Method for quick response of reactive power in station based on over-allocation and overflow callback mechanism

Abstract

The application discloses a kind of based on the mechanism of over-allocation and overflow callback station reactive fast response method, the reactive source of station is classified, including classification planning A class fast response reactive source, B class slow response reactive source;According to the demand of reactive power, cooperate the A class fast response reactive source, B class slow response reactive source planned, distribution is carried out;Real-time monitoring after over-allocation A class fast response reactive source, B class slow response reactive source, and overflow judgment of station reactive total regulating amount is carried out;A class fast response reactive source is overflowed and is recalled, and the capacity of fast reactive source called excessively is released;After A class fast response reactive source overflow callback end, continue real-time monitoring A class fast response reactive source, B class slow response reactive source, and track the dynamic process of reactive regulation.The application realizes station fast reactive regulation, and considers response accuracy simultaneously.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of station reactive power response, and in particular to a station reactive power fast response method based on an over-allocated and overflow callback mechanism. BACKGROUND

[0002] With the continuous improvement of the penetration rate of new energy power generation, wind farms, photovoltaic power stations and other stations have become an important part of the power system, and the influence of the reactive voltage characteristics of the station on the stable operation of the power grid is increasingly significant. Therefore, the rapid balance and accurate control of reactive power are the core technical requirements for ensuring the voltage stability of the station grid connection point and improving the grid accommodation capacity.

[0003] Currently, wind farms, photovoltaic power stations, substations and other types of stations usually contain wind turbines, photovoltaic inverters, capacitors, reactors, static var generators (SVG) and other multi-element reactive sources to meet the reactive power regulation requirements under different operating conditions. At the same time, the source-side output volatility caused by high-proportion new energy access and the dynamic changes of power grid load exacerbate the randomness of reactive power demand.

[0004] The existing reactive power control method directly allocates the reactive power demand of the power grid to the reactive sources in the station in equal amounts, and the specific allocation method mainly includes two types. One type prioritizes the use of slow reactive sources, and the slow reactive sources in the station have a relatively long response time lag, resulting in slow reactive response of the station. The other type prioritizes the use of fast reactive sources, and uses slow reactive sources for reactive power replacement in the reactive power stable stage, which will result in the inability of fast reactive sources to release adjustment capacity in the fast-changing reactive power demand scenario, and will not be able to play a fast adjustment role in the subsequent adjustment process. The current station reactive power control method is difficult to adapt to real-time changes in reactive power demand under complex operating conditions, often resulting in "response lag", and even "reverse adjustment" in the fast-changing reactive power demand scenario, affecting the safe operation of the power grid voltage. Therefore, how to overcome the above problems is a problem that needs to be solved urgently. SUMMARY

[0005] The purpose of the present application is to overcome the problem that the prior art cannot meet the stringent requirements of high-proportion new energy access scenarios for station reactive power fast response. The station reactive power fast response method based on the over-allocated and overflow callback mechanism classifies the reactive sources of the station, and when the power grid needs the station to respond to reactive power, it quickly coordinates and controls according to the response characteristics of the adjustable reactive sources in the station, improves the station reactive response speed and accuracy, and has significant significance and good application prospects.

[0006] To achieve the above purpose, the present application provides the following technical scheme:

[0007] A station reactive power fast response method based on an over-allocated and overflow callback mechanism, comprising the following steps,

[0008] Step (A), classifying the reactive power sources of the station, including classifying and planning A type fast response reactive power sources and B type slow response reactive power sources;

[0009] Step (B), distributing the A type fast response reactive power sources and the B type slow response reactive power sources according to the demand of the reactive power, wherein the excess distribution of the B type slow response reactive power sources is the final expected adjustment reactive power amount corresponding thereto;

[0010] Step (C), real-time monitoring the A type fast response reactive power sources and the B type slow response reactive power sources after the excess distribution, and performing overflow judgment of the total adjustment amount of the station reactive power;

[0011] Step (D), if there is overflow, performing overflow callback of the A type fast response reactive power sources to release the excess called fast reactive power source capacity;

[0012] Step (E), after the overflow callback of the A type fast response reactive power sources is completed, returning to Step (C) to continue real-time monitoring the A type fast response reactive power sources and the B type slow response reactive power sources after the excess distribution, and performing overflow judgment of the total adjustment amount of the station reactive power, and tracking the dynamic process of the reactive power adjustment.

