Method for controlling reactive voltage of new energy pooling station

Abstract

The invention provides a new energy pooling station reactive voltage control method, and belongs to the technical field of power grid automatic voltage control. The method comprises the following steps that: an AVC (Automatic Voltage Control) master station performs voltage static security domain calculation according to a set master station control period 1 and issues a new energy pooling station AVC sub-station, and performs new energy pooling station control instruction calculation according to a set master station control period 2 and issues the new energy pooling station control instruction to the new energy pooling station AVC sub-station; and the new energy pooling station AVC sub-station performs control according to a set sub-station control period based on the calculation result issued by the AVC main station. According to the method, the control period of the AVC substation of the new energy pooling station can be prolonged to 1 minute, the autonomy of voltage regulation of the AVC substation is enhanced, and the AVC substation is matched with the AVC main station and the SVG device to form a full-time-dimension coordination control system of main station optimization control, substation rapid control and SVG device emergency control.

Description

Technical Field

[0001] The invention belongs to the technical field of automatic voltage control of power grids, and in particular relates to a method for controlling reactive voltage of a new energy collection station. Background Art

[0002] The new energy collection station is connected to a large number of new energy sites (mainly wind farms and photovoltaic power stations). Although it is a substation, it is very close to the new energy sites, and new energy power generation is intermittent and volatile, resulting in bus voltage fluctuations at the new energy collection station that are more frequent and violent than those of ordinary substations.

[0003] The current power system generally installs an automatic voltage control system AVC (Automatic Voltage Control) in the power grid control center to monitor the voltage state of the power grid in real time, perform state estimation and power flow calculation, and generate control instructions. For ordinary substations, the AVC system of the dispatching master station will generate control instructions for capacitors and transformers. For ordinary substations equipped with SVG (static var generator) equipment, it will also generate SVG control instructions; for power plants (including new energy stations), AVC substations are usually configured in the station. The AVC system of the dispatching master station sends control instructions to the AVC substation, and the AVC substation controls the generators and other adjustable reactive equipment in the power plant. Since the AVC substation of the power plant generally controls continuously adjustable equipment such as generators or SVG, it generally takes the bus voltage on the high-voltage side of the main transformer as the control target, and performs continuous adjustment to meet the requirements of the dispatching master station. The technology of the AVC substation of the power plant is already quite mature. For the control of ordinary substations, the AVC system of the dispatching master station will first consider whether the bus voltage in the station meets the requirements. If the bus voltage exceeds the limit or reactive power is reversed, a control strategy to eliminate the bus voltage exceeding the limit or reactive power is generated; when the bus voltage and reactive power in the station are within a reasonable range, the optimization control instructions are generated according to the results of global optimization. Since the AVC system of the dispatching master station needs to control most of the stations in the system, considering the communication delay and response speed of each station, the control cycle of the AVC master station is generally 5 minutes, that is, a round of control instructions is generated and issued every 5 minutes.

[0004] As a special type of substation, some new energy collection stations are equipped with AVC substations, while others are designed according to ordinary substations without AVC substations. Since the substation AVC substation needs to control discrete reactive devices such as capacitors and taps, and also needs to control continuously adjustable reactive devices such as SVG, and the voltage fluctuation of new energy collection stations is large, there is still room for further improvement in this aspect. For new energy collection stations without AVC substations, they passively receive instructions from the dispatching master station to respond. Even for new energy collection stations equipped with AVC substations, they receive instructions from the AVC master station every 5 minutes and perform control. They are not proactive and cannot effectively suppress the frequent voltage fluctuations caused by new energy. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology and propose a control method for reactive voltage of a new energy collection station. The present invention can increase the control period of the AVC substation of the new energy collection station to 1 minute, while enhancing the autonomy of the AVC substation in regulating voltage, and cooperate with the AVC master station and the SVG device to form a full-time dimension coordinated control system of "master station optimization control, substation rapid control, and SVG device emergency control".

[0006] The embodiment of the present invention provides a method for controlling reactive voltage of a new energy collection station, including:

[0007] 1) The AVC master station calculates the voltage static safety domain with the set master station control cycle 1 and issues it to the AVC substation of the new energy collection station, and calculates the control instructions of the new energy collection station with the set master station control cycle 2 and issues it to the AVC substation of the new energy collection station; wherein the control instructions include: reactive power control instructions on the low-voltage side of the main transformer and SVG equipment control instructions, and the master station control cycle 1 is greater than the master station control cycle 2;

[0008] 2) The AVC substation of the new energy collection station is controlled according to the calculation results sent by the AVC master station with a set substation control cycle; wherein the substation control cycle is less than the master station control cycle 2.

[0009] In a specific embodiment of the present invention, the master station control period 1 is 15 minutes, the master station control period 2 is 5 minutes, and the substation control period is 1 minute.

