Distributed photovoltaic scheduling method and system considering security assessment

Abstract

A distributed photovoltaic scheduling method and system considering security assessment. The method comprises: acquiring a limit value of a power transmission and transformation device, a load condition, and distributed aggregation information under the device, calculating a device load rate, and on the basis of the device load rate in combination with a threshold value, calculating a total maximum adjustment amount of distributed photovoltaics under the device or a total over-limit correction amount of the distributed photovoltaics under the device, and then decomposing the total maximum adjustment amount or the total over-limit correction amount to obtain a total maximum adjustment amount of load points or a total over-limit correction amount of the load points; and decomposing to obtain a maximum adjustment amount or an over-limit correction amount of each automatic generation control unit, correcting adjustment requirements of each automatic generation control unit to generate a control target of each automatic generation control unit, and issuing the control target to each automatic generation control unit for execution.

Description

Distributed photovoltaic scheduling method and system considering safety check

[0001] The present application claims priority to the Chinese patent application No. 202410873868.6, filed on July 2, 2024, with the Chinese Patent Office, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of distributed photovoltaic technology, for example, to a distributed photovoltaic scheduling method and system considering safety check. BACKGROUND

[0003] The statements in this section merely provide background information related to the present application and do not necessarily constitute the prior art.

[0004] Distributed photovoltaic continues to be connected to the grid at a high speed, and the influence on the operation of the power grid presents a trend of local to global development and distribution network to main network extension.

[0005] When the high proportion of distributed photovoltaic in the area is seriously overloaded in the reverse direction, the photovoltaic tidal flow may be further sent in the reverse direction to the upper line, and in severe cases, the 220kV transformer substation and the line may be seriously overloaded in the reverse direction, affecting the flexibility of the power grid operation mode adjustment.

[0006] At the same time, new energy grows explosively, and regions with good new energy endowments often have various resources gathered, combined with the large-scale centralized access of distributed photovoltaic in the region, and in the case of wind and light, distributed photovoltaic may squeeze the wind power and centralized photovoltaic transmission channel, which poses a risk to the safety of the power grid. SUMMARY

[0007] In order to solve the above problems, the present application provides a distributed photovoltaic scheduling method and system considering safety check, which realizes accurate regulation and control through distributed photovoltaic regulation and control safety check, and can take into account power balance, tidal flow overrun and other scene regulation and control requirements.

[0008] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0009] The first aspect of the present application provides a distributed photovoltaic scheduling method considering safety check, which comprises:

[0010] Obtaining the limit value of the power transmission and transformation equipment, the load condition and the distributed aggregation information under the equipment, calculating the equipment load rate, and based on the equipment load rate, combining the threshold value, calculating the total maximum adjustment amount of the distributed photovoltaic under the equipment or the total overrun correction amount of the distributed photovoltaic under the equipment, and then decomposing the total maximum adjustment amount or the total overrun correction amount to obtain the total maximum adjustment amount of each load point or the total overrun correction amount of each load point.

[0011] Based on the total maximum adjustment amount or the total over-limit correction amount of the load points, the maximum adjustment amount or the over-limit correction amount of each automatic power generation control unit is obtained by decomposition, the adjustment demand of each automatic power generation control unit is corrected, the control target of each automatic power generation control unit is generated, and the following is executed to each automatic power generation control unit.

[0012] Further, the load points are determined as 10kV load points according to the modeling boundary of the regional dispatching system, and the automatic power generation control unit is a 10kV and above distributed station or a low-voltage distributed 10kV aggregation unit.

[0013] The step of obtaining the distributed aggregation information under the device includes: aggregating the low-voltage distributed data to the main grid load point according to the model membership relationship to obtain the low-voltage distributed aggregation information of the main grid load point, and then aggregating the low-voltage distributed aggregation information of the main grid load point to each device of the main grid through topology analysis to obtain the distributed aggregation information under each device.

[0014] Further, the total maximum adjustment amount of the distributed photovoltaic under the device includes a maximum total downward adjustment amount of the distributed photovoltaic under the device.

[0015] When the positive load rate of the device is lower than the set threshold value K1, the maximum total downward adjustment amount of the distributed photovoltaic under the device is

[0016] When the positive load rate of the device is higher than the set threshold value K1, the maximum total downward adjustment amount of the distributed photovoltaic under the device is

[0017] In the formula, is the maximum total downward adjustment amount of the distributed photovoltaic under the device d, is the positive load rate of the device d, S e,d is the operating limit value of the device d.

[0018] Further, the total maximum adjustment amount of the distributed photovoltaic under the device includes a maximum total consumption amount of the distributed photovoltaic under the device.

[0019] When the reverse load rate of the device is greater than 0 and lower than the set threshold value K2, the maximum total consumption amount of the distributed photovoltaic under the device is

[0020] When the reverse load rate of the device is greater than the set threshold value K2, the maximum total consumption amount of the distributed photovoltaic under the device is

[0021] In the formula, is the maximum total consumption amount of the distributed photovoltaic under the device d, is the reverse load rate of the device d, S e,d is the operating limit value of the device d.

