Method and device for adjusting reactive power control limit of substation

Abstract

The application provides a substation reactive power control limit value adjustment method and device, through a first reactive power limit value interval, a second reactive power limit value interval, a control switching threshold value and a preset condition, a target reactive power control limit value interval of the current substation reactive power control is determined, that is, the automatic switching of the reactive power limit value interval based on the control mode switching threshold value, the dynamic setting of the reactive power control limit value is realized. When the active load of the substation is low, the reactive power limit value calculation is too small, which leads to the problem of reactive power control lockout, according to the different load operation states of the substation, the dynamic setting of the reactive power limit value is carried out, a more reasonable reactive power limit value interval is given, and the problem of reactive power control lockout caused by unreasonable limit value is avoided, the application can improve the operation control effect of the substation, has engineering practicability, and has a remarkable effect on supporting the economic operation of the power grid.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of reactive power control limit adjustment, and particularly relates to a method and device for adjusting reactive power control limit of a substation. BACKGROUND

[0002] In recent years, with the continuous access of new energy such as wind power and energy storage, due to the intermittent and strong randomness of new energy output, the active load of the substation connected to the power grid presents a sharp volatility, especially when the new energy is in a high output period, the load of the substation drops to a low point, which has an adverse effect on reactive power control.

[0003] The conventional reactive power control method of the substation generally adopts a power factor limit constraint mode, that is, by setting a power factor limit, the reactive power control limit is calculated according to the active load of the substation and the power factor limit, and when the reactive load of the substation exceeds the limit interval, the capacitor or reactor on the low-voltage side of the substation is put into operation or removed to realize the local balance of reactive power. When the active load of the substation is affected by the new energy and sharply decreases, the reactive power limit interval is also affected and continuously shrinks, eventually leading to a limit interval smaller than the capacity value of a single group of capacitors and reactors. At this time, no matter whether the capacitors and reactors are put into operation or removed, the reactive power cannot be constrained within the limit interval, and the reactive power control presents a "locked" state. SUMMARY

[0004] In order to solve the above technical problems, the present application is proposed. Embodiments of the present application provide a method and device for adjusting the reactive power control limit of a substation, which solves the problem of reactive power control lock caused by a small limit bandwidth.

[0005] According to one aspect of the present application, a method for adjusting the reactive power control limit of a substation is provided, which comprises: obtaining a power factor limit interval and a reactive power limit conversion interval; calculating a first reactive power limit interval according to the current active power of the substation and the power factor limit interval; determining a coefficient value of the reactive power limit conversion interval according to the principle of reactive power backfeed, wherein the principle of reactive power backfeed indicates that the reactive power of the substation flows back to a high voltage level; performing adjustable reactive power margin calculation according to the topology operation mode of the substation to obtain an adjustable reactive power margin; calculating a second reactive power limit interval according to the reactive power lower limit in the second reactive power limit interval, the power factor lower limit in the power factor limit interval, and the coefficient value and the adjustable reactive power margin value; calculating a control switching threshold according to the reactive power lower limit in the second reactive power limit interval and the power factor lower limit in the power factor limit interval; and determining a target reactive power control limit interval of the current substation during reactive power control according to the first reactive power limit interval, the second reactive power limit interval, the control switching threshold, and a preset condition.

[0006] In an embodiment, the method further comprises:

[0007] If the active power is greater than the control mode switching threshold, determining the target reactive power control limit interval for the current substation reactive power control as a first target reactive power control limit interval;

[0008] If the active power is less than or equal to the control mode switching threshold, determining the target reactive power control limit interval for the current substation reactive power control as a second target reactive power control limit interval.

[0009] In an embodiment, the method further comprises:

[0010] performing adjustable reactive power margin calculation according to the substation topology operation mode to obtain an adjustable reactive power margin; wherein the substation topology operation mode represents the connection mode of incoming lines, buses, transformers, capacitors, reactors, loads, and outgoing lines in the current substation.

[0011] In an embodiment, the method further comprises:

[0012] performing descending order arrangement of capacitors and reactors in the current substation according to absolute values of capacities to obtain an arrangement sequence;

[0013] sequentially performing state evaluation on each capacitor and each reactor in the arrangement sequence according to the arrangement sequence to obtain an evaluation result;

[0014] deleting abnormal capacitors and abnormal reactors in the arrangement sequence according to the evaluation result to obtain a target arrangement sequence;

[0015] selecting the absolute value of the capacity corresponding to the first column in the target arrangement sequence as the adjustable reactive power margin.

[0016] In an embodiment, the method further comprises:

[0017] If the current substation reactive power flows to a high voltage level, determining the coefficient value as a first threshold value;

[0018] If the current substation prohibits the reactive power from flowing to a high voltage level, determining the coefficient value as a second threshold value.