[0010] In a specific embodiment of the present invention, it also includes:

[0011] 1-1) When the master station control cycle 1 arrives, the AVC master station predicts the voltage change trend of the future renewable energy collection area based on the change in active power generation trend, and considers the voltage change after the site in the renewable energy area is disconnected from the grid or the expected N-1 fault, calculates the voltage static safety domain of the renewable energy area and sends it to the renewable energy collection station AVC substation;

[0012] Among them, the static safety domain of the high-voltage bus voltage of the new energy collection station i is (Ulexam i ,Uhexam i ), Ulexam i The voltage safety operating lower limit of the new energy collection station i, Uhexam i It is the upper limit of voltage safety operation of new energy collection station i;

[0013] 1-2) When the master station control cycle 2 arrives, the AVC master station adjusts the bus voltage of the new energy collection station and considers whether the bus voltage of the new energy collection station exceeds the limit:

[0014] If the bus voltage of the new energy collection station exceeds the limit, a strategy to eliminate the bus voltage exceeding the limit is generated and sent to the AVC substation of the new energy collection station;

[0015] If the bus voltage of the new energy collection station does not exceed the limit, an optimization control strategy or a leveling strategy is generated and sent to the AVC substation of the new energy collection station; when the difference between the optimization value and the actual value of the bus voltage on the high-voltage side of the main transformer is outside the optimization dead zone, the optimization control strategy is executed, that is, the main transformer low-voltage side reactive power increment control instruction or the SVG equipment reactive power increment control instruction is sent to the AVC substation of the new energy collection station; when the difference between the optimization value and the actual value of the bus voltage on the high-voltage side of the main transformer is within the optimization dead zone, the main transformer low-voltage side reactive power leveling control instruction and the SVG equipment reactive power leveling control instruction are sent to the AVC substation of the new energy collection station;

[0016] 1-3) When the master station control cycle 2 arrives, the AVC master station collects the increaseable and decreaseable reactive power on the low-voltage side of the main transformer calculated by the AVC substation of the new energy collection station, and collects the increaseable and decreaseable reactive power sent by the SVG at the same time;

[0017] For any main transformer k, the AVC substation can increase reactive power by 1TrQInc0 k , can increase reactive power 2TrQInc1 k , can reduce reactive power 1TrQDec0 k , can reduce reactive power 2TrQDec1 k ;

[0018] 1-4) When the master station control cycle 2 arrives, the AVC master station calculates the control instructions of the new energy collection station and sends them to the AVC substation of the new energy collection station;

[0019] Among them, for the main transformer k, the reactive power control instruction TrQSet on the low-voltage side of the main transformer is calculated k ; For on-load tap-changing transformers, the tap control instruction TrTap is also calculated k ;

[0020] For SVG device m, calculate and obtain the reactive power setting instruction SVGQSet of the SVG device m .

[0021] In a specific embodiment of the present invention, it also includes:

[0022] 1-5) When the master station control cycle 2 arrives, the AVC master station gathers the total active power transmission plan data of the new energy collection station according to the active power generation plan and forecast data of the lower-level new energy stations in the future period of the new energy collection station, and according to the trend change of the total active power transmission plan, the discrete reactive equipment is adjusted first when the new energy transmission is climbing or declining, and the SVG reactive power is adjusted first in the other stable or fluctuating periods of new energy transmission; at the same time, the AVC master station fully considers the requirements of dynamic reactive power reserve of SVG equipment in the new energy collection station, generates reactive power replacement strategy and sends it to AVC substation.

[0023] In a specific embodiment of the present invention, it also includes:

[0024] 2-1) For the new energy collection station i, the new energy collection station AVC substation receives the main transformer high voltage side bus voltage static safety domain (Ulexam i ,Uhexam i ), denoted as A1; the operating limit of the bus voltage on the high-voltage side of the local main transformer of the AVC substation is denoted as A2; the intersection of A1 and A2 is obtained to obtain A3, A3=A1∩A2, A3 is denoted as (UlRun i ,UhRun i ), UlRun i is the lower limit of the bus voltage operation on the high-voltage side of the main transformer of the new energy collection station i, UhRun i The upper limit of the bus voltage operation on the high-voltage side of the main transformer at the new energy collection station i;

[0025] 2-2) When the substation control cycle arrives, the new energy collection station AVC substation generates a control unit according to the real-time topology in the station; if it is detected that the bus voltage on the three sides of the main transformer in the control unit exceeds the limit, then go to step 2-3); otherwise, go to step 2-4);

[0026] 2-3) When the bus voltage on the three sides of the main transformer in the control unit exceeds the limit, a strategy to eliminate the bus voltage exceeding the limit is generated;

[0027] If the bus voltages on two or three sides of the three sides exceed the limit at the same time, the order of eliminating the bus voltage exceeding the limit is determined according to the set bus voltage assessment type priority;

[0028] 2-4) When the bus voltages on the three sides of the main transformer in the control unit are not out of limit, the AVC substation performs corresponding control according to the current control mode, which includes a remote control mode and a local control mode;

[0029] The remote control mode includes: the AVC master station sends instructions to the AVC substation of the new energy collection station according to the master station control cycle 2, and the AVC substation is controlled according to the instructions sent by the AVC master station;

[0030] When the communication between the new energy collection station and the AVC master station is interrupted, the new energy collection station AVC substation is greater than or equal to the set disconnection time threshold TCut max When no instruction is received from the AVC master station within a continuous period of time, it switches to local control mode; afterwards, when the AVC substation of the new energy collection station receives an instruction from the AVC master station again, it switches to remote control mode, and the AVC substation is controlled according to the instruction issued by the AVC master station.