[0013] Preferably, in Step (A), the A type fast response reactive power sources are reactive power sources with fast response speed and capable of realizing steady-state fast scheduling and emergency scheduling, including SVGs with fast reactive power adjustment capability, wind turbines capable of fast response, photovoltaic inverters, and phase modulators.

[0014] The B type slow response reactive power sources are reactive power sources with relatively slow response speed and capable of bearing steady-state replacement control and emergency scheduling auxiliary functions, including capacitors and reactors with slow reactive power adjustment capability and wind turbines incapable of fast reactive power response.

[0015] Preferably, in Step (B), the A type fast response reactive power sources and the B type slow response reactive power sources are distributed according to the demand of the reactive power, including the following steps.

[0016] (B1), according to the demand of the reactive power, the demand including the requirement of the receiving power grid for the reactive power adjustment of the station or real-time collection of the operation data of the station, calculating the total amount of the reactive power adjustment required by the station to meet the operation requirement of the power grid under the current working condition according to formula (1) ,

[0017] (1)

[0018] wherein, is the voltage reactive power sensitivity coefficient, i.e. the reactive power required to increase by a unit voltage; is the target value of the grid-connected point voltage issued by the power grid to the station, the actual voltage value of the current grid-connected point;

[0019] (B2), according to the total amount of reactive power regulation required by the station , the A type fast response reactive power source is distributed, ; the B type slow response reactive power source is normally distributed, wherein, , respectively, the maximum adjustable capacity of the A and B type reactive power sources, wherein the excess distribution of the B type slow response reactive power source is the final expected regulation reactive power amount corresponding thereto;

[0020] Or according to the on-site operation demand, the B type slow response reactive power source is distributed, the maximum fast response capacity reserve is maintained, and the adjustment scheme of the slow response reactive power source is distributed, and the reactive power capacity is , wherein, is the real-time reactive power output of the A type fast response reactive power source, is the ideal regulation amount of the A type fast response reactive power source under the output return 0 target.

[0021] Preferably, according to the total amount of reactive power regulation required by the station , the A type fast response reactive power source is distributed, and the B type slow response reactive power source is distributed, and the two are distributed at the same time.

[0022] Preferably, step (C), real-time monitoring of the A type fast response reactive power source and the B type slow response reactive power source after excess distribution, and overflow judgment of the total reactive power regulation amount of the station, including the following steps,

[0023] (C1), real-time monitoring of the station reactive power output: continuously collecting the actual output of the A type and B type reactive power sources, and calculating the real-time total reactive power output of the station , tracking the dynamic process of reactive power regulation, wherein, , is the real-time output of the monitored A type and B type reactive power sources;

[0024] (C2) judges whether the station output is overflowed:

[0025] The real-time total reactive power output of the station is compared with the total amount of reactive power regulation required by the station , to determine whether is satisfied, if so, the reactive power overflow occurs, wherein is the reactive power adjustment dead zone, provides a basis for triggering the subsequent return mechanism, and the reactive power adjustment dead zone can be set according to the on-site demand, The value of the first parameter is greater than zero.

[0026] Preferably, in order to reduce the degree of voltage overshoot caused by the overflow of the reactive power output of the field station, when judging whether the output of the field station is overflowed, a conservative coefficient can be set, and a conservative judgment is made according to formula (2),

[0027] (2)

[0028] wherein, the conservative coefficient, .

[0029] Preferably, in step (D), if there is overflow, the overflow callback is performed on the A type fast response reactive power source to release the capacity of the fast reactive power source that is excessively called, including the following steps,

[0030] (D1), according to formula (3), the total overflow amount of the A type fast response reactive power source is calculated :

[0031] (3)

[0032] (D2), the output of the A type fast response reactive power source is reduced according to a set step size, or the output of the A type fast response reactive power source is directly reduced:

[0033] If the output of the A type fast response reactive power source is reduced by a set step size, the output adjustment amount of the A type fast response reactive power source is expressed as wherein, the set step size, is the time corresponding to the next callback instruction period;

[0034] If the output of the A type fast response reactive power source is directly reduced, the output adjustment amount of the A type fast response reactive power source is expressed as .

