Photovoltaic AVC substation time-division control method and device considering assessment rules

Abstract

The invention provides a photovoltaic AVC substation time-phased control method and device considering an assessment rule, and relates to the technical field of power grid automatic voltage control. The method comprises the following steps: determining a current control time period of a photovoltaic AVC substation according to a received command moment of a power grid regulation and control center AVC master station and an assessment rule; and determining the current control mode of the photovoltaic AVC substation according to the current control time period of the photovoltaic AVC substation, and performing adjustment control according to the current control mode of the photovoltaic AVC substation. Thus, different control modes are adapted in different time periods according to the assessment rules, the requirement of the station for voltage safety is met, the requirement of the dispatching master station for reactive voltage regulation of the new energy station can be met, the effect of the station for autonomously optimizing voltage regulation can be fully played, the three modes promote each other, the safety margin of the station voltage is improved, and the safety of the station voltage is improved. And meanwhile, the assessment cost is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of automatic voltage control of power grids, and in particular to a time-sharing control method and device for a photovoltaic AVC substation taking into account assessment rules. Background Art

[0002] New energy power stations are power stations that use renewable energy or pollution-free energy to generate electricity. Their purpose is to replace traditional fossil energy power generation and reduce environmental pollution and global warming. Solar photovoltaic power stations use solar energy as energy and convert it into electricity through photovoltaic panels to generate electricity. With the proposal of my country's dual carbon goals, by 2030, carbon dioxide emissions will be controlled at the peak and efforts will be made to reach the peak as soon as possible. By 2060, various means will be used to offset carbon dioxide emissions with carbon dioxide absorbed by technical means such as afforestation and carbon capture, achieving net zero emissions. In order to achieve this goal, a new round of photovoltaic power station construction is in full swing. Due to its own characteristics, photovoltaic power stations have intermittent and volatile power generation, which leads to unstable voltage of photovoltaic power stations. In order to ensure the stability of the station voltage, AVC (Automatic Voltage Control) substations are generally installed in photovoltaic power stations. They receive instructions issued by the AVC master station system of the power grid control center, and then regulate the reactive equipment in the station so that the voltage / reactive power of the grid connection point meets the requirements of the grid.

[0003] The AVC master station of the power grid control center periodically generates control instructions and sends them to the AVC substation of the photovoltaic power station. The cycle is generally no more than 5 minutes. In order to better constrain the substation to adjust the voltage and reactive power according to the instructions of the master station, the master station AVC system will evaluate and assess the regulation effect of the AVC substation of the photovoltaic power station.

[0004] At present, most of the AVC substations of photovoltaic power stations use the mode of following the control instructions of the main station to adjust the voltage of the station. Although the ideas of emergency control and optimization control have been proposed, in order to better meet the requirements of the control instructions of the main station and avoid the generation of assessment costs, emergency control and optimization control have not fully played their role, so that various control modes hinder each other and cannot form a joint force to achieve a higher level of reactive voltage regulation. Therefore, this technical problem needs to be solved urgently. Summary of the invention

[0005] In view of the above problems, this application is proposed to provide a photovoltaic AVC substation time-sharing control method and device taking into account the assessment rules to overcome the above problems or at least partially solve the above problems. Different control modes are adapted in different time periods according to the assessment rules, which can not only meet the needs of the station's own voltage safety, but also meet the requirements of the dispatching master station for reactive voltage regulation of the new energy station, and at the same time give full play to the role of the station's autonomous optimization of voltage regulation, so that the three can promote each other, improve the safety margin of the station voltage, and avoid the generation of assessment costs. The technical solution is as follows:

[0006] In a first aspect, a time-sharing control method for a photovoltaic AVC substation taking into account assessment rules is provided, including:

[0007] According to the command time and assessment rules received from the AVC master station of the power grid control center, the current control time period of the photovoltaic AVC substation is determined;

[0008] According to the control time period of the photovoltaic AVC substation, the control mode of the photovoltaic AVC substation is determined, and the photovoltaic AVC substation is adjusted and controlled according to the control mode of the photovoltaic AVC substation.

[0009] In a second aspect, a photovoltaic AVC substation time-sharing control device taking into account assessment rules is provided, including:

[0010] A determination unit, used to determine the current control time period of the photovoltaic AVC substation according to the command time received from the AVC master station of the power grid control center and the assessment rules;

[0011] The control unit is used to determine the current control mode of the photovoltaic AVC substation according to the current control time period of the photovoltaic AVC substation, and perform adjustment and control according to the current control mode of the photovoltaic AVC substation.

[0012] By means of the above technical scheme, the embodiment of the present application provides a photovoltaic AVC substation time-division control method and device taking into account the assessment rules. The method determines the current control time period of the photovoltaic AVC substation according to the time of receiving the instruction from the AVC master station of the power grid control center and the assessment rules; determines the current control mode of the photovoltaic AVC substation according to the current control time period of the photovoltaic AVC substation, and adjusts and controls according to the current control mode of the photovoltaic AVC substation. In this way, different control modes are adapted in different time periods according to the assessment rules, which not only meets the needs of the station's own voltage safety, but also meets the requirements of the dispatching master station for reactive voltage regulation of the new energy station, and at the same time can give full play to the role of the station's autonomous optimization of voltage regulation, so that the three promote each other, improve the safety margin of the station voltage, and avoid the generation of assessment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in describing the embodiments of the present application are briefly introduced below.

[0014] Figure 1 A flow chart of a photovoltaic AVC substation time-division control method taking into account assessment rules provided in an embodiment of the present application is shown;

[0015] Figure 2 A schematic diagram of a control time period provided in an embodiment of the present application is shown;

[0016] Figure 3a A flowchart of a photovoltaic AVC substation time-division control method taking into account assessment rules provided in another embodiment of the present application is shown;

[0017] Figure 3b A schematic diagram showing a combination of a control time period and a control mode according to an embodiment of the present application is shown;

[0018] Figure 4 A structural diagram of a photovoltaic AVC substation time-sharing control device taking into account assessment rules provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0019] The exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0020] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that such use is interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the term "including" and its variants are to be interpreted as open-ended terms meaning "including but not limited to".