[0031] In a specific embodiment of the present invention, it also includes:

[0032] The mth SVG device receives the reactive power setting instruction SVGQSet issued by the AVC substation m And the static safety domain limit value Ulexam of the bus voltage on the high-voltage side of the main transformer i and Uhexam i After that, when the SVG device detects the bus voltage U h In (Ulexam i ,Uhexam i ) range, it executes the SVGQSet issued by the AVC substation in the constant reactive power control mode. m Reactive power setting command; when U h Not in (Ulexam i ,Uhexam i ) range, the SVG device automatically and quickly acts to quickly support low voltage or suppress high voltage, and controls the bus voltage on the high voltage side of the main transformer to (Ulexam i ,Uhexam i ) range.

[0033] In a specific embodiment of the present invention, it also includes:

[0034] When the AVC substation of the new energy collection station detects that the bus voltage on the three sides of the main transformer in the control unit is out of limit, and at the same time detects that the AVC master station has issued a new control instruction, the AVC substation mainly controls based on the locally generated strategy to eliminate the bus voltage over-limit, and temporarily abandons the control instruction issued by the master station.

[0035] In a specific embodiment of the present invention, it also includes:

[0036] When the bus voltage exceeds the limit in the control unit j, the AVC substation of the new energy collection station coordinates the automatic control of the reactor and SVG equipment in the control unit in the following way:

[0037] 2-3-1) Let n SVGs be controllable in control unit j;

[0038] For the xth SVG device, set its adjustable capacity upper limit to SVGQmax x , the lower limit of adjustable capacity is SVGQmin x , the upper limit of steady-state voltage regulation reactive power is SVGstmax x , the lower limit of steady-state voltage regulation reactive power is SVGstmin x , the current reactive power is SVGQ x ;

[0039] If the bus voltage exceeds the lower limit, reactive power needs to be increased; for the xth device among the n controllable SVG devices, if SVGQ x <SVGstmin x or SVGQ x +Qdead x <SVGstmax x , then the SVG device is selected to participate in the adjustment, where Qdead x is the reactive power regulation dead zone of SVG device x;

[0040] If the bus voltage exceeds the upper limit, the reactive power needs to be reduced; for the xth device among the n controllable SVG devices, if SVGQ x >SVGstmax x or SVGQ x -Qdead x >SVGstmin x , then the SVG device is selected to participate in the adjustment;

[0041] 2-3-2) After the screening in step 2-3-1), p SVG devices are selected from n SVG devices to participate in the adjustment;

[0042] For the xth SVG device among the p SVG devices, its reactive preset value is SVGQSet x , SVGQSetx =SVGQ x +ΔSVGQ x , ΔSVGQ x is the budget adjustment amount for the xth SVG;

[0043] If reactive power is added, calculate SVGQLeft x =SVGQmax x -SVGQSet x ; If reactive power is reduced, calculate SVGQLeft x =SVGQSet x -SVGQmin x , SVGQLeft x The reactive remaining adjustable capacity of the xth SVG device;

[0044] 2-3-3) Based on the result of step 2-3-2), select SVGQLeft in p SVG devices x The largest SVG device performs adjustments, and the remaining SVGs issue horizontal adjustment instructions;

[0045] If n is 0 or p is 0, the capacitor in the control unit j is selected to be switched on and off to eliminate the voltage exceeding the limit.

[0046] In a specific embodiment of the present invention, it also includes:

[0047] The process of determining whether the n controllable SVG devices in the control unit j implement the reactive power replacement strategy is as follows:

[0048] 2-4-1) Calculate the replaceable reactive power of each SVG device;

[0049] Among them, the replaceable reactive power of the xth SVG device is SVGQS x ;

[0050] If SVGstmin x ≤SVGQ x ≤SVGstmax x , then SVGQS x =0; if SVGQ x <SVGstmin x , then SVGQS x =SVGstmin x -SVGQ x ; If SVGQ x >SVGstmax x , then SVGQS x =SVGstmax x -SVGQ x ;

[0051] 2-4-2) Based on the result of step 2-4-1), calculate the total replaceable reactive power

[0052] 2-4-3) Let the reactive power replacement threshold be Qs, and determine:

[0053] If |SVGQS|>Qs, the reactive power replacement strategy between the SVG device and the capacitive reactor is executed; if |SVGQS|<=Qs, the reactive power replacement strategy between each SVG device is executed.

[0054] Features and beneficial effects of the present invention:

[0055] 1) The present invention can realize the configuration of AVC substations in the new energy collection station to actively detect voltage exceeding the limit, thereby enhancing the autonomy of reactive voltage regulation in the new energy collection station. Even if the communication between the new energy collection station and the main station is interrupted, the new energy collection station can still complete the task of autonomous voltage regulation, control the voltage in the station at a reasonable level, and reduce the pressure of manual voltage regulation. At the same time, compared with the previous control strategy of the AVC substation of the new energy collection station, there will be a 15-minute "zero regulation" period during the local control process when the communication between the AVC substation and the main station is interrupted, that is, during these 15 minutes, the AVC substation only waits for instructions from the main station and cannot generate any strategy autonomously. After adopting the new control strategy, the AVC substation can detect whether the bus voltage of the new energy collection station exceeds the limit at all times and make adjustments.

[0056] 2) The present invention adopts a 1-minute period of rapid coordinated control, which enhances the agility of the AVC substation voltage regulation and the timeliness of the response, can suppress voltage fluctuations more quickly, prevent the voltage from exceeding the limit for a long time, and reduce the probability of the wind turbine or inverter in the new energy station area in the new energy collection station area being disconnected from the grid due to voltage exceeding the limit.