[0022] Further, the device under distribution photovoltaic total over-limit correction quantity In the formula, ΔP crr,d is the device d over-limit correction quantity; δ is the reserved safety margin; is the device d reverse load rate, S e,d is the device d set operation limit value.

[0023] Further, the decomposition of the total maximum adjustment quantity or the total over-limit correction quantity is carried out according to the negative sensitivity of the device to the active power injection of the load point, and the safety constraint conditions of each voltage level device are checked and corrected in turn according to the priority from the low voltage level to the high voltage level, so as to obtain the total maximum adjustment quantity of each load point or the total over-limit correction quantity of each load point.

[0024] Further, the decomposition of the total maximum adjustment quantity of the load point is carried out in different ways according to the distribution strategy in the distributed automatic power generation control group.

[0025] If the priority distribution strategy is selected for the distribution strategy in the distributed automatic power generation control group, in each round, the total adjustment demand of the automatic power generation control unit hung under the load point is calculated based on the initial adjustment demand of each automatic power generation control unit, and it is checked whether the total adjustment demand exceeds the total maximum adjustment quantity of the load point. When the initial adjustment demand is distributed to a certain automatic power generation control unit, the total adjustment demand of the load point connected to the automatic power generation control unit exceeds the total maximum adjustment quantity, the automatic power generation control unit is skipped, and the adjustment demand is not distributed; until the total adjustment demand of the automatic power generation control unit hung under the load point is completely distributed.

[0026] If the proportional distribution strategy according to the installed capacity is selected for the distribution strategy in the distributed automatic power generation control group, the total maximum adjustment quantity of the load point is proportionally distributed to the automatic power generation control unit hung under the load point according to the installed capacity.

[0027] In each instruction cycle, the initial adjustment demand of each automatic power generation control unit is corrected according to the adjustment step, capacity constraint and maximum adjustment quantity of the automatic power generation control unit.

[0028] Further, the decomposition of the total over-limit correction quantity of the load point is carried out in the same way according to the group distribution strategy selected by the distributed automatic power generation control, and is decomposed to the automatic power generation control unit hung under the load point as the down-regulation quantity of the automatic power generation control unit.

[0029] Further, when the total adjustment demand of the automatic power generation control area and the over-limit correction quantity are in the same direction, the absolute value of the adjustment demand of each automatic power generation control unit is taken as the maximum value between the absolute value of the initial adjustment demand obtained by the decomposition according to the set strategy and the absolute value between the over-limit correction quantity of the automatic power generation control unit, and the direction of the adjustment demand of the automatic power generation control unit is down-regulation.

[0030] When the automatic generation control area total regulation demand and the out-of-limit correction amount are opposite, the automatic generation control control units under the blocked equipment all execute according to the allocated out-of-limit correction amount, at the same time, the downward adjustment amount generated due to the equipment blockage is superimposed in the opposite direction to the automatic generation control area total regulation demand, then the automatic generation control area total regulation demand is decomposed according to the inter-group distribution strategy and the intra-group distribution strategy, the control units participating in the out-of-limit correction do not participate in the decomposition and distribution of the area total regulation demand in this round, and the regulation demand of each automatic generation control unit is obtained.

[0031] The second aspect of the present application provides a distributed photovoltaic scheduling system considering safety checking, which comprises:

[0032] A scheduling safety checking module is configured to: acquire the limit value of power transmission and transformation equipment, load conditions and distributed aggregation information under the equipment, calculate the equipment load rate, and based on the equipment load rate, combined with the threshold value, calculate the total maximum adjustment amount of distributed photovoltaic under the equipment or the total out-of-limit correction amount of distributed photovoltaic under the equipment, then decompose the total maximum adjustment amount or the total out-of-limit correction amount to obtain the total maximum adjustment amount of each load point or the total out-of-limit correction amount of each load point;

[0033] A distributed automatic generation control module is configured to: based on the total maximum adjustment amount or the total out-of-limit correction amount of each load point, decompose to obtain the maximum adjustment amount or the out-of-limit correction amount of each automatic generation control unit, correct the regulation demand of each automatic generation control unit, generate the control target of each automatic generation control unit, and send it to each automatic generation control unit for execution.

[0034] Further, it further comprises a resource aggregation module configured to: aggregate low-voltage distributed data to main grid load points according to model membership relationship to obtain low-voltage distributed aggregation information of main grid load points, and then aggregate the low-voltage distributed aggregation information of main grid load points to each equipment of the main grid through topological analysis to obtain the distributed aggregation information under each equipment.

[0035] Compared with the related art, the present application has the following beneficial effects:

[0036] Based on the hierarchical collaborative control architecture, the present application gives the safety constraint condition of distributed photovoltaic regulation and control through scheduling safety checking according to the equipment load rate state, and realizes accurate regulation and control of distributed photovoltaic while taking into account power balance, power flow out-of-limit and other multi-scenario regulation and control requirements. BRIEF DESCRIPTION OF DRAWINGS

[0037] The drawings constituting a part of the specification of the present application are used to provide further understanding of the present application, the illustrative embodiments of the present application and their descriptions are used to explain the present application, and do not constitute limitation of the present application.