[0019] In an embodiment, the method further comprises:

[0020] obtaining an operation curve of a substation;

[0021] dividing the operation curve into a plurality of time periods according to peak, valley, flat peak, uphill and downhill to obtain a peak time period, a valley time period, a flat peak time period, an uphill time period and a downhill time period;

[0022] setting power factor upper limit values and power factor lower limit values for the peak time period, the valley time period, the flat peak time period, the uphill time period and the downhill time period respectively according to start time and end time of each time period;

[0023] setting the power factor limit value interval according to the plurality of power factor upper limit values and the plurality of power factor lower limit values.

[0024] In an embodiment, the power factor upper limit value is cosf max , and the power factor lower limit value is cosf min , wherein the setting of the power factor upper limit values and the power factor lower limit values for the peak time period, the valley time period, the flat peak time period, the uphill time period and the downhill time period respectively according to start time and end time of each time period comprises:

[0025] setting power factor upper limit values and power factor lower limit values for the peak time period, the valley time period, the flat peak time period, the uphill time period and the downhill time period respectively according to start time and end time of each time period; wherein the setting range of the power factor upper limit values and the power factor lower limit values is:

[0026] 0<cosf min <1;

[0027] 0<cosf max ≤1;

[0028] The setting of the power factor limit value interval according to the plurality of power factor upper limit values and the plurality of power factor lower limit values comprises:

[0029] setting the power factor limit value interval according to the plurality of power factor upper limit values and the plurality of power factor lower limit values; wherein the power factor limit value interval is denoted as [cosf min ,cosf max ].

[0030] In an embodiment, P is the active power of the current substation, [Q dn,nom ,Q up,nom ] is the reactive power limit interval, Q up,nom is the upper limit of reactive power, and Q dn,noma first reactive power limit interval, wherein the first reactive power limit interval is calculated according to the current substation active power and the power factor limit interval, and the calculation formula is:

[0031]

[0032]

[0033] In an embodiment, the control mode switching threshold P des , and the calculation formula of the control switching threshold is calculated according to the reactive power lower limit in the second reactive power limit interval and the power factor lower limit in the power factor limit interval.

[0034]

[0035] According to another aspect of the present application, a device for adjusting substation reactive power control limit is provided, comprising: an obtaining module for obtaining a power factor limit interval and a reactive power limit conversion interval; a calculation module for calculating a first reactive power limit interval according to the current substation active power and the power factor limit interval; a determination module for determining a coefficient value of the reactive power limit conversion interval according to a reactive power return principle; wherein the reactive power return principle indicates that the reactive power of the substation flows back to a high voltage level; an adjustable module for calculating an adjustable reactive power margin to obtain an adjustable reactive power margin according to a substation topology operation mode; an interval module for calculating a second reactive power limit interval according to the reactive power limit conversion interval, the coefficient value and the adjustable reactive power margin value; a threshold module for calculating a control switching threshold according to the reactive power lower limit in the second reactive power limit interval and the power factor lower limit in the power factor limit interval; and a condition module for determining a target reactive power control limit interval of the current substation reactive power control according to the first reactive power limit interval, the second reactive power limit interval, the control switching threshold and a preset condition.

[0036] According to another aspect of the present application, a computer readable storage medium is provided, and the storage medium stores a computer program for executing the above-mentioned control method of low frequency load shedding based on power grid.

[0037] The application provides a substation reactive power control limit adjustment method and device, including: obtaining a power factor limit interval and a reactive power limit conversion interval, calculating a first reactive power limit interval according to the current substation active power and the power factor limit interval, determining a coefficient value of the reactive power limit conversion interval according to the reactive power return principle, wherein the reactive power return principle indicates that the reactive power of the substation flows to a high voltage level, calculating an adjustable reactive power margin according to the substation topology operation mode to obtain the adjustable reactive power margin, calculating a second reactive power limit interval according to the reactive power limit conversion interval, the coefficient value and the adjustable reactive power margin value, calculating a control switching threshold according to the lower limit of the reactive power in the second reactive power limit interval and the lower limit of the power factor in the power factor limit interval, and determining a target reactive power control limit interval of the current substation reactive power control according to the first reactive power limit interval, the second reactive power limit interval, the control switching threshold and a preset condition. The target reactive power control limit interval of the current substation reactive power control is determined through the first reactive power limit interval, the second reactive power limit interval, the control switching threshold and the preset condition, that is, the automatic switching of the reactive power limit interval based on the control mode switching threshold, realizing the dynamic setting of the reactive power control limit. The application can improve the operation control effect of the substation, has engineering practicability, and has a remarkable effect on supporting the economic operation of the power grid. BRIEF DESCRIPTION OF DRAWINGS

[0038] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description of embodiments of the present application taken in conjunction with the accompanying drawings. The drawings provided in the present application are used to provide a further understanding of embodiments of the present application, and constitute a part of the specification, and are used to explain the present application together with embodiments of the present application, and do not constitute a limitation of the present application. In the drawings, the same reference numerals generally represent the same components or steps.

[0039] Figure 1 FIG. 1 is a flowchart of a substation reactive power control limit adjustment method provided by an exemplary embodiment of the present application.