[0057] 3) Through the above measures, the reactive voltage regulation level of the new energy collection station can be improved, thereby stabilizing the voltage level of the entire new energy collection area, indirectly increasing the number of hours of new energy utilization and promoting the consumption of new energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is an overall flow chart of a method for controlling reactive voltage of a new energy collection station according to an embodiment of the present invention. DETAILED DESCRIPTION

[0059] The present invention proposes a method for controlling reactive voltage in a new energy collection station, which is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0060] The embodiment of the present invention provides a method for controlling reactive voltage of a new energy collection station, including:

[0061] 1) The AVC master station calculates the voltage static safety domain with the set master station control cycle 1 and issues it to the AVC substation of the new energy collection station, and calculates the control instructions of the new energy collection station with the set master station control cycle 2 and issues it to the AVC substation of the new energy collection station; wherein the control instructions include: reactive power control instructions on the low-voltage side of the main transformer and SVG equipment control instructions, and the master station control cycle 1 is greater than the master station control cycle 2;

[0062] 2) The AVC substation of the new energy collection station is controlled according to the calculation results sent by the AVC master station with a set substation control cycle; wherein the substation control cycle is less than the master station control cycle 2.

[0063] In a specific embodiment of the present invention, the control method of reactive voltage of a new energy collection station is as follows: Figure 1 As shown, the following steps are included:

[0064] 1) The AVC master station calculates the voltage static safety domain with the set master station control cycle 1 and issues it to the AVC substation of the new energy collection station, and calculates the control instructions of the new energy collection station with the set master station control cycle 2 and issues it to the AVC substation of the new energy collection station; wherein the control instructions include: reactive power control instructions on the low-voltage side of the main transformer and SVG equipment control instructions;

[0065] In this embodiment, the master station control cycle 1 is usually greater than or equal to 15 minutes, and in a specific embodiment of the present invention, it is 15 minutes; the master station control cycle 1 is greater than the master station control cycle 2; in a specific implementation of the present invention, the master station control cycle 2 is usually 5 minutes. Specifically including:

[0066] 1-1) When the master station control cycle 1 arrives (15 minutes in this embodiment), the AVC master station considers the changes in the active power generation trend of the new energy collection area in the future, and predicts the voltage change trend of the new energy collection area in the future based on the changes in the active power generation trend. On the other hand, it considers the voltage changes after the site in the new energy area is disconnected from the grid or the expected N-1 fault, calculates the voltage static safety domain of the new energy area and sends it to the new energy collection station AVC substation.

[0067] In this embodiment, for the new energy collection station i, the static safety domain of the high-voltage side bus voltage of the station can be calculated as (Ulexam i ,Uhexam i ), of which Ulexam i The voltage safety operating lower limit of the new energy collection station i, Uhexam i It is the upper limit of voltage safety operation of renewable energy collection station i. The AVC master station sends the static safety domain of high-voltage bus voltage of renewable energy collection station i to the AVC substation of renewable energy collection station in each control cycle.

[0068] 1-2) When the master station control cycle 2 arrives (5 minutes in this embodiment), the AVC master station considers whether the bus voltage of the new energy collection station exceeds the limit when adjusting the bus voltage of the new energy collection station:

[0069] If the bus voltage of the new energy collection station exceeds the limit, a strategy to eliminate the bus voltage exceeding the limit is generated and sent to the AVC substation of the new energy collection station;

[0070] If the bus voltage of the new energy collection station does not exceed the limit, an optimization control strategy or a leveling strategy is generated and sent to the AVC substation of the new energy collection station. Among them, the optimization control strategy will take into account the future active power generation plan and forecast data as well as the results of the optimal power flow calculation, so as to obtain the optimized value of the bus voltage on the high-voltage side of the main transformer. When the difference between the optimized value and the actual value of the bus voltage on the high-voltage side of the main transformer is outside the optimization dead zone range, the optimization control strategy is executed, that is, the main transformer low-voltage side reactive power increment control instruction or the SVG equipment reactive power increment control instruction is sent to the AVC substation of the new energy collection station; when the difference between the optimized value and the actual value of the bus voltage on the high-voltage side of the main transformer is within the optimization dead zone range, the main transformer low-voltage side reactive power leveling control instruction and the SVG equipment reactive power leveling control instruction are sent to the AVC substation of the new energy collection station.

[0071] In this embodiment, the reactive power control instruction generally adopts a 4-bit coding format, the thousands digit is the reactive power adjustment direction, 1 indicates reactive power reduction, 2 indicates reactive power increase; the hundreds digit is a cyclic code, which cycles between 1 and 5; the tens digit and the ones digit are reactive power adjustment amounts. For example, 1X30 indicates reactive power reduction of 30Mvar, while 1X00 indicates a level adjustment instruction.

[0072] 1-3) When the master station control cycle 2 arrives (5 minutes in this embodiment), the AVC master station collects the increaseable and decreaseable reactive power on the low-voltage side of the main transformer calculated by the new energy collection station AVC substation, and at the same time collects the increaseable and decreaseable reactive power sent by the SVG.

[0073] In this embodiment, for the main transformer k, the AVC substation sends TrQInc0 k (can increase reactive power 1), TrQInc1 k (can increase reactive power 2), TrQDec0 k (can reduce reactive power 1), TrQDec1 k (Can reduce reactive power 2).

