determining the difference between the upper limit value of the node voltage of the preset node and the third subtraction number as the predicted voltage value.

5. The multi-time scale voltage regulation method for high, medium and low voltage distribution networks according to claim 3, wherein If the predicted voltage value exceeds the upper limit of the node voltage allowed by the distribution network, regulating the reactive power of the medium-voltage distributed photovoltaic by using the pre-constructed coordinated regulation model of the high, medium, and low-voltage distribution networks, including: Constructing an objective function of the coordinated regulation model of the high, medium, and low-voltage distribution networks according to the number of medium-voltage nodes in the distribution network, the current amplitude between nodes, and the line impedance; Constructing a constraint of the on-load tap-changer transformer according to the voltage value of the low-voltage side of the substation, the transformation ratio of the substation transformer, the change amount of the substation transformer tap position, and the adjustment step of the on-load tap-changer; Constructing a constraint of the medium-voltage distributed photovoltaic power station according to the predicted apparent power value, the predicted active power value, the predicted reactive power value, and the minimum power factor of the medium-voltage distributed photovoltaic; Constructing a power balance constraint according to the set of all branch head nodes with a set node as the end node, the set of all branch end nodes with the set node as the head node, the net injection of active power and reactive power of the set node, the node voltage of the set node, the predicted active power value of the medium-voltage distributed photovoltaic, and the predicted active power value of the low-voltage distributed photovoltaic; Constructing a node voltage constraint according to the lower limit of the node voltage allowed by the distribution network and the upper limit of the node voltage allowed by the distribution network; Constructing a line current-carrying capacity constraint according to the maximum current-carrying capacity between nodes; Solving the optimal solution of the objective function under the constraints of the on-load tap-changer transformer, the medium-voltage distributed photovoltaic power station, the power balance, the node voltage, and the line current-carrying capacity constraints to obtain the reactive power adjustment amount of the medium-voltage distributed photovoltaic; 6. The multi-time-scale voltage regulation method for high, medium and low voltage distribution networks according to claim 1, characterized in that After regulating the reactive power of the medium-voltage distributed photovoltaic by using the pre-constructed coordinated regulation model of the high, medium, and low-voltage distribution networks, it further includes: Determining the change amount of the reactive power of the low-voltage distributed photovoltaic according to the measured voltage value of the low-voltage distributed photovoltaic, the local voltage control coefficient, and the upper limit of the node voltage allowed by the distribution network to regulate the voltage of the high, medium, and low-voltage distribution networks.

7. A multi-time-scale voltage regulating device for high, medium and low voltage distribution networks, characterized in that, Including: A power load ratio determination unit for determining the ratio of the active power of the distributed photovoltaic cluster to the load according to the day-ahead short-term load prediction value of the distribution network and the predicted active power value of the distributed photovoltaic cluster in the distribution network; wherein, the distributed photovoltaic cluster includes medium-voltage distributed photovoltaic and low-voltage distributed photovoltaic; A voltage estimated value generation unit for determining the voltage estimated value of the preset node according to the resistance value and reactance value from the low-voltage side of the substation in the distribution network to the preset node, the rated voltage of the medium-voltage feeder, the net active power and net reactive power from the low-voltage side of the substation to the preset node; A voltage predicted value generation unit for, if the ratio exceeds the ratio threshold and the voltage estimated value exceeds the upper limit of the node voltage allowed by the distribution network, obtaining the voltage predicted value of the preset node after reducing the grid connection point voltage by using the photovoltaic inverter according to the upper limit of the node voltage of the preset node and the maximum adjustable value of the reactive power of the medium-voltage distributed photovoltaic under overvoltage conditions; A collaborative centralized voltage regulation unit, which is used to, if the voltage prediction value exceeds the upper limit of the node voltage allowed by the distribution network, adjust the reactive power of the medium-voltage distributed photovoltaic by using a pre-constructed collaborative regulation model of high, medium and low voltage distribution networks, so as to regulate the voltage of the high, medium and low voltage distribution networks.

8. The multi-time-scale voltage regulating device for high, medium and low voltage distribution networks according to claim 7, characterized in that, The power-load ratio determination unit includes: A power prediction value determination module, which is used to calculate the active power prediction value of the distributed photovoltaic cluster according to the number of medium-voltage distributed photovoltaics, the number of low-voltage distributed photovoltaics, the active power prediction values of each medium-voltage distributed photovoltaic and the active power prediction values of each low-voltage distributed photovoltaic; A load prediction value determination module, which is used to calculate the day-ahead short-term load prediction value according to the number of loads and the active power prediction values of each load; A power-load ratio determination module, which is used to determine the ratio of the active power to the load by taking the ratio of the active power prediction value of the distributed photovoltaic cluster to the day-ahead short-term load prediction value.