[0035] The beneficial effects of the present application are: the field station reactive power fast response method based on the over-allocation and overflow callback mechanism classifies the reactive power sources of the field station, and when the power grid needs the field station to respond to the reactive power, the response characteristics of the adjustable reactive power sources in the station are used for fast coordination control, so that the speed and accuracy of the reactive power response of the field station are improved, the field station reactive power fast response and dynamic reactive power callback are performed through the over-allocation and overflow callback mechanism, and the present application has significant significance and good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a flowchart of the field station reactive power fast response method based on the over-allocation and overflow callback mechanism of the present application;

[0037] Figure 2 is a field station reactive power response result graph of an embodiment under scenario 1 of the present application;

[0038] Figure 3 The reactive power response result diagram of the station for the embodiment under the scenario 2 of the application. DETAILED DESCRIPTION

[0039] The application will be further described below with reference to the accompanying drawings.

[0040] The station reactive power fast response method based on the over-allocation and overflow callback mechanism of the application, as shown in the figure, comprises the following steps, Figure 1

[0041] Step (A), classifying the reactive power sources of the station, comprising classifying the A type fast response reactive power sources and the B type slow response reactive power sources, wherein,

[0042] The A type fast response reactive power sources are the reactive power sources with fast response speed and capable of realizing steady-state fast scheduling and emergency scheduling, comprising the SVG with fast reactive power regulation capability, the fan capable of fast response, the photovoltaic inverter, the phase modifier and other power equipment with fast reactive power regulation capability;

[0043] The B type slow response reactive power sources are the reactive power sources with relatively slow response speed and capable of bearing steady-state replacement control and emergency scheduling auxiliary function, comprising the capacitor reactor, the fan incapable of fast reactive power response and other power equipment with slow reactive power regulation capability;

[0044] Step (B), distributing according to the demand of the reactive power, cooperating with the A type fast response reactive power sources and the B type slow response reactive power sources, comprising the following steps,

[0045] (B1), according to the demand of the reactive power, the demand comprising the reactive power regulation requirement of the receiving power grid to the station or the real-time collection of the station operation data, calculating the total amount of the reactive power regulation required by the station to meet the operation requirement of the power grid under the current working condition according to formula (1) ,

[0046] (1)

[0047] Among them, is the voltage reactive power sensitivity coefficient, that is, the reactive power required to be increased by lifting a unit voltage; is the target value of the grid-connected point voltage issued by the power grid to the station, is the actual voltage value of the current grid-connected point;

[0048] (B2), according to the total amount of the reactive power regulation required by the station , distributing the A type fast response reactive power sources, ; normally distributing the B type slow response reactive power sources, Among them,​ , respectively A, B class reactive power source maximum adjustable capacity, wherein the normal distribution of B class slow response reactive power source is its corresponding final desired regulation of reactive power, the normal distribution of B class slow response reactive power source can have a variety of distribution methods, which can be adjusted according to the field demand, and according to the total amount of reactive power regulation required by the station , A class fast response reactive power source distribution, B class slow response reactive power source distribution, both are simultaneously distributed, one embodiment is that according to the field operation demand, the reactive power distribution of B class slow response reactive power source can keep the maximum fast response capacity reserve as the target, and the adjustment scheme of slow reactive power source distribution is , , wherein, is the real-time reactive power output of A class fast response reactive power source, is the ideal regulation amount of A class fast response reactive power source under the target of output back to 0;

[0049] Step (C), real-time monitoring of A class fast response reactive power source and B class slow response reactive power source after over-distribution, and judging the overflow of the total reactive power regulation amount of the station, including the following steps,

[0050] (C1), real-time monitoring of the station reactive power output: continuously collecting the actual output of A class and B class reactive power source, and calculating the real-time total reactive power output of the station , tracking the dynamic process of reactive power regulation, wherein, , is the real-time output of the monitored A class and B class reactive power source;

[0051] (C2) judge whether the station output is overflowed:

[0052] Compare the real-time total reactive power output of the station with the total amount of reactive power regulation required by the station , to determine whether , if satisfied, the reactive power overflow occurs, wherein is the reactive power adjustment dead zone, is the basis for triggering the subsequent callback mechanism, and the reactive power adjustment dead zone can be set according to the field demand, The value of is greater than zero;

[0053] The B class slow response reactive power source of the present application will not appear overflow condition, because the final stable adjustment scheme is to preferentially use slow reactive power source, that is, the final adjustment amount of the B class slow response reactive power source is min (adjustment capacity of the B class slow response reactive power source, total adjustment demand of the station), and the remaining insufficient total reactive power adjustment of the station is supplemented by the A class fast response reactive power source. In the initial reactive power distribution scheme of the present application, the adjustment scheme of the A class fast response reactive power source is the reactive power output exceeding the final adjustment amount, that is, there is overflow; the adjustment scheme of the B class slow response reactive power source is the final output result, so there is no overflow problem.