[0040] Figure 2 FIG. 2 is a structural diagram of a substation topology operation mode provided by an exemplary embodiment of the present application.

[0041] Figure 3 FIG. 3 is a flowchart of a target reactive power control limit interval determination method provided by an exemplary embodiment of the present application.

[0042] Figure 4is a flowchart of a method for adjusting reactive power control limits of a substation according to another example embodiment of the present application.

[0043] Figure 5 is a structural diagram of a device for adjusting reactive power control limits of a substation according to another example embodiment of the present application.

[0044] Figure 6 is a structural diagram of a device for adjusting reactive power control limits of a substation according to another example embodiment of the present application.

[0045] Figure 7 is a structural diagram of an electronic device according to an example embodiment of the present application. DETAILED DESCRIPTION

[0046] Hereinafter, example embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part but not all of the embodiments of the present application. It should be understood that the present application is not limited to the described embodiments.

[0047] Figure 1 is a flowchart of a method for adjusting reactive power control limits of a substation according to an example embodiment of the present application. Figure 2 is a structural diagram of a substation topology operating mode according to an example embodiment of the present application. As shown in the figure, the method for adjusting reactive power control limits of a substation includes: Figures 1-2

[0048] Step 110: Obtain a power factor limit interval and a reactive power limit conversion interval.

[0049] The power factor limit interval is denoted as [cosf min ,cosf max ], the reactive power limit conversion interval is denoted as [K1×γ min ,K2×γ max ], γ max is a maximum conversion percentage, γ min is a minimum conversion percentage, which is a percentage of the reactive power limit of the substation relative to the adjustable reactive power margin, and K1 and K2 are reverse sending coefficients.

[0050] In the embodiment of the present application, "obtaining a power factor limit interval" includes:

[0051] (11) Obtain an operating curve of the substation.

[0052] (12) Divide the operating curve into multiple time periods in terms of peak, valley, flat peak, uphill and downhill to obtain a peak time period, a valley time period, a flat peak time period, an uphill time period and a downhill time period.

[0053] ​(13) According to the start time and the end time of each time period, the peak time period, the valley time period, the flat peak time period, the uphill time period and the downhill time period are respectively set with the power factor upper limit value and the power factor lower limit value.

[0054] (14) According to the plurality of power factor upper limit values and the plurality of power factor lower limit values, the power factor limit value interval is set.

[0055] The power factor limit value is the power factor upper limit and lower limit value of the time period point of the whole day regulated by the power grid dispatching, generally divided into a plurality of time periods according to the peak, the valley, the flat peak, the uphill and the downhill, and the whole day is divided into a plurality of time periods according to the "start time, end time", and the power factor upper limit cosf max and the power factor lower limit value cosf min are set in each time period. And there is a setting regulation:

[0056] 0<cosf min <1;

[0057] 0<cosf max ≤1.

[0058] As shown in the following Table 1:

[0059]

[0060] Step 120: According to the active power of the current substation and the power factor limit value interval, a first reactive power limit value interval is calculated.

[0061] In the embodiment of the application, according to the active power of the current substation and the power factor limit value interval, a first reactive power limit value interval is calculated, which includes:

[0062] P is the active power of the substation, generally the total active power of the high voltage side of the transformer, unit: MW. The first reactive power limit value interval [Q dn,nom , Q up,nom ] refers to the upper limit of reactive power Q up,nom and the lower limit of reactive power Q dn,nom , unit: MVar. The calculation formula is as follows:

[0063]

[0064]

[0065] Step 130: According to the reactive power return principle, the coefficient value of the reactive power limit value conversion interval is determined, wherein the reactive power return principle indicates that the reactive power of the substation flows to the high voltage level.

[0066] In the reactive power limit value conversion interval, γ max is the maximum conversion percentage, γ minThe minimum percentage is a percentage of reactive power limit of the substation relative to the adjustable reactive power margin, and K1 and K2 are reverse sending coefficients. The reverse sending refers to the phenomenon that the reactive power of the substation flows back to the high voltage level. When the reactive power of the substation needs to be sent to the upper level, the values of K1 and K2 are -1; when the reactive power of the substation is prohibited to be sent to the upper level, the values of K1 and K2 are 1.

[0067] Step 140: According to the substation topology operation mode, the adjustable reactive power margin is calculated to obtain the adjustable reactive power margin.

[0068] The substation topology operation mode mainly refers to the main wiring type of the substation, including the connection modes of incoming lines, buses, transformers, capacitors, reactors, loads and outgoing lines. Typical substation topology operation modes are as follows Figure 2 The adjustable reactive power margin of the substation is mainly based on the topology operation mode, and is generally calculated based on the capacity of the capacitors and reactors connected to the low voltage side of the transformer. The specific evaluation and calculation method is as follows:

[0069] First, the number of capacitors and reactors in the substation is counted, and the capacitors and reactors are arranged in descending order according to the absolute value of the capacity to form a queue. Then, the state of each capacitor and reactor is evaluated according to the queue order. When there are bad data such as cold standby, abnormal telemetry value, abnormal switch remote signaling value, maintenance sign, etc. for the capacitor and reactor, the device is excluded from the queue. Finally, the absolute value of the capacity recorded in the first queue after the evaluation is completed as the adjustable reactive power margin Q regul (unit: Mvar, megavolt-ampere).