[0021] In order to solve the above technical problems, the embodiment of the present application provides a photovoltaic AVC substation time-sharing control method taking into account the assessment rules, such as Figure 1 As shown, the photovoltaic AVC substation time-division control method taking into account the assessment rules may include the following steps S101 and S102:

[0022] Step S101, according to the received command time of the AVC master station of the power grid control center and the assessment rules, determine the control time period in which the photovoltaic AVC substation is currently located.

[0023] In this step, the assessment rules can be set according to actual needs, and this embodiment does not limit this.

[0024] For example, suppose the instruction issuing cycle of the AVC master station is T c , see Figure 2 As shown in the figure, the time when the photovoltaic AVC substation receives the latest control instruction from the AVC master station is T0. According to the assessment rules, the photovoltaic AVC substation has T adj time to adjust, set T1 = T0 + T adj , then the photovoltaic AVC substation control time period from T0 to T1 is the adjustment time period; according to the assessment rules, the AVC master station will collect T exam The duration data is used for assessment and calculation, and T2 = T1 + T exam , then the photovoltaic AVC substation control time period from T1 to T2 is the assessment time period; let T afexam =T c -(T adj +T exam ), then from time T2 to T2+T afexam The time period is the time period after the assessment. If the next round of AVC master station instructions are issued at time T3, and T3<T2+T afexam , then the time period from T2 to T3 is the post-assessment time period. According to this method, the control period of the photovoltaic AVC substation is divided into three time periods: the adjustment time period, the assessment time period, and the post-assessment time period.

[0025] Step S102, determining the current control mode of the photovoltaic AVC substation according to the current control time period of the photovoltaic AVC substation, and performing adjustment and control according to the current control mode of the photovoltaic AVC substation.

[0026] In this step, the control mode of the photovoltaic AVC substation is generally divided into emergency control mode, correction control mode and optimization control mode. i , the voltage safety upper limit is U i sup, the voltage safety lower limit is U i sdn, B i The bus voltage value is U i real, when U i real>=U i sup or U i real<=U i sdn, the PV AVC substation enters the emergency control mode; for the inverter equipment G i , the voltage safety upper limit is UG i sup, its lower safety limit is UG i sdn, the terminal voltage of the inverter equipment is UGi real, count all UG i real>UG i The number of sup inverter devices is N gup , statistics of all UG i real <UG i The number of inverter devices in sdn is N gdn , assuming that the threshold number of the emergency control inverter of the photovoltaic AVC substation is N safe , when N gup >=N safe or N gdn >=N safe When the PV AVC substation enters the emergency control mode, the traditional PV AVC substation controls the dead zone U according to the voltage. dead and balance control dead zone U bal To determine whether the photovoltaic AVC substation is in the correction control mode or the optimization control mode. In this embodiment, the control time period of the AVC substation will be fully considered to finally determine the control mode of the AVC substation.

[0027] This embodiment adapts different control modes in different time periods according to the assessment rules, which not only meets the needs of the station's own voltage safety, but also meets the requirements of the dispatching master station for reactive voltage regulation of the new energy station, while giving full play to the station's autonomous optimization of voltage regulation, so that the three can promote each other, improve the safety margin of the station voltage, and avoid assessment costs.

[0028] A possible implementation method is provided in an embodiment of the present application, and the control time period mentioned above may include any time period of the adjustment time period, the assessment time period, and the post-assessment time period;

[0029] In step S101, according to the received command time of the AVC master station of the power grid control center and the assessment rules, the current control time period of the photovoltaic AVC substation is determined, which may specifically include the following steps A1 and A2:

[0030] Step A1: Assume that the instruction issuing period of the AVC master station is T c The time when the photovoltaic AVC substation receives the latest control instruction from the AVC master station is T0. According to the assessment rules, the photovoltaic AVC substation has T adj time to adjust, set T1 = T0 + T adj , then the photovoltaic AVC substation control time period from T0 to T1 is the adjustment time period; according to the assessment rules, the AVC master station will collect T exam The duration data is used for assessment and calculation, and T2 = T1 + T exam , then the photovoltaic AVC substation control time period from T1 to T2 is the assessment time period; let T afexam =Tc -(T adj +T exam ), then from time T2 to T2+T afexam The time period is the time period after the assessment. If the next round of AVC master station instructions are issued at time T3, and T3<T2+T afexam , then the time period from T2 to T3 is the post-assessment time period;

[0031] Step A2: determining the current control time period of the photovoltaic AVC substation according to the defined adjustment time period, assessment time period and post-assessment time period.

[0032] This embodiment can determine the current control time period of the photovoltaic AVC substation according to the assessment rules, so that different control modes can be adapted in different time periods.

[0033] A possible implementation method is provided in an embodiment of the present application, and the control mode mentioned above may include any control mode of an emergency control mode, a correction control mode, and an optimization control mode;

[0034] In step S102, according to the control time period in which the photovoltaic AVC substation is currently located, the control mode in which the photovoltaic AVC substation is currently located is determined, and adjustment and control are performed according to the control mode in which the photovoltaic AVC substation is currently located, which may specifically include the following steps B1:

[0035] Step B1, when the photovoltaic AVC substation is currently in the adjustment time period, determine the current control mode of the photovoltaic AVC substation. When the photovoltaic AVC substation is currently in the emergency control mode, if the photovoltaic AVC substation's own voltage regulation demand is opposite to the instruction issued by the dispatching AVC master station, then temporarily abandon the instruction issued by the dispatching AVC master station, and adjust the voltage of the bus or inverter equipment that exceeds the safety limit in the photovoltaic station to the normal range; when the photovoltaic AVC substation is not currently in the emergency control mode, set the voltage instruction issued by the dispatching AVC master station as U set , and the control voltage of the photovoltaic AVC substation is U real , the control dead zone of the photovoltaic AVC substation is U dead , when |U set -U real |>=U dead When |U set -U real |<U dead When the PV AVC substation does not perform optimization control, it enters the command leveling stage under the correction control mode, that is, it issues leveling commands to each reactive device.