[0074] 1-4) When the master station control cycle 2 arrives (5 minutes in this embodiment), the AVC master station calculates the new energy collection station control instructions, including control instructions based on the main transformer and control instructions based on the SVG, and sends them to the new energy collection station AVC substation.

[0075] Among them, for the main transformer k, the reactive power control instruction TrQSet on the low-voltage side of the main transformer is calculated k ; For on-load tap-changing transformers, there can also be a tap control instruction TrTap k For SVG device m, the reactive power setting instruction SVGQSet of the SVG device can be calculated. m .

[0076] Further,

[0077] 1-5) When the master station control cycle 2 arrives (5 minutes in this embodiment), the AVC master station gathers the total active power transmission plan data of the new energy collection station based on the active power generation plan and forecast data of the lower-level new energy stations in the future period of the new energy collection station, and according to the trend change of the total active power transmission plan, the discrete reactive equipment is adjusted first when the new energy transmission is climbing (trough-peak conversion period) or descending (peak-trough conversion period), and the SVG reactive power is adjusted first in the other stable or fluctuating periods of new energy transmission. At the same time, the AVC master station fully considers the requirements of dynamic reactive power reserve of SVG equipment in the new energy collection station, generates reactive power replacement strategy and sends it to the AVC substation.

[0078] 2) The AVC substation of the new energy collection station is controlled according to the set substation control cycle based on the calculation results sent by the AVC master station.

[0079] In this embodiment, the substation control period is less than the master station control period 2; in a specific implementation of the present invention, the substation control period is 1 minute. Specifically including:

[0080] 2-1) For the new energy collection station i, the new energy collection station AVC substation receives the main transformer high voltage side bus voltage static safety domain (Ulexam i ,Uhexam i ), denoted as A1; the operating limit of the bus voltage on the high-voltage side of the local main transformer of the AVC substation is denoted as A2; the intersection of A1 and A2 is obtained to obtain A3, A3=A1∩A2, A3 is denoted as (UlRun i ,UhRun i ), UlRun i is the lower limit of the bus voltage operation on the high-voltage side of the main transformer of the new energy collection station i, UhRun i is the upper limit of the bus voltage operation on the high-voltage side of the main transformer of the new energy collection station i. In this way, the operating limit of the bus voltage on the high-voltage side of the main transformer of the new energy collection station can be flexibly and real-time adjusted according to the requirements of the master station.

[0081] In this embodiment, the bus voltage operating limits on the medium voltage side and the low voltage side of the main transformer still use the locally input limits, and are adjusted every quarter (monthly) according to relevant dispatching regulations.

[0082] 2-2) When the substation control cycle arrives, the AVC substation of the new energy collection station generates a control unit according to the real-time topology in the station. If it is detected that the bus voltage on the three sides of the main transformer in the control unit exceeds the limit, then go to step 2-3); otherwise, go to step 2-4).

[0083] In this embodiment, the bus voltage over-limit of the new energy collection station is mainly eliminated autonomously by the AVC substation through 1 minute of rapid control.

[0084] 2-3) When the bus voltage on the three sides of the main transformer in the control unit exceeds the limit, a strategy to eliminate the bus voltage exceeding the limit is generated.

[0085] In this embodiment, if the bus voltage on two sides or three sides of the three sides exceeds the limit at the same time, the order of eliminating the bus voltage exceeding the limit is determined according to the set bus voltage assessment type priority. The AVC substation of the new energy collection station generally eliminates the voltage exceeding the limit by switching on and off the reactor equipment in the control station or adjusting the SVG equipment. For the on-load tap-changing transformer, the transformer tap can also be adjusted, but the tap is generally not automatically controlled, but a relevant prompt alarm is given to manually perform the up and down gear operation of the transformer tap.

[0086] In this embodiment, when the bus voltage exceeds the limit in the control unit j, the AVC substation of the new energy collection station coordinates the automatic control of the reactor and the SVG device in the control unit in the following manner:

[0087] 2-3-1) Let n SVGs be controllable in control unit j. For the xth SVG device, let its adjustable capacity upper limit be SVGQmax x , the lower limit of adjustable capacity is SVGQmin x , the upper limit of steady-state voltage regulation reactive power is SVGstmax x , the lower limit of steady-state voltage regulation reactive power is SVGstmin x , the current reactive power is SVGQ x If the bus voltage exceeds the lower limit, reactive power needs to be increased. Among them, for the xth device among the n controllable SVG devices, if SVGQ x <SVGstmin x or SVGQ x +Qdead x <SVGstmax x , then the SVG device is selected to participate in the adjustment, where Qdead x The reactive power regulation deadband of SVG device x.

[0088] If the bus voltage exceeds the upper limit, reactive power needs to be reduced. For the xth device among the n controllable SVG devices, if SVGQ x >SVGstmax xor SVGQ x -Qdead x >SVGstmin x , the SVG device is selected to participate in the adjustment.

[0089] 2-3-2) After the screening in step 2-3-1), p SVG devices are selected from n SVG devices to participate in the adjustment. Then, for the xth SVG device among the p SVG devices, its reactive power preset value is SVGQSet x , SVGQSet x =SVGQ x +ΔSVGQ x , ΔSVGQ x is the budget adjustment of the xth SVG. If reactive power is added, SVGQLeft is calculated x =SVGQmax x -SVGQSet x ; If reactive power is reduced, calculate SVGQLeft x =SVGQSet x -SVGQmin x , SVGQLeft x Reactive remaining adjustable capacity of the xth SVG device.