[0070] Step 150: According to the reactive power limit conversion interval, the coefficient value and the adjustable reactive power margin value, the second reactive power limit interval is calculated.

[0071] The calculation formula of the second reactive power limit interval [Q dn,cov ,Q up,cov ] is as follows:

[0072] Q up,cov = Q regul × K2 × γ max ;

[0073] Q dn,cov = Q regul × K1 × γ min .

[0074] In the formula, Q up,cov is the upper limit of the reactive power, and Q up,cov is the lower limit of the reactive power, with the unit of MVar.

[0075] Step 160: According to the lower limit of the reactive power in the second reactive power limit interval and the lower limit of the power factor in the power factor limit interval, the control switching threshold is calculated.

[0076] Control mode switching threshold P des The calculation formula is as follows:

[0077]

[0078] In the formula, P des is a control mode switching threshold, in MW. Q up_cov is a converted mode reactive power lower limit in step 5, in MVar. cosf min is a power factor lower limit value.

[0079] Step 170: determining a target reactive power control limit interval of the current substation in reactive power control according to the first reactive power limit interval, the second reactive power limit interval, the control switching threshold, and a preset condition.

[0080] The application provides a substation reactive power control limit adjustment method and device, comprising: obtaining a power factor limit interval and a reactive power limit conversion interval, calculating a first reactive power limit interval according to a current substation active power and the power factor limit interval, determining a coefficient value of the reactive power limit conversion interval according to a reactive power return principle, wherein the reactive power return principle indicates that the reactive power of the substation flows back to a high voltage level, performing adjustable reactive power margin calculation according to a substation topology operation mode to obtain an adjustable reactive power margin, calculating a second reactive power limit interval according to the reactive power limit conversion interval, the coefficient value, and the adjustable reactive power margin value, calculating a control switching threshold according to a reactive power lower limit in the second reactive power limit interval and a power factor lower limit value in the power factor limit interval, and determining a target reactive power control limit interval of the current substation in reactive power control according to the first reactive power limit interval, the second reactive power limit interval, the control switching threshold, and a preset condition. The target reactive power control limit interval of the current substation in reactive power control is determined through the first reactive power limit interval, the second reactive power limit interval, the control switching threshold, and the preset condition, that is, the automatic switching of the reactive power limit interval based on the control mode switching threshold, so as to realize the dynamic setting of the reactive power control limit. The reactive power limit value is calculated to be too small when the active load of the substation is low, which leads to the problem of reactive power control lockout. According to different load operation states of the substation, the dynamic setting of the reactive power limit is performed, a more reasonable reactive power limit interval is given, and the problem of reactive power control lockout caused by unreasonable limit value is avoided. The application can improve the operation control effect of the substation and has engineering practicability, and has a remarkable effect on supporting the economic operation of the power grid.

[0081] Figure 3 is a flowchart of a target reactive power control limit interval determination method provided by an exemplary embodiment of the application. As shown in Figure 3 , step 170 can comprise:

[0082] Step 171: If the active power is greater than the control mode switching threshold, it is determined that the target reactive power control limit interval for the current substation is the first target reactive power control limit interval.

[0083] The current substation active power P is compared. When the active power P is higher than the control mode switching threshold P des , the reactive power control uses the limit interval [Q dn,nom , Q up,nom ]. When the substation active power P is lower than or equal to the control mode switching threshold P des , the reactive power control uses the limit interval [Q dn,cov , Q up,cov ]. Through automatic switching of the reactive power limit interval based on the control mode switching threshold, dynamic setting of the reactive power control limit is achieved.

[0084] Step 172: If the active power is lower than or equal to the control mode switching threshold, it is determined that the target reactive power control limit interval for the current substation is the second target reactive power control limit interval.

[0085] The formula for finally determining the reactive power control limit interval [Q dn , Q up ] is as follows (unit: MVar):

[0086]

[0087]

[0088] Figure 4 is a flowchart of the adjustment method of the substation reactive power control limit provided by another exemplary embodiment of the present application. As Figure 4 shown, step 140 can include:

[0089] Step 141: According to the substation topology operating mode, adjustable reactive power margin calculation is performed to obtain the adjustable reactive power margin, wherein the substation topology operating mode represents the connection mode of incoming lines, buses, transformers, capacitors, reactors, loads, and outgoing lines in the current substation.