[0036] In the embodiment of the present application, a possible implementation method is provided. In step S102, the current control mode of the photovoltaic AVC substation is determined according to the current control time period of the photovoltaic AVC substation, and the photovoltaic AVC substation is adjusted and controlled according to the current control mode of the photovoltaic AVC substation. Specifically, the following steps B2 may be included:

[0037] Step B2: when the PV AVC substation is currently in the assessment period, determine the current control mode of the PV AVC substation; when the PV AVC substation is currently in the emergency control mode, adjust according to the emergency control mode; when the PV AVC substation is not currently in the emergency control mode and |U set -U real |>=U dead When |U set -U real |<U dead When the power is turned off, a leveling command is issued to each reactive equipment.

[0038] In the embodiment of the present application, a possible implementation method is provided. In step S102, the current control mode of the photovoltaic AVC substation is determined according to the current control time period of the photovoltaic AVC substation, and the photovoltaic AVC substation is adjusted and controlled according to the current control mode of the photovoltaic AVC substation. Specifically, the following steps B3 may be included:

[0039] Step B3: when the PV AVC substation is currently in the post-assessment time period, determine the current control mode of the PV AVC substation; when the PV AVC substation is currently in the emergency control mode, adjust according to the emergency control mode; when the PV AVC substation is not currently in the emergency control mode, set the current upper limit of the operation of the PV AVC substation control busbar to U runup , the lower limit of operation is U rundn , and the control voltage of the photovoltaic AVC substation is U real , when U real <U runup -2*U dead AndU real >U rundn +2*U dead When the control voltage of the photovoltaic AVC substation is within the upper and lower limits of normal operation, it is considered that the photovoltaic AVC substation enters the optimization control mode and is controlled according to the optimization control mode to eliminate the reactive circulating current of the main transformer and optimize the reactive distribution in the station.

[0040] The embodiment of the present application provides a possible implementation method. When the photovoltaic AVC substation is adjusted and controlled according to the emergency control mode, the main transformer high-voltage side bus is more secure. At this time, it is determined whether the adjustment direction of the instruction sent by the dispatching master station AVC to the photovoltaic AVC substation is consistent with the bus adjustment direction for adjusting the main transformer high-voltage side bus back to the normal range. When the two are consistent, the instruction U sent by the master station AVC is still followed. set If the adjustment directions of the two are inconsistent, the command issued by the master station AVC is temporarily abandoned, and the main transformer high-voltage side bus voltage is adjusted to the normal range. If the high-voltage side bus voltage U real >=U sup , U sup is the voltage safety upper limit, then the target value of the PV AVC substation is adjusted to U sup -2×U dead , if at this time the high voltage side bus voltage U real <=U sdn , U sdn is the voltage safety lower limit, the target value of the photovoltaic AVC substation is adjusted to U sdn +2×U dead After the photovoltaic AVC substation determines the adjustment target value, it adjusts the reactive equipment in the station to achieve the target; when the bus voltage on the low-voltage side of the main transformer exceeds the safety limit, it is determined whether the instruction issued by the dispatching AVC master station is consistent with the adjustment direction of the photovoltaic AVC substation to adjust the low-voltage side bus of the main transformer to the normal range. If the two are consistent, the instruction U issued by the dispatching AVC master station is still followed. set If the two adjustment directions are inconsistent, the low-voltage bus B that exceeds the limit i , the voltage safety upper limit is U i sup, the voltage safety lower limit is U i sdn, bus voltage value is U i real, if U i real>=U i sup,U lset =U i sup-2×U i dead, U i dead is bus B i The control dead zone is converted to the high-voltage side U hset =U lset ×U real / U i real, where U hset Set the target estimate for the high voltage side voltage, U real is the bus voltage on the high-voltage side of the main transformer, if U hset >=U sup -2×U dead , Uhset =U sup -2×U dead , if U hset <=U sdn +2×U dead , U hset =U sdn +2×U dead , considering the maximum step size limit of voltage regulation, if U hset >=U real +U maxstep , U hset =U real +U maxstep , if U hset <=U real -U maxstep , U hset =U real -U maxstep , thereby calculating the control target value U of the photovoltaic AVC substation hset , when U i real<=U i sdn,U lset =U i sdn+2×U i dead, and convert it to the high-voltage side to get U hset =U lset ×U real / U i real, considering the upper limit of the bus voltage U on the high-voltage side of the main transformer sup And the voltage lower limit U sdn After the constraints of voltage regulation step length and voltage regulation step length, we can get U hset , PV AVC substation with U hset The reactive equipment in the station is regulated as the target; when the terminal voltage of a certain number of photovoltaic inverters exceeds the safety limit, in the same way, when the instruction issued by the dispatching AVC master station is consistent with the regulation direction for adjusting the terminal voltage of the photovoltaic inverter back to the normal range, the instruction of the dispatching AVC master station is used as the control target. When the two are inconsistent, the control instruction of the dispatching AVC master station is temporarily abandoned. The maximum voltage regulation step of the photovoltaic AVC substation is set to U maxstep , and adjust with the maximum adjustment step size. If the inverter voltage is to be increased, then U hset =U real +U maxstep , if the inverter voltage is lowered, then U hset =U real -U maxstep and through the upper limit of the bus voltage U on the high voltage side of the main transformer sup And the voltage lower limit U sdn After verification, the final U hset, PV AVC substation with U hset The purpose is to adjust the reactive equipment within the station.

[0041] The embodiment of the present application provides a possible implementation method. When the photovoltaic AVC substation is controlled according to the correction control mode, according to the scheduling AVC master station control instruction U set Adjustment is performed, and the reactive demand is obtained through sensitivity calculation. The reactive command value of each reactive device is calculated according to the inverter priority adjustment or equal margin adjustment algorithm, and the bus voltage of each voltage level in the booster station after adjustment by the photovoltaic AVC substation is estimated. Reactive control instructions are issued to devices such as inverters and ordinary SVG (Static VarGenerator), and voltage control instructions are issued to devices such as distributed phase-shifting machines and grid-type SVG.