[0090] 2-3-3) Based on the result of step 2-3-2), select SVGQLeft in p SVG devices x The largest SVG device performs adjustments, and the remaining SVGs issue horizontal adjustment instructions.

[0091] If n is 0 or p is 0, and no SVG device can be used to eliminate the voltage over-limit, the capacitor in the control unit j is selected to eliminate the voltage over-limit. The switching of the capacitor must fully consider the voltage over-limit estimation after switching, the distance from the over-limit bus, the series resistance compensation degree of the capacitor, the bus balance, the number of capacitor actions, whether it refuses to operate, and other factors, and select which capacitor device to switch according to the calculation factor (the specific method can refer to patent CN102055192A).

[0092] Furthermore, after the AVC substation of the new energy collection station selects the capacitor device to be switched on and off, it follows the minimum duration CPT after the capacitor is switched on or off min , as well as the control unit's same-direction and reverse reactive power regulation lockout time limit to prevent repeated and frequent adjustment of the capacitor and over-regulation of the reactive voltage.

[0093] In this embodiment, for the SVG device, since the AVC substation control cycle is increased to 1 minute and the SVG device is continuously adjustable, a smaller reactive power regulation step SVGQStep can be set in each round; when adjusting the SVG device individually, restrictions such as the same-direction and reverse reactive power regulation lockout time of the control unit can be ignored, and the "small step, multiple rounds" strategy can be used to continuously adjust the SVG device to achieve better regulation effects.

[0094] 2-4) When the bus voltages on the three sides of the main transformer in the control unit are not beyond the limit, the AVC substation performs corresponding control according to the current control mode. The control mode includes remote control mode and local control mode.

[0095] Among them, the remote control mode includes: the AVC master station sends instructions to the new energy collection station AVC substation according to the master station control cycle 2 (every 5 minutes in this embodiment), and the AVC substation is controlled according to the instructions sent by the AVC master station.

[0096] In extreme cases, when the communication between the new energy collection station and the AVC master station is interrupted, the new energy collection station AVC substation is greater than or equal to the set disconnection time threshold TCut max When no instruction is received from the AVC master station within a continuous period of time (usually 15 minutes), it switches to local control mode. After that, when the AVC substation of the new energy collection station receives an instruction from the AVC master station again, it switches to remote control mode, and the AVC substation controls according to the instruction issued by the AVC master station.

[0097] In this embodiment, the low-voltage side reactive power control instruction TrQSet received by the AVC substation from the main transformer k k After parsing, if it is a non-leveling instruction, after verification, the corresponding capacitor under the main transformer k is selected for switching control; for the reactive setting instruction SVGQSet received by the AVC substation from the SVG device m m , after passing the capacity verification of m, it is sent to SVG device m, and at the same time forwards the static safety domain limit value Ulexam of the bus voltage on the high-voltage side of the main transformer to the SVG device i and Uhexam i .

[0098] Furthermore, for the mth SVG device, it receives the reactive power setting instruction SVGQSet sent by the AVC substation. m And the static safety domain limit value Ulexam of the bus voltage on the high-voltage side of the main transformer i and Uhexam i When the SVG device detects the main transformer high voltage side bus voltage U h In (Ulexam i ,Uhexam i) range, it executes the SVGQSet issued by the AVC substation in the constant reactive power control mode. m Reactive power setting command; when U h Not in (Ulexam i ,Uhexam i ) range, the SVG device automatically and quickly acts (<30ms) to quickly support low voltage or suppress high voltage, and control the bus voltage on the high voltage side of the main transformer to (Ulexam i ,Uhexam i ) range.

[0099] It should be noted that when the AVC substation of the new energy collection station detects that the bus voltage on the three sides of the main transformer in the control unit is out of limit, and at the same time detects that the AVC main station has issued a new control instruction, the AVC substation will mainly control based on the locally generated strategy to eliminate the bus voltage over-limit, and temporarily abandon the control instruction issued by the main station.

[0100] Furthermore, in this embodiment, when the bus voltage of the new energy collection station is within the normal range and the AVC substation is in the local control mode, if the SVG device meets the reactive power replacement threshold, the AVC substation executes the reactive power replacement strategy of the SVG device and the capacitor.

[0101] In this embodiment, the process of determining whether the n controllable SVG devices in the control unit j execute the reactive power replacement strategy is as follows:

[0102] 2-4-1) Calculate the replaceable reactive power of each SVG device to check whether its reactive power meets the requirements of dynamic reactive power reserve.

[0103] Among them, the replaceable reactive power of the xth SVG device is SVGQS x ;

[0104] If SVGstmin x ≤SVGQ x ≤SVGstmax x , then SVGQS x =0; if SVGQ x <SVGstmin x , then SVGQS x =SVGstmin x -SVGQ x ; If SVGQ x >SVGstmax x , then SVGQS x =SVGstmax x -SVGQ x .