[0054] In order to reduce the voltage overshoot degree caused by the overflow of the station reactive power output, when judging whether the station output is overflow, a conservative coefficient can be set, and the conservative judgment is made according to formula (2),

[0055] (2)

[0056] Among them, is a conservative coefficient, ;

[0057] Step (D), if there is overflow, the A class fast response reactive power source is overflowed back to release the excessive called fast reactive power source capacity, including the following steps,

[0058] (D1), according to formula (3), the total overflow amount of the A class fast response reactive power source is calculated :

[0059] (3)

[0060] (D2), the output of the A class fast response reactive power source is reduced according to the set step length, or directly reduced:

[0061] If the output of the A class fast response reactive power source is reduced by the set step length, the output adjustment amount of the A class fast response reactive power source is expressed as , wherein, is a set step length, is the time corresponding to the next callback instruction period;

[0062] If the output of the A class fast response reactive power source is directly reduced, the output adjustment amount of the A class fast response reactive power source is expressed as ;

[0063] Step (E), after the overflow callback of the A class fast response reactive power source is finished, return to step (C) to continue to monitor the A class fast response reactive power source and the B class slow response reactive power source after the excessive distribution, and to judge the overflow of the total reactive power adjustment of the station, and to track the dynamic process of the reactive power adjustment.

[0064] According to the station reactive power fast response method based on the over-allocation and overflow callback mechanism of the application, the effectiveness of the proposed reactive power fast response method is verified through simulation analysis, and the setting example parameters are shown in Table 1, and the conservative coefficient is not considered in the present example .

[0065] Table 1: Example scene parameters of the application

[0066] Scenario Number Fast reactive source capacity (Mvar) Slow reactive source capacity (Mvar) Grid reactive regulation demand (Mvar) 1 10 15 20 2 10 20 20

[0067] Under the above scenarios 1 and 2, the application of the method proposed in the application and the non-application of the corresponding station reactive response are used, wherein the cumulative reactive deviation is used to quantitatively evaluate the reactive response of the station, and the cumulative reactive deviation calculation formula is as follows,

[0068]

[0069] From Figure 2 and Figure 3 It can be seen that by applying the method proposed in the application, the tracking of the station to the reactive demand instruction is better, wherein under scenario 1, the cumulative reactive deviation is reduced from 52.5Mvars to 25Mvars; and under scenario 2, the cumulative reactive deviation is reduced from 90Mvars to 35Mvars.

[0070] In summary, the station reactive power fast response method based on the over-allocation and overflow callback mechanism of the application classifies the reactive power sources of the station, and when the power grid needs the station to respond to the reactive power, the station is quickly coordinated and controlled according to the response characteristics of the adjustable reactive power source in the station, so as to improve the station reactive response speed and accuracy. The application has significant significance and good application prospect through the over-allocation, overflow callback mechanism for station reactive power fast response and dynamic reactive power callback.

[0071] The basic principles, main features and advantages of the application are shown and described above. It should be understood by those skilled in the art that the application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the application. Without departing from the spirit and scope of the application, various changes and improvements can be made to the application, and these changes and improvements all fall within the scope of the claimed application. The scope of protection of the application is defined by the appended claims and their equivalents.