[0042] A possible implementation method is provided in the embodiment of the present application. When the photovoltaic AVC substation is controlled according to the optimization control mode, it eliminates the reactive circulating current of the main transformer through reactive replacement, and balances the reactive distribution of each reactive device. During the adjustment process, since the optimization control mode is only carried out in the time period after the assessment, its adjustment step can be carried out according to the normal adjustment step of the photovoltaic AVC substation. At the same time, it is necessary to avoid large fluctuations in the high-voltage side bus voltage. Therefore, the final high-voltage side reactive injection calculated at this time should be 0. Reactive optimization can be divided into two steps. The first is to eliminate the reactive circulating current between the main transformers. For a station with multiple main transformers, the two main transformers with the largest circulating current can be selected for control. The circulating current of these two main transformers is eliminated first. In the next round, the two main transformers with the largest circulating current are found until the main transformer circulating current is eliminated; the second step is to balance the circulating current that may appear in the reactive equipment under each main transformer, and perform reactive replacement of fast reactive adjustment and slow reactive adjustment.

[0043] The embodiment of the present application provides a possible implementation method for determining the current control mode of the photovoltaic AVC substation, which specifically includes the following steps C1:

[0044] Step C1: For busbar equipment B in the booster station i , the voltage safety upper limit is U i sup, the voltage safety lower limit is U i sdn, B i The bus voltage value is U i real, when U i real>=U i sup or U i real<=U i sdn, the PV AVC substation enters the emergency control mode; for the inverter equipment G i , the voltage safety upper limit is UG isup, its lower safety limit is UG i sdn, the terminal voltage of the inverter equipment is UG i real, count all UG i real>UG i The number of sup inverter devices is N gup , statistics of all UG i real <UG i The number of inverter devices in sdn is N gdn , assuming that the threshold number of the emergency control inverter of the photovoltaic AVC substation is N safe , when N gup >=N safe or N gdn >=N safe When the PV AVC substation enters the emergency control mode.

[0045] In addition, the traditional photovoltaic AVC substation controls the dead zone U according to the voltage dead and balance control dead zone U bal To determine whether the photovoltaic AVC substation is in the correction control mode or the optimization control mode. In this embodiment, the control time period of the AVC substation will be fully considered to finally determine the control mode of the AVC substation.

[0046] The above introduces Figure 1 There are various implementation methods for each link of the illustrated embodiment. The photovoltaic AVC substation time-division control method taking into account the assessment rules of the embodiment of the present application will be further explained below through specific embodiments.

[0047] Figure 3a A flow chart of a photovoltaic AVC substation time-division control method taking into account assessment rules provided in another embodiment of the present application is shown.

[0048] exist Figure 3a In the process, the PV AVC substation determines the current control time period and whether it is an adjustment time period. If it is an adjustment time period, the PV AVC substation determines the current control mode (emergency control mode or correction control mode), and adjusts and controls according to the current control mode of the PV AVC substation, and continues to the next round of judgment.

[0049] If it is not an adjustment time period, determine whether it is an assessment time period. If it is an assessment time period, the photovoltaic AVC substation determines the current control mode (emergency control mode or correction control mode), and adjusts and controls according to the current control mode of the photovoltaic AVC substation, and continues to the next round of judgment.

[0050] If it is not the assessment time period, it is the post-assessment time period. The PV AVC substation determines the current control mode (emergency control mode or optimization control mode), and adjusts and controls according to the current control mode of the PV AVC substation, and continues to the next round of judgment. Here, different time periods are adapted to different control modes, such as Figure 3b shown.

[0051] exist Figure 3b The adjustment time period is adapted to the emergency control mode and the correction control mode; the assessment time period is adapted to the emergency control mode and the correction control mode; the post-assessment time period is adapted to the emergency control mode and the optimization control mode.

[0052] In a specific embodiment, a photovoltaic power station is provided with two main transformers with a rated capacity of 150MVA. The bus voltage level on the high-voltage side of the main transformer is 220KV, the upper limit of the voltage safety on the high-voltage side of the main transformer is 236KV, the lower limit of the voltage safety on the high-voltage side of the main transformer is 220KV, and the control dead zone is 0.5KV. The bus voltage level on the low-voltage side of the main transformer is 35kV, the upper limit of the voltage safety on the low-voltage side of the main transformer is 39KV, the lower limit of the voltage safety on the low-voltage side of the main transformer is 33KV, and the control dead zone is 0.2KV. There are 300 inverters, each with an installed capacity of 0.5MW, a rated terminal voltage of 0.315KV, a voltage safety upper limit of 0.340KV, and a voltage safety lower limit of 0.290KV. The control cycle of the photovoltaic AVC substation is 30 seconds.

[0053] The current high-voltage side bus voltage of the optical station power station is 230.0KV, and the adjustment command received from the master station AVC system is 229.0KV. The photovoltaic AVC substation enters the adjustment time period. The reactive power on the high-voltage side of #1 main transformer is -4Mvar, and the reactive power on the high-voltage side of #2 main transformer is 2Mvar. There is circulating current between #1 main transformer and #2 main transformer, resulting in inconsistent voltages on the two bus sections. The current voltage value of the 35KVI bus section is 35.5KV, and the current voltage value of the 35KVII bus section is 34.5KV. The terminal voltages of each inverter are around 0.31KV. The terminal voltages of some inverters under the 35KVII bus section are low, at around 0.3KV. At this time, the photovoltaic AVC substation enters the correction control mode after judgment, and adjusts the reactive equipment in the station to follow the command 229.0KV issued by the master station. After two rounds of adjustment, 1 minute later, the voltage on the high-voltage side of the station stabilized at 229.3KV. The photovoltaic AVC substation determines that the high-voltage side control bus voltage has entered the control dead zone, and then issues a leveling command to each reactive equipment in the station within a certain period of time.

