Compensation method based on mobile automatic adjustment reactive power compensation device

Abstract

The invention relates to the technical field of power grid reactive power compensation, and discloses a compensation method based on a mobile automatic adjustment reactive power compensation device, and the mobile automatic adjustment reactive power compensation device comprises a European box, an installation support and a row seat which are located in the European box, and a discharge coil installed on the row seat. The high-voltage side-by-side capacitor and the intelligent vacuum circuit breaker are mounted on the mounting bracket; a wiring terminal of the discharge coil is connected with a wiring terminal of the high-voltage side-by-side capacitor through a wire, the wiring terminal of the high-voltage side-by-side capacitor is connected with the intelligent vacuum circuit breaker through a wire, and the intelligent vacuum circuit breaker is connected with a wall bushing penetrating through the European box body through a wire. A terminal box and an automatic compensation controller are further installed in the European box, and wire bars connected with the intelligent vacuum circuit breaker and the automatic compensation controller are led out of the two ends of the terminal box respectively. According to the method, the problem that the voltage of the 10kV side of the 35kV transformer substation is too low during the load peak period is solved, and the limitation of existing fixed reactive power compensation equipment is overcome.

Description

Technical Field

[0001] The invention relates to the technical field of reactive power compensation for power grids, and in particular to a compensation method based on a mobile automatic regulating reactive power compensation device. Background Art

[0002] With the rapid development of the power system and the continuous growth of power load, the problem of reactive power compensation in the power grid has become increasingly prominent, especially in the high-voltage distribution system. Insufficient reactive power can easily lead to unstable voltage levels, affecting the normal power demand of users. Insufficient reactive power compensation will increase power loss in the power grid, reduce the operating efficiency of equipment, and in severe cases, cause the voltage to exceed the lower limit, directly affecting the normal operation of power equipment. For example, on the 10kV side of a 35kV substation, especially during busy farming seasons such as tobacco curing, the problem of low voltage is particularly serious, leading to an increase in customer complaints.

[0003] Existing technology defects:

[0004] Traditional reactive power compensation devices usually rely on fixed capacitor banks installed in substations for reactive power compensation, but such devices have the following problems:

[0005] 1. Installation space limitation: For some completed 35kV substations, there is no spare space to install new fixed reactive power compensation devices. Especially during peak load periods, the existing reactive power compensation measures can no longer meet the power demand of users.

[0006] 2. Slow response speed: Fixed reactive power compensation devices usually cannot be adjusted quickly according to load changes, especially during seasonal peak power consumption periods with large load fluctuations, such as the tobacco season. Traditional reactive power compensation equipment cannot meet the rapidly changing reactive power demand in real time.

[0007] 3. Dispersed problem: Although some substations use low-voltage reactive power compensation equipment, this compensation method is too decentralized to form effective centralized compensation. The operation is complicated and it is difficult to achieve unified management and control, resulting in unsatisfactory reactive power compensation results.

[0008] In addition, during peak load periods, the on-load voltage regulation of the main transformer of the 35kV substation and the limited fixed capacitor compensation can no longer completely solve the low voltage problem. The voltage on the user side is often too low, causing the production equipment to fail to operate normally.

[0009] In summary, existing technical solutions have obvious shortcomings in dealing with the problem of insufficient reactive power compensation in substations. It is urgent to develop a flexible, convenient and automatically adjustable reactive power compensation method to meet the needs of high-voltage distribution systems. Summary of the invention

[0010] To solve the above problems, the present invention provides a compensation method based on a mobile automatic adjustment reactive power compensation device to cope with the problem of low voltage on the 10kV side of a 35kV substation during peak load periods, thereby overcoming the limitations of existing fixed reactive power compensation equipment.

[0011] The technical solution adopted by the present invention is:

[0012] A mobile automatic adjustment reactive power compensation device comprises a European box, a mounting bracket and a row seat located in the European box, a discharge coil mounted on the row seat, and a high-voltage parallel capacitor and an intelligent vacuum circuit breaker mounted on the mounting bracket; the wiring terminals of the discharge coil are connected to the wiring terminals of the high-voltage parallel capacitor through a wire, the wiring terminals of the high-voltage parallel capacitor are connected to the intelligent vacuum circuit breaker through a wire, and the intelligent vacuum circuit breaker is connected to a wall bushing passing through the European box body through a wire; a terminal box and an automatic compensation controller are also installed in the European box, and wire rows connected to the intelligent vacuum circuit breaker and the automatic compensation controller are respectively led out from both ends of the terminal box.