[0090] The substation topology operating mode mainly refers to the main wiring type of the substation, including the connection mode of incoming lines, buses, transformers, capacitors, reactors, loads, and outgoing lines. Typical substation topology operating modes are as follows: Figure 2 The adjustable reactive power margin of the substation is mainly based on the topology operating mode, and is generally calculated based on the capacity of the capacitors and reactors connected to the low-voltage side of the transformer. The specific evaluation and calculation method is as follows:

[0091] First, the number of capacitors and reactors in the substation is counted and arranged in descending order according to the absolute value of the capacity to form a queue. Then, the state of each capacitor and reactor is evaluated according to the queue order. When there is a cold standby, abnormal telemetry value, abnormal switch remote signaling value, maintenance sign, etc. of the capacitor and reactor, the device is excluded from the queue. Finally, the absolute value of the capacity recorded in the first queue after the evaluation is completed as the adjustable reactive power margin Q regul (unit: Mvar, megavolt-ampere).

[0092] In an embodiment, step 141 can be specifically implemented as: arranging the capacitors and reactors in the current substation in descending order according to the absolute value of the capacity to obtain an arrangement sequence; sequentially evaluating the state of each capacitor and each reactor in the arrangement sequence according to the arrangement sequence to obtain an evaluation result; deleting abnormal capacitors and abnormal reactors in the arrangement sequence according to the evaluation result to obtain a target arrangement sequence; and selecting the absolute value of the capacity corresponding to the first column in the target arrangement sequence as the adjustable reactive power margin.

[0093] In an embodiment, step 110 can be specifically implemented as: obtaining an operation curve of a substation; dividing the operation curve into multiple time periods by peak, valley, flat peak, uphill, and downhill to obtain a peak time period, a valley time period, a flat peak time period, an uphill time period, and a downhill time period; setting a power factor upper limit value and a power factor lower limit value for each time period according to the start time and end time of each time period; and setting the power factor limit value interval according to the multiple power factor upper limit values and the multiple power factor lower limit values.

[0094] In an embodiment, the power factor upper limit value is cosf max , and the power factor lower limit value is cosf min , wherein step 110 can be specifically implemented as: setting a power factor upper limit value and a power factor lower limit value for each time period according to the start time and end time of each time period; and wherein the setting range of the power factor upper limit value and the power factor lower limit value is:

[0095] 0<cosf min <1;

[0096] 0<cosf max ≤1;

[0097] The setting of the power factor limit value interval according to the multiple power factor upper limit values and the multiple power factor lower limit values includes:

[0098] The power factor limit value interval is set according to the plurality of power factor upper limit values and the plurality of power factor lower limit values; wherein the power factor limit value interval is denoted as [cosf min ,cosf max ].

[0099] In an embodiment, P is the current substation active power, [Q dn,nom ,Q up,nom ] is the reactive power limit interval, Q up,nom is the upper limit of reactive power, and Q dn,nom is the lower limit of reactive power, and the unit is megavolt-ampere, and step 120 can be specifically implemented as:

[0100]

[0101]

[0102] In an embodiment, the control mode switching threshold P des , and the unit is megavolt-ampere, wherein step 160 can be specifically implemented as:

[0103]

[0104] Figure 5 is a structural schematic diagram of a substation reactive power control limit value adjustment device provided by another exemplary embodiment of the present application. As shown in Figure 5 , the substation reactive power control limit value adjustment device 20 comprises: an acquisition module 201 that acquires a power factor limit value interval and a reactive power limit conversion interval; a calculation module 202 that calculates a first reactive power limit interval according to a current substation active power and the power factor limit value interval; a determination module 203 that determines a coefficient value of the reactive power limit conversion interval according to a reactive power return principle; wherein the reactive power return principle indicates that the reactive power of the substation flows back to a high voltage level; an adjustable module 204 that performs adjustable reactive power margin calculation to obtain an adjustable reactive power margin according to a substation topology operation mode; an interval module 205 that calculates a second reactive power limit interval according to the reactive power limit conversion interval, the coefficient value, and the adjustable reactive power margin value; a threshold module 206 that calculates a control switching threshold according to a lower limit of reactive power in the second reactive power limit interval and a lower limit of power factor in the power factor limit value interval; and a condition module 207 that determines a target reactive power control limit value interval of the current substation reactive power control according to the first reactive power limit interval, the second reactive power limit interval, the control switching threshold, and a preset condition.

[0105] Figure 6 is a structural schematic diagram of a substation reactive power control limit value adjustment device provided by another exemplary embodiment of the present application. As shown in Figure 6 , the condition module 207 can comprise:

[0106] The first condition subunit 2071 is used to determine the target reactive power control limit range as the first target reactive power control limit range when the active power is greater than the control mode switching threshold; the second condition subunit 2072 is used to determine the target reactive power control limit range as the second target reactive power control limit range when the active power is less than or equal to the control mode switching threshold.

[0107] In one embodiment, such as Figure 6 As shown, the adjustable module 204 may include: an adjustable subunit 2041, used to perform adjustable reactive power margin calculation according to the substation topology operation mode, so as to obtain the adjustable reactive power margin. The substation topology operation mode refers to the connection mode of the incoming lines, busbars, transformers, capacitors, reactors, loads and outgoing lines in the current substation.