[0054] 2 minutes later, the PV AVC substation entered the assessment period. At this time, the voltage on the high-voltage side of the station was about 229.3KV. The PV AVC substation continued to issue leveling instructions to the reactive equipment in the station. At this time, due to the sudden change in weather, the active output of the inverter dropped sharply, the reactive output also changed, and the voltage of some inverters changed. The PV AVC substation detected that the voltage of 11 inverters under the 35KVII bus was lower than the lower limit of 0.290KV, exceeding the PV AVC substation emergency control inverter threshold of 10. The PV AVC substation entered the emergency control mode. The AVC substation adjusted the reactive power of the SVG equipment in the station to increase the voltage on the high-voltage side of the main transformer to 230.0KV, and the voltage of the 11 inverters that exceeded the limit was also increased to about 0.305KV. In the next control cycle, the photovoltaic AVC substation detects that the bus voltages are within the safe upper and lower limits, and enters the correction control mode again to adjust the reactive power of each reactive device so that the high-voltage side bus voltage is adjusted to 229.20KV. After that, the photovoltaic AVC substation sends leveling instructions to each reactive device.

[0055] 4 minutes later, the assessment period ended, and the photovoltaic AVC substation entered the post-assessment period. It detected that the voltage of each busbar device was within the safe upper and lower limits, and entered the optimization control mode. By adjusting the output of each SVG device under the #1 main transformer and the #2 main transformer, the reactive power on the high-voltage side of the #1 main transformer was adjusted to -1Mvar, the reactive power on the high-voltage side of the #2 main transformer was adjusted to -1Mvar, the bus voltage of the 35KVI section was adjusted to 35.2KV, the bus voltage of the 35KVII section was adjusted to 35.0KV, and the voltage of some inverters with low voltage under the 35KVII section bus was also adjusted from 0.300KV to 0.305KV. After that, the photovoltaic AVC substation issued a leveling command to each reactive device. 5 minutes later, the photovoltaic AVC substation received a new control command issued by the dispatching AVC master station, entered a new round of adjustment period, and started a new round of control.

[0056] It should be noted that the size of the sequence number of each step in the above embodiment does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application. In practical applications, all the above possible implementation methods can be combined in any way to form possible embodiments of the present application, which will not be described one by one here.

[0057] Based on the photovoltaic AVC substation time-division control method taking into account the assessment rules provided in the above embodiments, based on the same inventive concept, the embodiment of the present application also provides a photovoltaic AVC substation time-division control device taking into account the assessment rules.

[0058] Figure 41 is a structural diagram of a photovoltaic AVC substation time-sharing control device taking into account the assessment rules provided in the embodiment of the present application. Figure 4 As shown, the photovoltaic AVC substation time-division control device taking into account the assessment rules may specifically include a determination unit 410 and a control unit 420.

[0059] The determination unit 410 is used to determine the control time period of the photovoltaic AVC substation according to the received instruction time of the AVC master station of the power grid control center and the assessment rules;

[0060] The control unit 420 is used to determine the current control mode of the photovoltaic AVC substation according to the current control time period of the photovoltaic AVC substation, and perform adjustment and control according to the current control mode of the photovoltaic AVC substation.

[0061] A possible implementation manner is provided in an embodiment of the present application, wherein the control time period includes any time period of an adjustment time period, an assessment time period, and a post-assessment time period; and the determining unit 410 is further configured to:

[0062] Assume that the instruction issuing cycle of the AVC master station is T c The time when the photovoltaic AVC substation receives the latest control instruction from the AVC master station is T0. According to the assessment rules, the photovoltaic AVC substation has T adj time to adjust, set T1 = T0 + T adj , then the photovoltaic AVC substation control time period from T0 to T1 is the adjustment time period; according to the assessment rules, the AVC master station will collect T exam The duration data is used for assessment and calculation, and T2 = T1 + T exam , then the photovoltaic AVC substation control time period from T1 to T2 is the assessment time period; let T afexam =T c -(T adj +T exam ), then from time T2 to T2+T afexam The time period is the time period after the assessment. If the next round of AVC master station instructions are issued at time T3, and T3<T2+T afexam , then the time period from T2 to T3 is the post-assessment time period;

[0063] According to the defined adjustment time period, assessment time period and post-assessment time period, the current control time period of the photovoltaic AVC substation is determined.

[0064] A possible implementation method is provided in an embodiment of the present application, wherein the control mode includes any one of an emergency control mode, a correction control mode, and an optimization control mode; the control unit 420 is further configured to:

[0065] When the photovoltaic AVC substation is currently in the adjustment time period, the current control mode of the photovoltaic AVC substation is determined. When the photovoltaic AVC substation is currently in the emergency control mode, if the photovoltaic AVC substation's own voltage regulation demand is opposite to the instruction issued by the dispatching AVC master station, the instruction issued by the dispatching AVC master station is temporarily abandoned, and the voltage of the bus or inverter equipment that exceeds the safety limit in the photovoltaic field station is adjusted to the normal range; when the photovoltaic AVC substation is not currently in the emergency control mode, the voltage instruction issued by the dispatching AVC master station is set to U set , and the control voltage of the photovoltaic AVC substation is U real , the control dead zone of the photovoltaic AVC substation is U dead , when |U set -U real |>=U dead When |U set -U real |<U dead When the PV AVC substation does not perform optimization control, it enters the command leveling stage under the correction control mode, that is, it issues leveling commands to each reactive device.

[0066] A possible implementation method is provided in an embodiment of the present application, wherein the control unit 420 is further configured to:

[0067] When the PV AVC substation is currently in the assessment period, determine the current control mode of the PV AVC substation. When the PV AVC substation is currently in the emergency control mode, adjust according to the emergency control mode. When the PV AVC substation is not currently in the emergency control mode and |U set -U real |>=U dead When |U set -U real |<U dead When the power is turned off, a leveling command is issued to each reactive equipment.