[0105] 2-4-2) Based on the result of step 2-4-1), the replaceable reactive power of n controllable SVG devices is accumulated to obtain the total replaceable reactive power

[0106] 2-4-3) Let the reactive power replacement threshold be Qs, and determine:

[0107] If |SVGQS|>Qs, the reactive power replacement strategy between the SVG device and the capacitive reactor is executed; if |SVGQS|<=Qs, the reactive power replacement strategy between each SVG device is executed.

Claims

1. A method for controlling reactive voltage of a new energy collection station, characterized in that: include: 1) The AVC master station calculates the voltage static safety domain with the set master station control cycle 1 and issues it to the AVC substation of the new energy collection station, and calculates the control instructions of the new energy collection station with the set master station control cycle 2 and issues it to the AVC substation of the new energy collection station; wherein the control instructions include: reactive power control instructions on the low-voltage side of the main transformer and SVG equipment control instructions, and the master station control cycle 1 is greater than the master station control cycle 2; 2) The AVC substation of the new energy collection station is controlled according to the calculation results sent by the AVC master station with a set substation control cycle; wherein the substation control cycle is less than the master station control cycle 2.

2. The method according to claim 1, characterized in that The master station control cycle 1 is 15 minutes, the master station control cycle 2 is 5 minutes, and the substation control cycle is 1 minute.

3. The method according to claim 1, characterized in that Also includes: 1-1) When the master station control cycle 1 arrives, the AVC master station predicts the voltage change trend of the future renewable energy collection area based on the change in active power generation trend, and considers the voltage change after the site in the renewable energy area is disconnected from the grid or the expected N-1 fault, calculates the voltage static safety domain of the renewable energy area and sends it to the renewable energy collection station AVC substation; Among them, the static safety domain of the high-voltage bus voltage of the new energy collection station i is (Ulexam i ,Uhexam i ), Ulexam i The voltage safety operating lower limit of the new energy collection station i, Uhexam i It is the upper limit of voltage safety operation of new energy collection station i; 1-2) When the master station control cycle 2 arrives, the AVC master station adjusts the bus voltage of the new energy collection station and considers whether the bus voltage of the new energy collection station exceeds the limit: If the bus voltage of the new energy collection station exceeds the limit, a strategy to eliminate the bus voltage exceeding the limit is generated and sent to the AVC substation of the new energy collection station; If the bus voltage of the new energy collection station does not exceed the limit, an optimization control strategy or a leveling strategy is generated and sent to the AVC substation of the new energy collection station; when the difference between the optimization value and the actual value of the bus voltage on the high-voltage side of the main transformer is outside the optimization dead zone, the optimization control strategy is executed, that is, the main transformer low-voltage side reactive power increment control instruction or the SVG equipment reactive power increment control instruction is sent to the AVC substation of the new energy collection station; when the difference between the optimization value and the actual value of the bus voltage on the high-voltage side of the main transformer is within the optimization dead zone, the main transformer low-voltage side reactive power leveling control instruction and the SVG equipment reactive power leveling control instruction are sent to the AVC substation of the new energy collection station; 1-3) When the master station control cycle 2 arrives, the AVC master station collects the increaseable and decreaseable reactive power on the low-voltage side of the main transformer calculated by the AVC substation of the new energy collection station, and collects the increaseable and decreaseable reactive power sent by the SVG at the same time; For any main transformer k, the AVC substation can increase reactive power by 1TrQInc0 k , can increase reactive power 2TrQInc1 k , can reduce reactive power 1TrQDec0 k , can reduce reactive power 2TrQDec1 k ; 1-4) When the master station control cycle 2 arrives, the AVC master station calculates the control instructions of the new energy collection station and sends them to the AVC substation of the new energy collection station; Among them, for the main transformer k, the reactive power control instruction TrQSet on the low-voltage side of the main transformer is calculated k ; For on-load tap-changing transformers, the tap control instruction TrTap is also calculated k ; For SVG device m, calculate and obtain the reactive power setting instruction SVGQSet of the SVG device m .

4. The method according to claim 3, characterized in that Also includes: 1-5) When the master station control cycle 2 arrives, the AVC master station gathers the total active power transmission plan data of the new energy collection station according to the active power generation plan and forecast data of the lower-level new energy stations in the future period of the new energy collection station, and according to the trend change of the total active power transmission plan, the discrete reactive equipment is adjusted first when the new energy transmission is climbing or declining, and the SVG reactive power is adjusted first in the other stable or fluctuating periods of new energy transmission; at the same time, the AVC master station fully considers the requirements of dynamic reactive power reserve of SVG equipment in the new energy collection station, generates reactive power replacement strategy and sends it to AVC substation.