Claims

1. A method for fast reactive power response of substation based on over allocation and spill back mechanism, characterized in that: The method comprises the following steps, Step (A), classifying the reactive power sources of the substation, including classifying and planning A type fast-response reactive power sources and B type slow-response reactive power sources; Step (B), distributing the A type fast-response reactive power sources and the B type slow-response reactive power sources according to the demand for reactive power, wherein the excess distribution of the B type slow-response reactive power sources is the final expected adjustment reactive power amount corresponding to the B type slow-response reactive power sources; Step (C), monitoring the A type fast-response reactive power sources and the B type slow-response reactive power sources in real time after the excess distribution and performing overflow judgment on the total adjustment amount of the reactive power of the substation; Step (D), if there is overflow, performing overflow callback on the A type fast-response reactive power sources to release the capacity of the fast-response reactive power sources that are excessively called; Step (E), after the overflow callback on the A type fast-response reactive power sources is completed, returning to step (C) to continue monitoring the A type fast-response reactive power sources and the B type slow-response reactive power sources in real time after the excess distribution and performing overflow judgment on the total adjustment amount of the reactive power of the substation, and tracking the dynamic process of the reactive power adjustment, In step (A), the A type fast-response reactive power sources are reactive power sources with fast response speed and capable of realizing steady-state fast scheduling and emergency scheduling, including SVGs with fast reactive power adjustment capability, wind turbines capable of fast response, photovoltaic inverters and phase modulators; The B type slow-response reactive power sources are reactive power sources with relatively slow response speed and capable of realizing steady-state replacement control and emergency scheduling auxiliary functions, including capacitors and reactors with slow reactive power adjustment capability and wind turbines incapable of fast reactive power response; In step (B), the A type fast-response reactive power sources and the B type slow-response reactive power sources are distributed according to the demand for reactive power, including the following steps, (B1), according to the demand of reactive power, which includes the reactive power regulation requirement of the receiving power grid to the station, or real-time collection of station operation data, according to formula (1), the total amount of reactive power regulation required by the station to meet the operation requirements of the power grid under the current working condition , （1） wherein, is the voltage reactive sensitivity coefficient, i.e. the reactive power required to be increased by a unit voltage rise; is the target value of the grid-connected point voltage issued by the grid to the station, is the actual voltage value of the grid-connected point at present; (B2) according to the total amount of reactive power regulation required by the substation , the A type fast response reactive power sources are allocated, ; the B type slow response reactive power sources are normally allocated, , wherein, , are respectively the maximum adjustable capacities of the A type and B type reactive power sources, wherein the over-allocation of the B type slow response reactive power sources is the corresponding final expected regulation reactive power amount. Or according to the on-site operation demand, the reactive power distribution is carried out on the B type slow response reactive power source, the maximum fast response capacity reserve is maintained as the target, and the adjustment scheme of the slow reactive power source is distributed , , is the real-time reactive power output of the A type fast response reactive power source, is the ideal adjustment amount of the A type fast response reactive power source under the output return 0 target.

2. The method of claim 1, wherein the method is based on an over- allocation and spillback mechanism. According to the total amount of reactive power regulation required by the station The A type fast response reactive power source is allocated, and the B type slow response reactive power source is allocated, and the two are allocated simultaneously.

3. The method of claim 1, wherein the method further comprises: determining if the reactive power demand is greater than the reactive power capability of the power supply; and if the reactive power demand is greater than the reactive power capability of the power supply, then increasing the reactive power capability of the power supply by a predetermined amount. In step (C), the A type fast-response reactive power sources and the B type slow-response reactive power sources after the excess distribution are monitored in real time, and overflow judgment is performed on the total adjustment amount of the reactive power of the substation, including the following steps, (C1), real-time monitoring of the reactive power output of the station: continuously collecting the actual output of the A-type and B-type reactive power sources and calculating the real-time total reactive power output of the station , tracking the dynamic process of reactive power regulation, wherein 、 is the real-time output of the monitored A-type and B-type reactive power sources; (C2) judging whether the output of the substation is overflowed: The real-time total reactive power output of the substation The total amount of reactive power regulation required by the substation The comparison is made to determine whether the condition is met If the condition is met, the reactive power overflow occurs, wherein The reactive power adjustment dead zone is greater than zero. The reactive power adjustment dead zone provides a basis for triggering the subsequent callback mechanism The reactive power adjustment dead zone can be set according to the on-site demand The value of the reactive power adjustment dead zone is greater than zero.

4. The method of claim 3, wherein the method further comprises: In order to reduce the voltage overshoot degree caused by the overflow of the reactive power output of the substation, when judging whether the output of the substation is overflowed, a conservative coefficient can be set, and conservative judgment is performed according to formula (2), （2） wherein is a conservation coefficient, .

5. The method of claim 4, wherein the method further comprises: Step (D), if there is overflow, performing overflow callback on the A type fast-response reactive power sources to release the capacity of the fast-response reactive power sources that are excessively called, including the following steps, (D1) Calculate the total amount of spill of the A-type fast-response reactive power source according to formula (3) : （3） (D2), reducing the output of the A type fast-response reactive power sources according to a predetermined step length or directly reducing the output of the A type fast-response reactive power sources: If the output of the A-type fast response reactive power source is adjusted by a set step, the output adjustment amount of the A-type fast response reactive power source is expressed as wherein, is a set step, is a corresponding time of a next callback instruction period. Directly down-regulation, the output adjustment amount of the A type fast response reactive power source is expressed as .

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