[0068] A possible implementation method is provided in an embodiment of the present application, wherein the control unit 420 is further configured to:

[0069] When the PV AVC substation is currently in the post-assessment time period, determine the current control mode of the PV AVC substation. When the PV AVC substation is currently in the emergency control mode, adjust according to the emergency control mode. When the PV AVC substation is not currently in the emergency control mode, set the current upper limit of the operation of the PV AVC substation control busbar to U runup, the lower limit of operation is U rundn , and the control voltage of the photovoltaic AVC substation is U real , when U real <U runup -2*U dead AndU real >U rundn +2*U dead When the control voltage of the photovoltaic AVC substation is within the upper and lower limits of normal operation, it is considered that the photovoltaic AVC substation enters the optimization control mode and is controlled according to the optimization control mode to eliminate the reactive circulating current of the main transformer and optimize the reactive distribution in the station.

[0070] A possible implementation method is provided in an embodiment of the present application, wherein the control unit 420 is further configured to:

[0071] When the PV AVC substation is adjusted and controlled according to the emergency control mode, the busbar on the high-voltage side of the main transformer exceeds the safety limit. At this time, it is determined whether the adjustment direction of the command issued by the dispatching master station AVC to the PV AVC substation is consistent with the busbar adjustment direction for adjusting the busbar on the high-voltage side of the main transformer back to the normal range. When the two are consistent, the command U issued by the master station AVC is still followed. set If the adjustment directions of the two are inconsistent, the command issued by the master station AVC is temporarily abandoned, and the main transformer high-voltage side bus voltage is adjusted to the normal range. If the high-voltage side bus voltage U real >=U sup , U sup is the voltage safety upper limit, then the target value of the PV AVC substation is adjusted to U sup -2×U dead , if at this time the high voltage side bus voltage U real <=U sdn , U sdn is the voltage safety lower limit, the target value of the photovoltaic AVC substation is adjusted to U sdn +2×U dead After the photovoltaic AVC substation determines the adjustment target value, it adjusts the reactive equipment in the station to achieve the target; when the bus voltage on the low-voltage side of the main transformer exceeds the safety limit, it is determined whether the instruction issued by the dispatching AVC master station is consistent with the adjustment direction of the photovoltaic AVC substation to adjust the low-voltage side bus of the main transformer to the normal range. If the two are consistent, the instruction U issued by the dispatching AVC master station is still followed. set If the two adjustment directions are inconsistent, the low-voltage bus B that exceeds the limit i , the voltage safety upper limit is U i sup, the voltage safety lower limit is U i sdn, bus voltage value is U i real, if U i real>=Ui sup,U lset =U i sup-2×U i dead, U i dead is bus B i The control dead zone is converted to the high-voltage side U hset =U lset ×U real / U i real, where U hset Set the target estimate for the high voltage side voltage, U real is the bus voltage on the high-voltage side of the main transformer, if U hset >=U sup -2×U dead , U hset =U sup -2×U dead , if U hset <=U sdn +2×U dead , U hset =U sdn +2×U dead , considering the maximum step size limit of voltage regulation, if U hset >=U real +U maxstep , U hset =U real +U maxstep , if U hset <=U real -U maxstep , U hset =U real -U maxstep , thereby calculating the control target value U of the photovoltaic AVC substation hset , when U i real<=U i sdn,U lset =U i sdn+2×U i dead, and convert it to the high-voltage side to get U hset =U lset ×U real / U i real, considering the upper limit of bus voltage U on the high voltage side of the main transformer sup And the voltage lower limit U sdn After the constraints of voltage regulation step length and voltage regulation step length, we can get U hset , PV AVC substation with U hsetThe reactive equipment in the station is regulated as the target; when the terminal voltage of a certain number of photovoltaic inverters exceeds the safety limit, in the same way, when the instruction issued by the dispatching AVC master station is consistent with the regulation direction for adjusting the terminal voltage of the photovoltaic inverter back to the normal range, the instruction of the dispatching AVC master station is used as the control target. When the two are inconsistent, the control instruction of the dispatching AVC master station is temporarily abandoned. The maximum voltage regulation step of the photovoltaic AVC substation is set to U maxstep , and adjust with the maximum adjustment step size. If the inverter voltage is to be increased, then U hset =U real +U maxstep , if the inverter voltage is lowered, then U hset =U real -U maxstep and through the upper limit of the bus voltage U on the high voltage side of the main transformer sup And the voltage lower limit U sdn After verification, the final U hset , PV AVC substation with U hset The purpose is to adjust the reactive equipment within the station.

[0072] A possible implementation method is provided in an embodiment of the present application, wherein the control unit 420 is further configured to:

[0073] When the PV AVC substation is controlled in the correction control mode, the AVC master station controls the set Adjustment is performed, and reactive power demand is obtained through sensitivity calculation. The reactive power command value of each reactive device is calculated according to the inverter priority adjustment or equal margin adjustment algorithm, and the bus voltage of each voltage level in the booster station after adjustment by the photovoltaic AVC substation is estimated. Reactive power control commands are issued to inverters and ordinary SVG devices, and voltage control commands are issued to distributed phase-shifting condensers and grid-type SVG devices.

[0074] A possible implementation method is provided in an embodiment of the present application, wherein the control unit 420 is further configured to:

[0075] When the photovoltaic AVC substation is controlled according to the optimized control mode, it eliminates the reactive circulating current of the main transformer through reactive power replacement and balances the reactive power distribution of each reactive device.

[0076] A possible implementation method is provided in an embodiment of the present application, wherein the control unit 420 is further configured to:

[0077] For busbar equipment B in the booster station i , the voltage safety upper limit is U i sup, the voltage safety lower limit is U i sdn, B i The bus voltage value is U i real, when Ui real>=U i sup or U i real<=U i sdn, the PV AVC substation enters the emergency control mode; for the inverter equipment G i , the voltage safety upper limit is UG i sup, its lower safety limit is UG i sdn, the terminal voltage of the inverter equipment is UG i real, count all UG i real>UG i The number of sup inverter devices is N gup , count all UGi r eal <UG i The number of inverter devices in sdn is N gdn , assuming that the threshold number of the emergency control inverter of the photovoltaic AVC substation is N safe , when N gup >=N safe or N gdn >=N safe When the PV AVC substation enters the emergency control mode.