[0038] Figure 1 is a flow chart of a safety check considering distributed photovoltaic scheduling method according to an embodiment of the present application;

[0039] Figure 2 is a hierarchical collaborative control architecture diagram according to an embodiment of the present application. DETAILED DESCRIPTION

[0040] The present application will be further described below in conjunction with the accompanying drawings and embodiments.

[0041] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0042] In the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be further described below in conjunction with the accompanying drawings and embodiments.

[0043] Embodiment One

[0044] The purpose of this embodiment is to provide a safety check considering distributed photovoltaic scheduling method.

[0045] The safety check considering distributed photovoltaic scheduling method provided by the present embodiment relies on the distributed photovoltaic provincial (county) hierarchical collaborative control architecture as shown in Figure 2. The provincial side is deployed with SCADA (Supervisory Control And Data Acquisition, data acquisition and monitoring control system), distributed AGC (Automatic Generation Control) and thermal power AGC, and the ground side is deployed with SCADA, distributed AGC and PAS (Power Application System high-level application software), to realize scheduling and distributed information interaction of each voltage level. The distribution side is configured with a power distribution automation system. The marketing side is configured with a user information acquisition system (user information acquisition system) and a load control management system.

[0046] Based on the above hierarchical collaborative control architecture, the provincial and ground levels interact with regional distributed aggregation information, provincial and ground collaborative state information and regional distributed provincial and ground collaborative control targets.

[0047] The ground level realizes 10kV and above distributed station data acquisition and control instruction issuing through safety access area via scheduling data network or 5G wireless private network; the ground level also realizes wireless acquisition of 10kV and above distributed station data through the power distribution automation system (safety I area).

[0048] The dispatching side realizes information interaction of low-voltage distributed through the intelligent power grid dispatching and control system (D5000 system) (safety I area) of the province dispatching, the energy management system (EMS) (safety I area) of the local dispatching, the multi-element collaborative management system (dispatching and control cloud) (safety III area) of the province (local), and the power utilization information collection system and the load control management system of the marketing side.

[0049] The power utilization information collection system collects low-voltage distributed data, forwards the low-voltage distributed data to the multi-element collaborative management system of the province dispatching, and the multi-element collaborative management system of the province dispatching sends the aggregated information of the low-voltage distributed in the whole province to the D5000 system of the province dispatching, receives the total control target of the low-voltage distributed generated by the D5000 system of the province dispatching, and forwards the total control target to the load control management system of the marketing side to be issued to the low-voltage distributed users. At the same time, the multi-element collaborative management system of the province dispatching sends the low-voltage distributed data of each region to the EMS system of the local dispatching through the multi-element collaborative management system of the corresponding local dispatching, receives the regulation demand and safety constraint of the low-voltage distributed generated by the EMS system of the local dispatching, and forwards the regulation demand and safety constraint to the load control management system of the marketing side to be issued to the low-voltage distributed users for execution, so as to realize observation and regulation of the low-voltage distributed photovoltaic by the province dispatching and the local dispatching.

[0050] Due to the characteristics of the low-voltage distributed power supply, such as large number and small single capacity, if the low-voltage distributed power supply is modeled in the EMS system as a conventional generator, the modeling workload is large and cumbersome. Therefore, the multi-element collaborative management system of the local dispatching aggregates the low-voltage distributed data of the marketing side received from the multi-element collaborative management system of the province dispatching according to the model membership relationship (10kV outgoing line of substation - area - distribution transformer - low-voltage distributed photovoltaic user) to the 10kV load equipment of the dispatching side, forms the low-voltage distributed aggregated information of the 10kV load point of the main network (i.e., the aggregated information of the 10kV load point of the low-voltage distributed in the region, or the aggregated information of the distributed under the 10kV load point), and sends the low-voltage distributed aggregated information to the EMS system of the local dispatching to participate in the safety check and distributed AGC regulation control of the PAS of the local dispatching.

[0051] After the EMS system of the local dispatching obtains the low-voltage distributed aggregated information of the 10kV load point of the main network and the 10kV and above distributed photovoltaic station information forwarded by the multi-element collaborative management system, the PAS further aggregates the distributed resources based on the topology analysis, obtains the aggregated information of the distributed photovoltaic mounted under the corresponding equipment (i.e., the aggregated amount of the distributed resources under the equipment, or the distributed aggregated information under the equipment) according to the dimensions of the main transformer, bus, line, etc. The process is as follows: according to the hierarchical characteristics of the power grid of different voltage levels, the topology analysis is performed, the connection relationship of the connected lines is partitioned and topologically analyzed in the same voltage level; through the topology analysis, the distributed power supply connected to the low-voltage level is traced back to the power supply path from the 10kV load point, and the aggregated amount of the distributed resources under the devices such as the main transformer, bus, and line of each level of the analysis power grid is obtained. The aggregated model attributes include: current active power, total capacity, adjustable amount, etc.