[0108] In one embodiment, such as Figure 6 As shown, the adjustable subunit 2041 can be specifically configured as follows: capacitors and reactors in the current substation are arranged in descending order according to their absolute capacity values ​​to obtain an arrangement sequence; each capacitor and each controller in the arrangement sequence is evaluated in turn according to the arrangement sequence to obtain an evaluation result; abnormal capacitors and abnormal reactors in the arrangement sequence are deleted based on the evaluation result to obtain a target arrangement sequence; and the absolute capacity value corresponding to the first column in the target arrangement sequence is selected as the adjustable reactive power margin.

[0109] In one embodiment, the determining module 203 may be specifically configured as follows: if the reactive power of the current substation flows back to the high voltage level, the determining coefficient value is a first threshold; if the current substation prohibits the reactive power from flowing back to the high voltage level, the determining coefficient value is a second threshold.

[0110] In one embodiment, the acquisition module 201 may be specifically configured to: acquire the operating curve of the substation; divide the operating curve into multiple time periods based on peak, valley, off-peak, uphill, and downhill periods to obtain peak period, valley period, off-peak period, uphill period, and downhill period; set upper and lower power factor values ​​for the peak period, valley period, off-peak period, uphill period, and downhill period respectively according to the start and end times of each time period; and set the power factor limit range according to the multiple upper and lower power factor values.

[0111] In one embodiment, the upper limit of the power factor is cosf max power factor lower limit cosf minwherein, according to the start time and the end time of each time period, the obtaining module 201 can be specifically configured to: according to the start time and the end time of each time period, set the power factor upper limit value and the power factor lower limit value for the peak time period, the valley time period, the flat peak time period, the uphill time period and the downhill time period respectively; wherein, the setting range of the power factor upper limit value and the power factor lower limit value is:

[0112] 0<cosf min <1;

[0113] 0<cosf max ≤1;

[0114] According to the plurality of power factor upper limit values and the plurality of power factor lower limit values, the power factor limit value interval is set; wherein, the power factor limit value interval is denoted as [cosf min ,cosf max ].

[0115] In an embodiment, P is the current substation active power, [Q dn,nom ,Q up,nom ] is the reactive power limit interval, Q up,nom is the upper limit of reactive power, Q dn,nom is the lower limit of reactive power, and the unit is megavolt-ampere, wherein, according to the current substation active power and the power factor limit value interval, the calculation module 202 can be specifically configured to:

[0116]

[0117]

[0118] In an embodiment, the control mode switching threshold P des , the unit is megawatt, wherein, according to the lower limit of reactive power in the second reactive power limit interval and the lower limit of power factor in the power factor limit value interval, the threshold module 206 can be specifically configured to:

[0119]

[0120] The 110kV substation low-voltage side bus is connected with 4 groups of controllable capacitors, and the capacity is 3.6, 3.6, 4.8, 4.8 (unit: MVar) respectively. The power factor limit value curve is set to [0.95, 1] according to 0:00-24:00 all day. According to the operation requirements of the local power dispatching department, the reactive power conversion interval is set to: the maximum conversion percentage is 0.8, and the minimum conversion percentage is 0.2, wherein the minimum conversion reactive power is allowed to be sent to the high voltage level.

[0121] According to the substation operation mode, the adjustable reactive power margin Qregul cosf min = 0.95, cosf max = 1, and according to the setting requirement of the reactive power conversion interval, we can get:

[0122] γ max = 0.8, γ min = 0.2, K1 = -1, K2 = 1.

[0123] According to the reactive power limit conversion interval [K1 x γ min , K2 x γ max ], the first reactive power limit interval [Q dn,cov , Q up,cov ] is calculated.

[0124] The calculation formula of the reactive power limit interval [Q dn,cov , Q up,cov ] is as follows:

[0125] Q up,cov = Q regul x K2 x γ max

[0126] Q dn,cov = Q regul x K1 x γ min

[0127] In the formula, Q up,cov is the upper limit of reactive power, Q up,cov is the lower limit of reactive power, and the unit is MVar.

[0128] The value of the reactive power limit interval [Q dn,cov , Q up,cov ] calculated by the above formula is (unit: MVar):

[0129] Q up,cov = 4.8 x 1 x 0.8 = 3.84

[0130] Q dn,cov = 4.8 x (-1) x 0.2 = -0.96

[0131] The control mode switching threshold P des (unit: MW) is calculated by the formula:

[0132]

[0133]

[0134]

[0135] ​At a certain moment, the substation active power is 20.17MW, according to the setting method, the power factor method is adopted, and the target reactive power limit interval at this moment is (unit MVar):

[0136]

[0137]

[0138] After that, with the sharp increase of new energy output, the substation active power is only 6.54, according to the setting method, the second reactive power limit interval at this moment is [Q dn,cov ,Q up,cov ](unit MVar), that is:

[0139] Q up,cov =3.84

[0140] Q dn,cov =-0.96

[0141] Through the adaptive adjustment of the target reactive power limit interval, the problem of narrow reactive power limit and reactive power control lockout when the active power is low according to the power factor calculation is solved, and the operation control effect of the substation is improved.