5. The method according to claim 4, characterized in that Also includes: 2-1) For the new energy collection station i, the new energy collection station AVC substation receives the main transformer high voltage side bus voltage static safety domain (Ulexam i ,Uhexam i ), denoted as A1; the operating limit of the bus voltage on the high-voltage side of the local main transformer of the AVC substation is denoted as A2; the intersection of A1 and A2 is obtained to obtain A3, A3=A1∩A2, A3 is denoted as (UlRun i ,UhRun i ), UlRun i is the lower limit of the bus voltage operation on the high-voltage side of the main transformer of the new energy collection station i, UhRun i The upper limit of the bus voltage operation on the high-voltage side of the main transformer at the new energy collection station i; 2-2) When the substation control cycle arrives, the new energy collection station AVC substation generates a control unit according to the real-time topology in the station; if it is detected that the bus voltage on the three sides of the main transformer in the control unit exceeds the limit, then go to step 2-3); otherwise, go to step 2-4); 2-3) When the bus voltage on the three sides of the main transformer in the control unit exceeds the limit, a strategy to eliminate the bus voltage exceeding the limit is generated; If the bus voltages on two or three sides of the three sides exceed the limit at the same time, the order of eliminating the bus voltage exceeding the limit is determined according to the set bus voltage assessment type priority; 2-4) When the bus voltages on the three sides of the main transformer in the control unit are not out of limit, the AVC substation performs corresponding control according to the current control mode, which includes a remote control mode and a local control mode; The remote control mode includes: the AVC master station sends instructions to the AVC substation of the new energy collection station according to the master station control cycle 2, and the AVC substation is controlled according to the instructions sent by the AVC master station; When the communication between the new energy collection station and the AVC master station is interrupted, the new energy collection station AVC substation is greater than or equal to the set disconnection time threshold TCut max When no instruction is received from the AVC master station within a continuous period of time, it switches to local control mode; afterwards, when the AVC substation of the new energy collection station receives an instruction from the AVC master station again, it switches to remote control mode, and the AVC substation is controlled according to the instruction issued by the AVC master station.

6. The method according to claim 5, characterized in that Also includes: The mth SVG device receives the reactive power setting instruction SVGQSet issued by the AVC substation m And the static safety domain limit value Ulexam of the bus voltage on the high-voltage side of the main transformer i and Uhexam i After that, when the SVG device detects the main transformer high voltage side bus voltage U h In (Ulexam i ,Uhexam i ) range, it executes the SVGQSet issued by the AVC substation in the constant reactive power control mode. m Reactive power setting command; when U h Not in (Ulexam i ,Uhexam i ) range, the SVG device automatically and quickly acts to quickly support low voltage or suppress high voltage, and controls the bus voltage on the high voltage side of the main transformer to (Ulexam i ,Uhexam i ) range.

7. The method according to claim 5, characterized in that Also includes: When the AVC substation of the new energy collection station detects that the bus voltage on the three sides of the main transformer in the control unit is out of limit, and at the same time detects that the AVC master station has issued a new control instruction, the AVC substation mainly controls based on the locally generated strategy to eliminate the bus voltage over-limit, and temporarily abandons the control instruction issued by the master station.

8. The method according to claim 5, characterized in that Also includes: When the bus voltage exceeds the limit in the control unit j, the AVC substation of the new energy collection station coordinates the automatic control of the reactor and SVG equipment in the control unit in the following way: 2-3-1) Let n SVGs be controllable in control unit j; For the xth SVG device, set its adjustable capacity upper limit to SVGQmax x , the lower limit of adjustable capacity is SVGQmin x , the upper limit of steady-state voltage regulation reactive power is SVGstmax x , the lower limit of steady-state voltage regulation reactive power is SVGstmin x , the current reactive power is SVGQ x ; If the bus voltage exceeds the lower limit, reactive power needs to be increased; for the xth device among the n controllable SVG devices, if SVGQ x <SVGstmin x or SVGQ x +Qdead x <SVGstmax x , then the SVG device is selected to participate in the adjustment, where Qdead x is the reactive power regulation dead zone of SVG device x; If the bus voltage exceeds the upper limit, reactive power needs to be reduced; for the xth device among the n controllable SVG devices, if SVGQ x >SVGstmax x or SVGQ x -Qdead x >SVGstmin x , then the SVG device is selected to participate in the adjustment; 2-3-2) After the screening in step 2-3-1), p SVG devices are selected from n SVG devices to participate in the adjustment; For the xth SVG device among the p SVG devices, its reactive preset value is SVGQSet x , SVGQSet x =SVGQ x +ΔSVGQ x , ΔSVGQ x is the budget adjustment amount for the xth SVG; If reactive power is added, calculate SVGQLeft x =SVGQmax x -SVGQSet x ; If reactive power is reduced, calculate SVGQLeft x =SVGQSet x -SVGQmin x , SVGQLeft x The reactive remaining adjustable capacity of the xth SVG device; 2-3-3) Based on the result of step 2-3-2), select SVGQLeft in p SVG devices x The largest SVG device performs adjustments, and the remaining SVGs issue horizontal adjustment instructions; If n is 0 or p is 0, the capacitor in the control unit j is selected to be switched on and off to eliminate the voltage exceeding the limit.

9. The method according to claim 5, characterized in that Also includes: The process of determining whether the n controllable SVG devices in the control unit j implement the reactive power replacement strategy is as follows: 2-4-1) Calculate the replaceable reactive power of each SVG device; Among them, the replaceable reactive power of the xth SVG device is SVGQS x ; If SVGstmin x ≤SVGQ x ≤SVGstmax x , then SVGQS x =0; if SVGQ x <SVGstmin x , then SVGQS x =SVGstmin x -SVGQ x ; If SVGQ x >SVGstmax x , then SVGQS x =SVGstmax x -SVGQ x ; 2-4-2) Based on the result of step 2-4-1), calculate the total replaceable reactive power 2-4-3) Let the reactive power replacement threshold be Qs, and determine: If |SVGQS|>Qs, the reactive power replacement strategy between the SVG device and the capacitive reactor is executed; if |SVGQS|<=Qs, the reactive power replacement strategy between each SVG device is executed.

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