[0052] The embodiment provides a distributed photovoltaic scheduling method considering safety checking, as shown in FIG. 1, which comprises the following steps.

[0053] Step 1: The PAS (Power Application System, advanced application software) safety checking function judges whether the equipment is overloaded / over-limit and the degree of overload / over-limit according to the positive / negative load rate of the equipment, calculates the total amount of safety constraints of the distributed photovoltaic under the equipment, and calculates the total amount of safety constraints of the distributed photovoltaic under each 10kV load point based on the sensitivity information of the active power injection of the equipment and the 10kV load point, including: the maximum total downward adjustment amount of the distributed photovoltaic of the 10kV load point, the maximum total consumption amount of the distributed photovoltaic of the 10kV load point, the total over-limit correction amount of the distributed photovoltaic of the 10kV load point, and provides the AGC.

[0054] (1) Load rate.

[0055] The thermal stability evaluation takes the principle that the thermal stability of the power grid transmission and transformation equipment such as transformers and lines does not exceed the limit, adopts equipment load rate evaluation, and the equipment load rate is calculated according to the power grid operation mode, the limit value of the power transmission and transformation equipment (the actual operation limit value of the transformer or line), the load condition (the measured load of the equipment) and the distributed aggregation information under the equipment (the output of the distributed photovoltaic power supply under the transformer or line).

[0056] The equipment load rate includes the positive load rate and the negative load rate.

[0057] The calculation formula of the negative load rate is:

[0058] In the formula, P D is the output of the distributed photovoltaic power supply under the transformer or line, S e is the actual operation limit value of the transformer or line; P L is the equivalent load of the transformer or line, that is, the load removes the output of the power supply other than the distributed power supply, and the measured load P t of the current equipment is the coupling value of the load and all power supply outputs, that is: P t = P L -P D .

[0059] Therefore, the calculation formula of the negative load rate is modified as:

[0060] Similarly, when P t > 0, the positive load rate of the equipment is:

[0061] (2) Calculate the total amount of safety constraints of the distributed photovoltaic under the equipment.

[0062] According to the positive / negative load rate of the device and the set threshold value, the running state of the device is judged, and the total amount of distributed photovoltaic safety constraints under the device (including the total maximum adjustment amount of distributed photovoltaic under the device and the total correction amount of distributed photovoltaic under the device) is calculated.

[0063] (201) When the positive load rate of the device is lower than the set threshold value K1, it is a normal state, at this time, according to the load rate of the device and the set threshold value K1, the maximum total downward adjustment amount of distributed photovoltaic under the device is calculated, and is decomposed to the 10kV load point with high sensitivity according to the set strategy.

[0064] The calculation formula of the maximum total downward adjustment amount of distributed photovoltaic under the device is: In the formula, is the maximum total downward adjustment amount of distributed photovoltaic connected under the device d, is the positive load rate of the device d, S e,d is the running limit value set for the device d.

[0065] (202) When the positive load rate of the device is higher than the set threshold value K1, it is a heavy load or over-limit state, at this time, in order to prevent the deterioration of power flow, the maximum total downward adjustment amount of distributed photovoltaic under the device is 0, that is:

[0066] At this time, the 10kV station and the low-voltage distributed 10kV aggregation unit under the 10kV load point are prohibited to be adjusted downward, and the current output is taken as the lower limit of adjustment.

[0067] (203) When the negative load rate λ - of the device is greater than 0 and lower than the set threshold value K2, it is a reverse sending state, at this time, according to the negative load rate of the device and the set threshold value K2, the maximum total consumption amount of distributed photovoltaic under the device is calculated, and is decomposed to the 10kV load point with high sensitivity according to the set strategy.

[0068] The calculation formula of the maximum total consumption amount of distributed photovoltaic under the device is: In the formula, is the maximum total consumption amount of distributed photovoltaic connected under the device d, is the negative load rate of the device d, S e,d is the running limit value set for the device d.

[0069] (204) When the negative load rate λ - of the device is higher than the set threshold value K2, it is a reverse sending heavy load state, at this time, in order to prevent the deterioration of power flow, the maximum total consumption amount of distributed photovoltaic under the device is 0, that is:

[0070] At this time, the 10kV field station and low-voltage distributed 10kV aggregation unit under the 10kV load point are prohibited from being adjusted upward, and the current output is taken as the upper limit of the adjustment.

[0071] (205) When the equipment reverse load rate λ - When it is higher than 100%, that is, when it is in the reverse sending out-of-limit state, the total out-of-limit correction amount of the distributed photovoltaic under the equipment is calculated, and the set strategy is decomposed to the 10kV load point with high sensitivity, that is, the distributed downward adjustment demand of the 10kV load point.

[0072] The equipment out-of-limit correction amount is calculated according to the set operation limit and the actual power flow, and a safety margin is introduced considering the safety buffer zone, and the total out-of-limit correction amount of the distributed photovoltaic under the equipment is calculated according to the following formula: In the formula, ΔP crr,d is the equipment d out-of-limit correction amount; δ is the reserved safety margin; is the equipment d reverse load rate, S e,d is the set operation limit of the equipment d.