[0078] Those skilled in the art can clearly understand that the specific working processes of the systems, devices, and modules described above can refer to the corresponding processes in the aforementioned method embodiments, and for the sake of brevity, they are not further described here.

[0079] Those skilled in the art can understand that the technical solution of the present application can be essentially or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, which includes a number of program instructions, so that an electronic device (such as a personal computer, a server, or a network device, etc.) executes all or part of the steps of the method described in each embodiment of the present application when running the program instructions. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., various media that can store program codes.

[0080] Alternatively, all or part of the steps of implementing the aforementioned method embodiments may be accomplished by hardware associated with program instructions (such as electronic devices such as personal computers, servers, or network devices), and the program instructions may be stored in a computer-readable storage medium. When the program instructions are executed by a processor of an electronic device, the electronic device executes all or part of the steps of the methods described in the embodiments of the present application.

[0081] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that within the spirit and principles of the present application, they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate from the protection scope of the present application.

Claims

1. A photovoltaic AVC substation time-sharing control method taking into account assessment rules, characterized in that: include: According to the command time and assessment rules received from the AVC master station of the power grid control center, the current control time period of the photovoltaic AVC substation is determined; According to the control time period of the photovoltaic AVC substation, the control mode of the photovoltaic AVC substation is determined, and the photovoltaic AVC substation is adjusted and controlled according to the control mode of the photovoltaic AVC substation.

2. The method according to claim 1, characterized in that The control time period includes any time period among the adjustment time period, the assessment time period, and the post-assessment time period; The method of determining the current control time period of the photovoltaic AVC substation according to the received instruction time of the AVC master station of the power grid control center and the assessment rules includes: Assume that the instruction issuing cycle of the AVC master station is Tc, and the time when the photovoltaic AVC substation receives the latest control instruction from the AVC master station is T0. According to the assessment rules, the photovoltaic AVC substation has Tadj time to make adjustments. Assume T1=T0+Tadj, then the photovoltaic AVC substation control time period from T0 to T1 is the adjustment time period; according to the assessment rules, the AVC master station will collect data of Texam duration for assessment calculation. Assume T2=T1+Texam, then the photovoltaic AVC substation control time period from T1 to T2 is the assessment time period; let Tafexam=Tc-(Tadj+Texam), then the time period from T2 to T2+Tafexam is the post-assessment time period. If the next round of AVC master station instructions are issued at T3, and T3<T2+Tafexam, then the time period from T2 to T3 is the post-assessment time period; According to the defined adjustment time period, assessment time period and post-assessment time period, the current control time period of the photovoltaic AVC substation is determined.

3. The method according to claim 2, characterized in that The control mode includes any one of an emergency control mode, a correction control mode, and an optimization control mode; The method of determining the current control mode of the photovoltaic AVC substation according to the current control time period of the photovoltaic AVC substation, and performing adjustment and control according to the current control mode of the photovoltaic AVC substation, includes: When the photovoltaic AVC substation is currently in the adjustment time period, the current control mode of the photovoltaic AVC substation is determined. When the photovoltaic AVC substation is currently in the emergency control mode, if the photovoltaic AVC substation's own voltage regulation demand is opposite to the instruction issued by the dispatching AVC master station, the instruction issued by the dispatching AVC master station is temporarily abandoned, and the voltage of the bus or inverter equipment that exceeds the safety limit in the photovoltaic station is adjusted to the normal range; when the photovoltaic AVC substation is not currently in the emergency control mode, the voltage issued by the dispatching AVC master station is set. The instruction is Uset, and the control voltage of the photovoltaic AVC substation is Ureal, and the control dead zone of the photovoltaic AVC substation is Udead. When |Uset-Ureal|>=Udead, the photovoltaic AVC substation enters the correction control mode, and the photovoltaic AVC substation follows the instruction issued by the AVC master station for adjustment. When |Uset-Ureal|<Udead, the photovoltaic AVC substation does not perform optimization control, but enters the instruction leveling stage under the correction control mode, that is, sends leveling instructions to each reactive equipment.

4. The method according to claim 3, characterized in that The method of determining the current control mode of the photovoltaic AVC substation according to the current control time period of the photovoltaic AVC substation, and performing adjustment and control according to the current control mode of the photovoltaic AVC substation, includes: When the photovoltaic AVC substation is currently in the assessment time period, the current control mode of the photovoltaic AVC substation is determined. When the photovoltaic AVC substation is currently in the emergency control mode, it is adjusted according to the emergency control mode. When the photovoltaic AVC substation is not currently in the emergency control mode and Uset-Ureal|>=Udead, the photovoltaic AVC substation enters the correction control mode, and the photovoltaic AVC substation follows the instructions issued by the AVC master station to make adjustments and issue corresponding adjustment instructions to each reactive device. When |Uset-Ureal|<Udead, a leveling instruction is issued to each reactive device.

5. The method according to claim 3, characterized in that: The method of determining the current control mode of the photovoltaic AVC substation according to the current control time period of the photovoltaic AVC substation, and performing adjustment and control according to the current control mode of the photovoltaic AVC substation, includes: When the PV AVC substation is currently in the post-assessment time period, determine the current control mode of the PV AVC substation. When the PV AVC substation is currently in the emergency control mode, adjust it according to the emergency control mode. When the PV AVC substation is not currently in the emergency control mode, set the operating upper limit of the current PV AVC substation control busbar to Urunup, the operating lower limit to Urundn, and the control voltage of the PV AVC substation to Ureal. When Ureal<Urunup-2*Udead and Ureal>Urundn+2*Udead, that is, the control voltage of the PV AVC substation is within the upper and lower limits of normal operation, it is considered that the PV AVC substation enters the optimization control mode and is controlled according to the optimization control mode to eliminate the reactive circulating current of the main transformer and optimize the reactive distribution within the station.