[0142] Next, an electronic device according to embodiments of the present application will be described with reference to Figure 7 . The electronic device can be either or both of the first and second devices, or a standalone device independent of them, which can communicate with the first and second devices to receive the input signals collected therefrom.

[0143] Figure 7 A block diagram of an electronic device according to embodiments of the present application is illustrated.

[0144] As shown in Figure 7 , the electronic device 10 includes one or more processors 11 and a memory 12.

[0145] The processor 11 can be a central processing unit (CPU) or other form of processing unit having data processing and / or instruction execution capabilities, and can control other components in the electronic device 10 to perform desired functions.

[0146] The memory 12 can include one or more computer program products that can include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory, for example, can include random access memory (RAM), cache memory, and / or the like. The non-volatile memory, for example, can include read only memory (ROM), hard disk, flash memory, and / or the like. One or more computer program instructions can be stored on the computer-readable storage media, which can be run by the processor 11 to implement the method of adjusting the reactive power control limit of a substation of various embodiments of the present application described above and / or other desired functions. Various contents such as input signals, signal components, noise components, and the like can also be stored in the computer-readable storage media.

[0147] In one example, the electronic device 10 can further include an input device 13 and an output device 14, which are interconnected through a bus system and / or other forms of connection mechanisms (not shown).

[0148] For example, when the electronic device is a stand-alone device, the input device 13 can be a communication network connector for receiving the acquired input signals from the first device and the second device.

[0149] In addition, the input device 13 can further include, for example, a keyboard, a mouse, and the like.

[0150] The output device 14 can output various information including the determined distance information, direction information, and the like to the outside. The output device 14 can include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto, and the like.

[0151] Of course, in order to simplify, Figure 7 Only some of the components in the electronic device 10 related to the present application are shown in the figure, and components such as buses, input / output interfaces, and the like are omitted. In addition, the electronic device 10 can further include any other appropriate components according to specific application cases.

[0152] In addition to the above-described method and device, an embodiment of the present application can be a computer program product including computer program instructions that, when executed by a processor, cause the processor to perform the steps of the control method of low-frequency load shedding based on a power grid according to various embodiments of the present application described in the above "Exemplary Methods" section of the specification.

[0153] The computer program product can be written in any combination of one or more programming languages, including an object oriented programming language such as Java, C++, or the like, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computing device, partly on the user's computing device, as a stand-alone software package, partly on the user's computing device and partly on a remote computing device or entirely on the remote computing device or server. The embodiments of the present application are not limited by the programming languages used to implement the methods.

[0154] In addition, the embodiments of the present application can also be a computer readable storage medium, which stores computer program instructions, and the computer program instructions, when executed by a processor, cause the processor to perform the steps in the control method of low-frequency load shedding based on power grid according to various embodiments of the present application described in the above “Exemplary Method” section of the specification.

[0155] The computer readable storage medium can take the form of one or more combinations of any type of computer readable medium. The computer readable medium can be a computer readable signal medium or a computer readable storage medium. The computer readable storage medium can include, for example, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or apparatus, or any suitable combination of the above. More specific examples (a non-exhaustive list) of the computer readable storage medium include an electrical connection having one or more wires, a portable disc, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0156] The basic principles of the present application are described above in combination with specific embodiments, but it should be pointed out that the advantages, advantages, effects, etc. mentioned in the present application are only examples and are not limited, and these advantages, advantages, effects, etc. cannot be considered as the must-have of each embodiment of the present application. In addition, the above-mentioned specific details are only for the purpose of example and for the purpose of understanding, and the above-mentioned details do not limit the present application to be necessarily implemented with the above-mentioned specific details.

[0157] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0158] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0159] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0160] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for adjusting reactive power control limits in a substation, characterized in that, include: Obtain the power factor limit range and the reactive power limit conversion range; Based on the current active power of the substation and the power factor limit range, a first reactive power limit range is calculated; based on the reactive power backflow principle, the coefficient value of the reactive power limit conversion range is determined; wherein, the reactive power backflow principle means that the reactive power of the substation flows back to the higher voltage level; based on the substation topology operation mode, an adjustable reactive power margin is calculated to obtain an adjustable reactive power margin; based on the reactive power limit conversion range, the coefficient value, and the adjustable reactive power margin value, a second reactive power limit range is calculated; based on the lower reactive power limit in the second reactive power limit range and the lower power factor limit in the power factor limit range, a control switching threshold is calculated; and based on the first reactive power limit range, the second reactive power limit range, the control switching threshold, and preset conditions, a target reactive power control limit range for the current substation reactive power control is determined; The step of determining the target reactive power control limit range for the current substation reactive power control based on the first reactive power limit range, the second reactive power limit range, the control switching threshold, and preset conditions includes: If the active power is greater than the control switching threshold, then the target reactive power control limit range for the current substation reactive power control is determined as the first target reactive power control limit range. If the active power is lower than or equal to the control switching threshold, then the target reactive power control limit range for the current substation reactive power control is determined as the second target reactive power control limit range. The power factor limit range includes: Obtain the operating curves of the substation; The operating curve is divided into multiple time periods based on peak, trough, off-peak, uphill, and downhill to obtain peak time periods, trough time periods, off-peak time periods, uphill time periods, and downhill time periods; Based on the start and end times of each time period, upper and lower power factor values ​​are set for the peak period, the trough period, the off-peak period, the uphill period, and the downhill period, respectively. The power factor limit range is set based on a plurality of upper power factor values ​​and a plurality of lower power factor values.