[0073] (3) Calculate the total safety constraint amount of the distributed photovoltaic under the 10kV load point.

[0074] Through the sensitivity analysis of the equipment and the active power injection of the 10kV load point, the total maximum adjustment amount of the distributed photovoltaic under the equipment (including the maximum total downward adjustment amount of the distributed photovoltaic under the equipment and the maximum total consumption amount of the distributed photovoltaic under the equipment) or the total out-of-limit correction amount is decomposed to each 10kV load point, and the total maximum adjustment amount of each 10kV load point and the total out-of-limit correction amount of each 10kV load point are generated, and then sent to the distributed AGC to correct the corresponding distributed adjustment demand.

[0075] Considering that the distributed photovoltaic mainly has the influence of reverse power flow on the 10kV and above equipment of the power grid, the 10kV load point uses the negative sensitivity index for evaluation. In order to minimize the node output adjustment amount for eliminating equipment overload, the nodes with larger sensitivity are preferentially dispatched, for which, a sensitivity threshold value is set, when the negative sensitivity of the 10kV load point to the equipment exceeds the set threshold value, the safety constraint under the equipment is borne, that is, the corresponding equipment operation state, the maximum adjustment amount or the power flow correction amount is obtained by taking the prohibition of upward / downward or decomposition, and the calculation formula is as follows:

[0076] In the formula, s d,i is the negative sensitivity of the equipment d to the active power injection of the 10kV load point i, ΔP d is the active power change amount of the equipment d, and the corresponding ΔP crr,d , ΔP d,iThe distributed photovoltaic active variation at 10kV load point i, i.e., the total amount of distributed photovoltaic safety constraints corresponding to the 10kV load point i generated by the device d thermal stability constraint and sensitivity analysis, is the total maximum adjustment amount or total out-of-limit correction amount of the 10kV load point i.

[0077] Considering the influence of the access of the distributed photovoltaic, the voltage level extends from the main network to the high voltage level, and the safety check starts from the 10kV load point and checks the priority layer by layer from the low voltage level (lower layer) to the high voltage level (upper layer), and the 10kV load point safety constraint condition is obtained by correction from bottom to top. In the correction process, the maximum adjustable amount takes the minimum value of the absolute value, and the out-of-limit correction amount takes the maximum value of the absolute value, and finally the maximum adjustable amount and the out-of-limit correction amount of each 10kV load point are obtained.

[0078] Step 2: AGC determines the periodic reading of PAS safety check function calculation generated 10kV load point maximum total adjustment amount (including maximum total down-regulation amount and maximum total consumption amount), and decomposes to generate the maximum adjustment amount of each 10kV and above distributed station and low-voltage distributed 10kV aggregation unit according to the set strategy, as the constraint condition of AGC instruction issuance.

[0079] According to the in-group distribution strategy selected by the distributed AGC, the 10kV load point maximum total adjustment amount is taken as the total instruction limit value of the AGC control unit (10kV and above distributed station or low-voltage distributed 10kV aggregation unit) under the 10kV load point.

[0080] (1) When the distributed AGC adopts the priority distribution strategy.

[0081] When the distributed AGC performs initial adjustment demand distribution according to the load rate sorting (down-regulation demand is sorted from high to low according to the load rate, and up-regulation demand is sorted from low to high according to the load rate), in a certain round, the total adjustment demand of the AGC control unit (10kV and above distributed station or low-voltage distributed 10kV aggregation unit) hanging under the 10kV load point is calculated in real time, and it is checked whether it exceeds the total maximum total adjustment amount of the 10kV load point. When the distribution to a certain AGC control unit causes the total adjustment demand of the 10kV load point hanging on it to exceed the maximum total adjustment amount, the AGC control unit is skipped, and the adjustment demand is not distributed in this round; until the total adjustment demand is completely distributed.

[0082] (2) When the distributed AGC adopts the proportional distribution strategy.

[0083] When the distributed AGC performs proportional distribution according to the installed capacity, the maximum adjustment amount distribution also performs proportional distribution according to the installed capacity, i.e., the larger the installed capacity, the larger the maximum adjustment amount allocated. The calculation formula is as follows: In the formula: ΔP kThe maximum regulation amount allocated to the AGC control unit k at the 10kV load point i. N is the installed capacity of AGC control unit k; N is the total number of AGC control units at 10kV load point i, ΔP d,i This represents the total maximum regulation of distributed photovoltaic power at load point i of 10kV.

[0084] The current real-time output of the AGC control unit, superimposed with the maximum adjustment amount, yields the AGC control unit's adjustment limit considering PAS safety verification. Specifically, the current real-time output of the AGC control unit plus the maximum downward adjustment amount is the lower limit of the control unit's adjustment; when the maximum downward adjustment amount is 0, downward adjustment is prohibited, and the lower limit is the current real-time output. Similarly, the current real-time output of the AGC control unit plus the maximum absorption capacity is the upper limit of the control unit's adjustment; when the maximum absorption capacity is 0, upward adjustment is prohibited, and the upper limit is the current real-time output. The intersection of the AGC control unit's adjustment limit considering PAS safety verification and the upper and lower limits of the capacity constraints set by the AGC is taken as the actual adjustment limit of the AGC control unit.