6. The method according to any one of claims 3 to 5, characterized in that When the photovoltaic AVC substation is adjusted and controlled according to the emergency control mode, the main transformer high-voltage side bus exceeds the safety limit. At this time, it is determined whether the adjustment direction of the command sent by the dispatching master station AVC to the photovoltaic AVC substation is consistent with the bus adjustment direction for adjusting the main transformer high-voltage side bus back to the normal range. When the two are consistent, the adjustment is still carried out according to the command Uset issued by the master station AVC. If the adjustment directions of the two are inconsistent, the command issued by the master station AVC is temporarily abandoned, and the main transformer high-voltage side bus voltage is adjusted to the normal range. If the high-voltage side bus voltage Ureal>=Usup at this time, Usup is the voltage safety upper limit, then the target value of the photovoltaic AVC substation is adjusted to Usup-2×Udead, such as If at this time the high-voltage side bus voltage Ureal<=Usdn, Usdn is the voltage safety lower limit, then the target value of the photovoltaic AVC substation is adjusted to Usdn+2×Udead. After the photovoltaic AVC substation determines the adjustment target value, it adjusts the reactive equipment in the station to achieve the target; when the low-voltage side bus voltage of the main transformer exceeds the safety limit, it is determined whether the instruction issued by the dispatching AVC master station is consistent with the adjustment direction of the photovoltaic AVC substation to adjust the low-voltage side bus of the main transformer to the normal range. If the two are consistent, they are still adjusted according to the instruction Uset issued by the dispatching AVC master station. If the adjustment directions of the two are inconsistent, then for the low-voltage bus Bi that exceeds the limit, its voltage safety upper limit is Uisup, and its voltage safety lower limit is Uisdn. The bus voltage The voltage value is Uireal. If Uireal>=Uisup, Ulset=Uisup-2×Uidead, Uidead is the control dead zone of bus Bi, and it is converted to the high-voltage side Uhset=Ulset×Ureal / Uireal, where Uhset is the estimated value of the high-voltage side voltage setting target, and Ureal is the main transformer high-voltage side bus voltage. If Uhset>=Usup-2×Udead, Uhset=Usup-2×Udead, if Uhset<=Usdn+2×Udead, Uhset=Usdn+2×Udead, considering the maximum step size limit of voltage regulation, if Uhset>=Ureal+U maxstep, Uhset=Ureal+Umaxstep, if Uhset<=Ureal-Umaxstep, Uhset=Ureal-Umaxstep, thus calculating the control target value Uhset of the photovoltaic AVC substation, when Uireal<=Uisdn, Ulset=Uisdn+2×Uidead, and converting it to the high-voltage side to obtain Uhset=Ulset×Ureal / Uireal, considering the constraints of the upper limit Usup and lower limit Usdn of the bus voltage on the high-voltage side of the main transformer and the voltage regulation step limit, Uhset is obtained, and the photovoltaic AVC substation uses Uhset as the target to regulate the reactive equipment in the station;When the terminal voltage of a certain number of photovoltaic inverters exceeds the safety limit, in the same way, when the instruction issued by the dispatching AVC master station is consistent with the adjustment direction for adjusting the terminal voltage of the photovoltaic inverter back to the normal range, the instruction of the dispatching AVC master station is used as the control target. When the two are inconsistent, the control instruction of the dispatching AVC master station is temporarily abandoned, and the maximum voltage adjustment step of the photovoltaic AVC substation is set to Umaxstep, and the maximum adjustment step is used as the step size for adjustment. If the inverter voltage is to be increased, Uhset=Ureal+Umaxstep, if the inverter voltage is to be decreased, Uhset=Ureal-Umaxstep, and the final Uhset is obtained after verification of the upper limit Usup and lower limit Usdn of the bus voltage on the high-voltage side of the main transformer. The photovoltaic AVC substation uses Uhset as the target to adjust the reactive equipment in the station. ; 7. The method according to claim 6, characterized in that When the PV AVC substation is controlled according to the correction control mode, it is adjusted according to the control instruction Uset of the dispatching AVC master station. The reactive power demand is obtained through sensitivity calculation. The reactive power command values of each reactive power device are calculated according to the inverter priority adjustment or equal margin adjustment algorithm, and the bus voltages of each voltage level in the booster station after the adjustment of the PV AVC substation are estimated. For inverters and ordinary SVG devices, reactive power control commands are issued, and for distributed synchronous condensers and network-forming SVG devices, voltage control commands are issued.

8. The method according to claim 7, characterized in that When the PV AVC substation is controlled according to the optimization control mode, it eliminates the main transformer reactive power circulation through reactive power replacement and balances the reactive power distribution of each reactive power device.

9. The method according to any one of claims 3 to 5, characterized in that Judge the current control mode of the PV AVC substation, including: For the bus device Bi in the booster station, its voltage safety upper limit is Uisup, its voltage safety lower limit is Uisdn, and the bus voltage value of Bi is Uireal. When Uireal >= Uisup or Uireal <= Uisdn, the PV AVC substation enters the emergency control mode; for the inverter device Gi of the PV power station, its voltage safety upper limit is UGisup, its safety lower limit is UGisdn, and the terminal voltage of the inverter device is UGireal. The number of inverter devices with UGireal > UGisup is counted as Ngup, and the number of inverter devices with UGireal < UGisdn is counted as Ngdn. Let the emergency control inverter threshold number of the PV AVC substation be Nsafe. When Ngup >= Nsafe or Ngdn >= Nsafe, the PV AVC substation enters the emergency control mode.

10. A photovoltaic AVC substation time-sharing control device taking into account assessment rules, characterized in that: Including: A determination unit for determining the current control time period of the PV AVC substation according to the received instruction time of the AVC master station of the power grid dispatching center and the assessment rules; A control unit for determining the current control mode of the PV AVC substation according to the current control time period of the PV AVC substation and performing adjustment control according to the current control mode of the PV AVC substation.

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