9. The multi-time scale voltage regulating device for high, medium and low voltage distribution networks according to claim 8, wherein The voltage estimation value generation unit includes: A first subtraction number determination module, which is used to calculate the first subtraction number according to the voltage value of the high-voltage side of the substation in the distribution network and the transformer ratio of the substation transformer; A second subtraction number determination module, which is used to calculate the second subtraction number according to the resistance value and reactance value, the net active power and net reactive power, and the rated voltage of the medium-voltage feeder; A voltage estimation value generation module, which is used to determine the difference between the first subtraction number and the first subtraction number as the voltage estimation value.

10. The multi-time-scale voltage regulating device for high, medium and low voltage distribution networks according to claim 7, wherein, The voltage prediction value generation unit includes: A maximum adjustable value determination module, which is used to determine the maximum adjustable value of the reactive power according to the rated capacity and rated power of the medium-voltage distributed photovoltaic; A third subtraction number determination module, which is used to calculate the third subtraction number according to the maximum adjustable value of the reactive power and the change amount of the preset node voltage caused by the change amount of the unit reactive power of the medium-voltage distributed photovoltaic; A voltage prediction value generation module, which is used to determine the difference between the upper limit value of the node voltage of the preset node and the third subtraction number as the voltage prediction value.

11. The multi-time scale voltage regulating device for high, medium and low voltage distribution networks according to claim 9, characterized in that, The collaborative centralized voltage regulation unit includes: An objective function establishment module, which is used to construct the objective function of the collaborative regulation model of high, medium and low voltage distribution networks according to the number of medium-voltage nodes in the distribution network, the current amplitude between nodes and the line impedance; A transformer voltage regulation constraint construction module, which is used to construct the on-load tap-changer transformer constraint according to the voltage value of the low-voltage side of the substation, the transformer ratio of the substation transformer, the change amount of the transformer tap position and the adjustment step of the on-load tap-changer; A photovoltaic constraint construction module, which is used to construct the medium-voltage distributed photovoltaic power station constraint according to the apparent power prediction value, active power prediction value, reactive power prediction value and minimum power factor of the medium-voltage distributed photovoltaic; A balance constraint construction module, which is used to construct the power balance constraint according to the set of all branch head nodes with the set node as the end node, the set of all branch end nodes with the set node as the head node, the net injection amount of active power and reactive power of the set node, the node voltage of the set node, the active power prediction value of the medium-voltage distributed photovoltaic and the active power prediction value of the low-voltage distributed photovoltaic; A voltage constraint construction module, configured to construct node voltage constraints according to the lower limit of the node voltage allowed by the distribution network and the upper limit value of the node voltage allowed by the distribution network; A flow constraint construction module, configured to construct line current-carrying capacity constraints according to the maximum current-carrying capacity of the lines between nodes; A first centralized voltage regulation module, configured to solve the optimal solution of the objective function under the on-load tap-changer constraint, the medium-voltage distributed photovoltaic power station constraint, the power balance constraint, the node voltage constraint, and the line current-carrying capacity constraint, so as to obtain the reactive power regulation amount of the medium-voltage distributed photovoltaic; 12. The multi-time-scale voltage regulating device for high, medium and low voltage distribution networks according to claim 7, wherein It further includes: A collaborative decentralized voltage regulation unit, configured to determine the reactive power change amount of the low-voltage distributed photovoltaic according to the measured voltage value of the low-voltage distributed photovoltaic, the in-situ voltage control coefficient, and the upper limit value of the node voltage allowed by the distribution network, so as to regulate the voltage of the high, medium, and low voltage distribution networks; 13. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, the steps of the multi-time scale voltage regulation method for the high, medium, and low voltage distribution networks according to any one of claims 1 to 6 are implemented; 14. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, the steps of the multi-time scale voltage regulation method for the high, medium, and low voltage distribution networks according to any one of claims 1 to 6 are implemented; 15. A computer program product, comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, the steps of the multi-time scale voltage regulation method for the high, medium, and low voltage distribution networks according to any one of claims 1 to 6 are implemented;

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