[0085] Within each instruction cycle, the initial regulation requirement allocated to each AGC control unit (10kV and above distributed substations or low-voltage distributed 10kV aggregation units) is corrected based on its regulation step size and operating limits to obtain the regulation requirement for each control unit, namely: |ΔR′ k |=min(|ΔR k |,S k ,|ΔP k,max |). Where: ΔR′ k To adjust the control unit k AGC requirements, ΔR k To decompose and allocate the initial adjustment requirements of the control unit k AGC according to the set strategy, S k ΔP is the adjustment step size of control unit k. k,max To consider the operating limit of control unit k for power grid safety verification, capacity constraints and safety verification constraints (maximum regulation ΔP) are adopted. k The intersection of ) and only the constraints in the same direction as the adjustment demand are considered.

[0086] The control target of the control unit is obtained by superimposing the current real-time output of the control unit with the adjusted demand.

[0087] Step 3: The AGC periodically reads the 10kV load point over-limit correction amount calculated by the PAS safety verification function, decomposes it to 10kV and above distributed substations and low-voltage distributed 10kV aggregation units according to the set strategy, and corrects the AGC regulation requirements.

[0088] (1) Over-limit correction allocation logic.

[0089] 10kV load point total over-limit correction amount is only decomposed and distributed among the AGC control units associated with the 10kV load point. In line with the distributed AGC demand distribution strategy, when the distributed AGC is distributed according to load rate sorting, the over-limit correction amount is also distributed according to load rate sorting; when the distributed AGC is distributed according to installed capacity, the over-limit correction amount is also distributed according to installed capacity. The over-limit correction amount (downward adjustment amount) of the 10kV and above distributed stations and low-voltage distributed 10kV aggregation units under the 10kV grid-connected point is obtained by distribution.

[0090] (2) AGC regulation demand correction.

[0091] When the AGC area total regulation demand and the over-limit correction amount are in the same direction, the regulation demand allocated to each AGC control unit (10kV and above distributed station or low-voltage distributed 10kV aggregation unit) is calculated as: ΔR k = -max(|ΔR k |,|ΔP crr,k |). In the formula: ΔR k is the corrected AGC regulation demand of control unit k, ΔR k is the initial AGC regulation demand of control unit k obtained by decomposition and distribution according to the set strategy, and ΔP crr,k is the over-limit adjustment amount of the 10kV load point decomposed to control unit k.

[0092] When the AGC area total regulation demand and the over-limit correction amount are in opposite directions, the AGC control units (10kV and above distributed stations and low-voltage distributed 10kV aggregation units) under the blocked equipment are all executed according to the distributed over-limit correction amount (downward adjustment amount), while the downward adjustment amount generated due to the blocking of the equipment is superimposed in the opposite direction to the AGC area total regulation demand, and then decomposed according to the inter-group distribution strategy and the intra-group distribution strategy. The control units participating in the over-limit correction do not participate in the decomposition and distribution of the total regulation demand of the region in this round, and the corrected AGC control unit (10kV and above distributed station and low-voltage distributed 10kV aggregation unit) regulation demand is obtained.

[0093] Based on the corrected AGC control unit regulation demand, the AGC control unit (10kV and above distributed station and low-voltage distributed 10kV aggregation unit) control target is generated.

[0094] Step 4: The 10kV and above distributed station control target is issued by the provincial AGC to the station for execution. When the provincial and local collaborative regulation is performed, the low-voltage distributed total control target is forwarded by the provincial AGC to the marketing side load control management system through the multi-element collaborative management system (deployed in the III regional control cloud), and the safety constraint of the low-voltage distributed 10kV aggregation unit is forwarded by the local AGC to the marketing side load control management system through the multi-element collaborative management system (deployed in the III regional control cloud). When the regional independent control is performed, the control target and safety constraint of the low-voltage distributed 10kV aggregation unit are both forwarded by the local AGC to the marketing side load control management system through the multi-element collaborative management system (deployed in the III regional control cloud), and are decomposed and issued to the low-voltage distributed photovoltaic user by the load control management system.

[0095] In the embodiment, the provincial and local distributed AGC generates the total regulation demand of the current level according to the selection of different regulation modes by the dispatching scenario.

[0096] The regulation mode is divided into the provincial and local collaborative regulation mode and the regional independent control mode according to whether it is the provincial centralized unified regulation.

[0097] The provincial and local collaborative regulation mode: used for the provincial unified regulation scenario such as whole network peak regulation, the total regulation demand is generated by the provincial distributed AGC, based on the regional distributed photovoltaic adjustable total installed capacity, total real-time output, total regulation upper limit, total regulation lower limit and other regional distributed aggregation information, the 10kV and above distributed photovoltaic regulation demand is decomposed and issued to each local dispatching, and then is decomposed and issued to the 10kV and above distributed photovoltaic station (resource layer) by each local dispatching for execution. At the same time, the low-voltage distributed total control target is forwarded to the marketing side load control management system, and then is decomposed and issued to the low-voltage distributed photovoltaic user (resource layer) by the marketing side load control management system for execution. In this mode, the regional distributed AGC distributed photovoltaic regional total regulation demand and low-voltage distributed total control target are both generated by the provincial distributed AGC, and the safety constraint is generated by the local dispatching.