2. The method for adjusting the reactive power control limit of a substation according to claim 1, characterized in that, The process of calculating adjustable reactive power margin based on the substation topology operation mode to obtain the adjustable reactive power margin includes: Adjustable reactive power margin is calculated based on the substation topology operation mode to obtain the adjustable reactive power margin; wherein, the substation topology operation mode refers to the connection mode of the incoming lines, busbars, transformers, capacitors, reactors, loads and outgoing lines in the current substation.

3. The method for adjusting the reactive power control limit of a substation according to claim 2, characterized in that, The process of calculating adjustable reactive power margin based on the substation topology operation mode to obtain the adjustable reactive power margin includes: The capacitors and reactors in the current substation are arranged in descending order according to their absolute capacity to obtain the arrangement sequence; The state of each capacitor and each electronic controller in the arrangement sequence is evaluated sequentially to obtain the evaluation results; Based on the evaluation results, abnormal capacitors and abnormal reactors in the permutation sequence are removed to obtain the target permutation sequence; The absolute value of the capacity corresponding to the first column in the target permutation sequence is selected as the adjustable reactive power margin.

4. The method for adjusting the reactive power control limit of a substation according to claim 1, characterized in that, Based on the principle of reactive power backfeed, the coefficient values ​​for determining the reactive power limit conversion interval include: If the reactive power of the current substation flows back to the high voltage level, then the coefficient value is determined to be the first threshold. If the current substation prohibits reactive power from flowing back to higher voltage levels, then the coefficient value is determined to be the second threshold.

5. The method for adjusting the reactive power control limit of a substation according to claim 1, characterized in that, The upper limit of the power factor is cosf. max power factor lower limit cosf min The step of setting upper and lower power factor values ​​for the peak period, the trough period, the off-peak period, the uphill period, and the downhill period based on the start and end times of each period includes: Based on the start and end times of each time period, upper and lower power factor values ​​are set for the peak period, the trough period, the off-peak period, the uphill period, and the downhill period, respectively; wherein the range for setting the upper and lower power factor values ​​is as follows: 0<cosf min <1; 0<cosf max ≤1; The step of setting the power factor limit range based on the plurality of upper power factor values ​​and the plurality of lower power factor values ​​includes: Based on a plurality of upper power factor values ​​and a plurality of lower power factor values, a power factor limit range is defined; wherein, the power factor limit range is denoted as [cosf]. min cosf max ].

6. The method for adjusting the reactive power control limit of a substation according to claim 5, characterized in that, P represents the current active power of the substation, [Q] dn，nom Q up，nom [Q] represents the reactive power limit range. up,nom Q is the upper limit of reactive power. dn,nom The lower limit for reactive power is expressed in megavars. The formula for calculating the first reactive power limit range, based on the current active power of the substation and the power factor limit range, is as follows:

7. The method for adjusting the reactive power control limit of a substation according to claim 6, characterized in that, Control switching threshold P des The unit is megawatts, wherein the calculation formula for calculating the control switching threshold based on the lower limit of reactive power in the second reactive power limit range and the lower limit of power factor in the power factor limit range is as follows:

8. A device for adjusting reactive power control limits in a substation, applicable to the method for adjusting reactive power control limits in a substation as described in any one of claims 1-7, characterized in that, include: The acquisition module obtains the power factor limit range and the reactive power limit conversion range; The calculation module calculates the first reactive power limit range based on the current active power of the substation and the power factor limit range; The determining module determines the coefficient value of the reactive power limit conversion interval based on the reactive power backflow principle; wherein, the reactive power backflow principle means that the reactive power of the substation flows back to the higher voltage level; the adjustable module performs adjustable reactive power margin calculation based on the substation topology operation mode to obtain the adjustable reactive power margin. The interval module calculates the second reactive power limit interval based on the reactive power limit conversion interval, the coefficient value, and the adjustable reactive power margin value; the threshold module calculates the control switching threshold based on the lower reactive power limit in the second reactive power limit interval and the lower power factor limit in the power factor limit interval; the condition module determines the target reactive power control limit interval for the current substation reactive power control based on the first reactive power limit interval, the second reactive power limit interval, the control switching threshold, and preset conditions.

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