[0098] The regional independent control mode: used for the regional regulation scenario such as regional partition balance control and cross-section flow control, the regional regulation demand is generated by the local distributed AGC, the 10kV and above distributed photovoltaic station regulation demand and 10kV load point low-voltage distributed aggregation unit regulation demand are generated by decomposition, the 10kV and above distributed photovoltaic station control target is directly issued to the distributed photovoltaic station for execution, the 10kV load point low-voltage distributed aggregation unit regulation demand and safety constraint are forwarded to the marketing side load control management system, and are decomposed and issued to the low-voltage distributed user for execution. In this mode, the regional distributed AGC distributed photovoltaic regional total regulation demand, low-voltage distributed control target and safety constraint are all generated by the local dispatching.

[0099] The embodiment provides a distributed photovoltaic scheduling method considering safety checking, which is based on a provincial and regional hierarchical collaborative control architecture, realizes distributed photovoltaic regulation safety checking and accurate regulation, and can balance power and regulate multiple scenes such as over-limit power flow.

[0100] Embodiment two

[0101] The embodiment two aims to provide a distributed photovoltaic scheduling system considering safety checking, which comprises the following steps of:

[0102] The PAS resource aggregation module is configured to: acquire low-voltage distributed aggregation information of a main grid 10kV load point forwarded by a multi-element collaborative management system and 10kV and above distributed field station information directly collected, further perform resource aggregation based on topology analysis, and obtain distributed photovoltaic aggregation information mounted under corresponding equipment according to dimensions of a main transformer, a bus, and a line.

[0103] The PAS scheduling safety checking module is configured to: acquire power grid operation mode, power transmission and transformation equipment limit value, and 10kV load point distributed photovoltaic aggregation information, perform base state power flow checking, and obtain equipment load rate; based on the equipment load rate and a set threshold value, calculate total distributed photovoltaic safety constraints under the equipment, including total maximum adjustment amount of the distributed photovoltaic under the equipment and total over-limit correction amount of the distributed photovoltaic under the equipment, and based on sensitivity analysis, calculate total distributed photovoltaic safety constraints under the 10kV load point (including total maximum adjustment amount of each load point and total over-limit correction amount of each load point).

[0104] The distributed AGC module is configured to: calculate regional regulation demand according to a set control mode, and generate control unit (10kV and above distributed field station and low-voltage distributed 10kV aggregation unit) regulation demand according to inter-group distribution strategy and intra-group distribution strategy. The 10kV load point distributed photovoltaic safety constraint total calculated by the PAS scheduling safety checking module is read according to a period, and control unit safety constraint total, including maximum adjustment amount and over-limit correction amount, is obtained by decomposition according to a certain distribution strategy, and control unit regulation demand is corrected to obtain each control unit control target, and is sent to a field station or a marketing side for execution.

Claims

1. A distributed photovoltaic scheduling method considering safety check, comprising: obtaining the limit value of power transmission and transformation equipment, load condition and equipment under distributed aggregation information, calculating the equipment load rate, and based on the equipment load rate, combining the threshold value, calculating the total maximum adjustment amount of the equipment under the distributed photovoltaic or the total over-limit correction amount of the equipment under the distributed photovoltaic, and then decomposing the total maximum adjustment amount or the total over-limit correction amount to obtain the total maximum adjustment amount of each load point or the total over-limit correction amount of each load point; based on the total maximum adjustment amount or the total over-limit correction amount of each load point, the maximum adjustment amount or the over-limit correction amount of each automatic generation control unit is decomposed, the adjustment demand of each automatic generation control unit is corrected, the control target of each automatic generation control unit is generated, and the control target is sent to each automatic generation control unit for execution.

2. The method of claim 1, wherein, The load point is determined as a 10kV load point according to the modeling boundary of the regional dispatching system, and the automatic generation control unit is a 10kV and above distributed station or a low-voltage distributed 10kV aggregation unit; The step of obtaining the equipment under distributed aggregation information includes: aggregating low-voltage distributed data to main network load points according to model membership relationship to obtain main network load point low-voltage distributed aggregation information, and then aggregating the main network load point low-voltage distributed aggregation information to each device of the main network through topological analysis to obtain the equipment under distributed aggregation information of each device.

3. The method of claim 1, wherein, The total maximum adjustment amount of the equipment under the distributed photovoltaic includes the maximum total downward adjustment amount of the equipment under the distributed photovoltaic; When the device is forward to the load rate is lower than the set threshold K1, the device under the distributed photovoltaic maximum total down When the device is positive to the load rate is higher than the set threshold K1, the device under the distributed photovoltaic maximum total down In the formulae, for the distributed photovoltaic maximum total down-regulation amount under the device d, Sd is the forward load ratio for device d e,d Sd is the operating limit for device d.

4. The method of claim 1, wherein, The total maximum adjustment amount of the equipment under the distributed photovoltaic includes the maximum total consumption amount of the equipment under the distributed photovoltaic; When the device reverse load rate is greater than 0 and lower than a set threshold value K2, the maximum total consumption of the device distributed photovoltaic When the device reverse load rate is greater than a set threshold value K2, the maximum total consumption of the device under the distributed photovoltaic In the formulae, For the device d under the distributed photovoltaic maximum total consumption, Sd is the inverse load rate for device d e,d Sd is the operating limit for device d.

5. The method of claim 1, wherein, The device under distribution of photovoltaic total over-limit correction quantity In the formula, ΔP crr,d The device d over-limit correction quantity; δ is the reserved safety margin; S e,d The running limit value set for the device d.

6. The method of claim 1, wherein, The decomposition of the total maximum adjustment amount or the total over-limit correction amount is performed according to the negative sensitivity of the equipment to the active power injection of the load point, and the safety constraint conditions of each voltage level device are checked and corrected in turn according to the priority from low voltage level to high voltage level to obtain the total maximum adjustment amount of each load point or the total over-limit correction amount of each load point.

7. The method of claim 1, wherein, The decomposition of the total maximum adjustment amount of the load point corresponds to different ways of distribution strategy within the distributed automatic generation control group; If the priority distribution strategy is selected for the distribution strategy within the distributed automatic generation control group, in each round, the total adjustment demand of the automatic generation control unit connected to the load point is calculated based on the initial adjustment demand of each automatic generation control unit, and it is checked whether the total adjustment demand exceeds the total maximum adjustment amount of the load point. When the initial adjustment demand is distributed to a certain automatic generation control unit, the total adjustment demand of the load point connected to the automatic generation control unit exceeds the total maximum adjustment amount, the automatic generation control unit is skipped, and no adjustment demand is distributed; until the total adjustment demand of the automatic generation control unit connected to the load point is completely distributed; If the installed capacity proportional distribution strategy is selected for the distribution strategy within the distributed automatic generation control group, the total maximum adjustment amount of the load point is distributed to the automatic generation control unit connected to the load point according to the installed capacity proportion; In each instruction cycle, the initial adjustment demand of each automatic generation control unit is corrected according to the adjustment step, capacity constraint and maximum adjustment amount of the automatic generation control unit.

8. The method of claim 1, wherein, The decomposition of the total over-limit correction amount of the load point is decomposed to the automatic generation control unit hung under the load point in the same way according to the group distribution strategy selected by the distributed automatic generation control, as the down-regulation amount of the automatic generation control unit.

9. The method of claim 1, wherein, When the total regulation demand of the automatic generation control area and the over-limit correction amount are in the same direction, the absolute value of the regulation demand of each automatic generation control unit is the maximum value between the absolute value of the initial regulation demand obtained by the decomposition according to the set strategy and the absolute value between the over-limit correction amount of the automatic generation control unit, and the direction of the regulation demand of the automatic generation control unit is down-regulation; When the total regulation demand of the automatic generation control area and the over-limit correction amount are in the opposite direction, the automatic generation control unit under the blocked equipment executes according to the distributed over-limit correction amount, and the down-regulation amount generated by the blocked equipment is superimposed in the opposite direction to the total regulation demand of the automatic generation control area, and then the total regulation demand of the automatic generation control area is decomposed according to the group distribution strategy and the group distribution strategy, and the control unit participating in the over-limit correction does not participate in the decomposition and distribution of the total regulation demand of the area in this round, to obtain the regulation demand of each automatic generation control unit.

10. A distributed photovoltaic scheduling system considering safety review, comprising: a scheduling safety review module configured to: obtain the limit value of power transmission and transformation equipment, load conditions and distributed aggregation information under the equipment, calculate the equipment load rate, and based on the equipment load rate, combined with the threshold value, calculate the total maximum regulation amount of distributed photovoltaic under the equipment or the total over-limit correction amount of distributed photovoltaic under the equipment, and then decompose the total maximum regulation amount or the total over-limit correction amount to obtain the total maximum regulation amount of each load point or the total over-limit correction amount of each load point; a distributed automatic generation control module configured to: based on the total maximum regulation amount or the total over-limit correction amount of each load point, decompose to obtain the maximum regulation amount or the over-limit correction amount of each automatic generation control unit, correct the regulation demand of each automatic generation control unit, generate the control target of each automatic generation control unit, and send it to each automatic generation control unit for execution.

11. The distributed photovoltaic scheduling system considering safety review of claim 10, further comprising a resource aggregation module configured to: aggregate low-voltage distributed data to main grid load points according to model membership relationship to obtain low-voltage distributed aggregation information of main grid load points, and then aggregate the low-voltage distributed aggregation information of main grid load points to each equipment of the main grid through topology analysis to obtain the distributed aggregation information under each equipment.

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