[0013] Furthermore, a lightning arrester is installed on the mounting bracket. The lightning arrester is located between the high-voltage parallel capacitor and the intelligent vacuum circuit breaker, and is electrically connected to the wire connecting the high-voltage parallel capacitor and the intelligent vacuum circuit breaker.

[0014] Furthermore, the lower end of the mounting bracket is connected to a ground wire to ground the inside of the device.

[0015] Furthermore, the automatic compensation controller is respectively connected to a 220V AC power supply, an alarm relay, a current transformer and a voltage transformer installed on a high-voltage line, and performs current sampling through the current transformer and voltage sampling through the voltage transformer.

[0016] Furthermore, the automatic compensation controller calculates and displays power factor, active power, reactive power, voltage, current, voltage distortion rate, current distortion rate, 3rd to 13th order voltage and current harmonic content, real-time clock, active power, and reactive power in real time;

[0017] The reactive power compensation controller calculates the power factor PF as follows:

[0018]

[0019] Where P is the active power; S is the apparent power; θ is the phase angle between voltage and current;

[0020] The reactive power compensation controller calculates the active power as follows:

[0021] P=V·I·cosθ

[0022] Where, V is the sampling voltage; I is the sampling current; cosθ is the power factor;

[0023] The reactive power compensation controller calculates the reactive power as follows:

[0024] Q=V·I·sinθ

[0025] Where V is the sampled voltage; I is the sampled current; sinθ is the sine value of the phase angle between voltage and current;

[0026] The voltage and current are measured in real time by the voltage transformer PT and the current transformer CT;

[0027] Voltage distortion rate THD V and current distortion rate THD I , the reactive power compensation controller calculates it as follows:

[0028]

[0029]

[0030] Where V n is the voltage of the nth harmonic; V1 is the fundamental voltage; I n is the current of the nth harmonic; I1 is the fundamental current; ∞ means summing all harmonics; n=2 means starting the calculation from the second harmonic;

[0031] The reactive power compensation controller calculates the 3rd to 13th order voltage and current harmonic content as follows:

[0032]

[0033] In the formula, H n is the nth harmonic content rate; X n is the voltage or current of the nth harmonic; X1 is the voltage or current of the fundamental wave;

[0034] Reactive power compensation controller for active energy E P and reactive energy E Q The calculation is as follows:

[0035]

[0036] In the formula, T is the integration time; P is the active power; Q is the reactive power;

[0037] The reactive power compensation controller records and synchronizes time based on a real-time clock to ensure the consistency of data timing in data acquisition, statistical analysis and equipment control.

[0038] Furthermore, the reactive power compensation controller calculates and displays power factor, active power, reactive power, voltage, current, voltage distortion rate, current distortion rate, 3-13th voltage and current harmonic content, real-time clock, active power, and reactive power in real time, and can obtain the following data:

[0039] The data includes voltage, current, power factor, active power, reactive power, voltage distortion rate, current distortion rate, active energy, reactive energy at the hour of each day; daily statistics of maximum voltage and time of occurrence, minimum voltage and time of occurrence, maximum current and time of occurrence, minimum current and time of occurrence, minimum power factor and time of occurrence, maximum active power and time of occurrence, minimum active power and time of occurrence, maximum reactive power and time of occurrence, minimum reactive power and time of occurrence, maximum voltage distortion rate and time of occurrence value and time of occurrence, daily minimum value of voltage distortion rate and time of occurrence, daily maximum value of current distortion rate and time of occurrence, daily minimum value of current distortion rate and time of occurrence, daily high voltage time, daily low voltage time, daily voltage qualification rate, daily voltage distortion rate exceeding time, daily current distortion rate exceeding time, daily power factor below 0.95 time, load imbalance rate exceeding time, total operation time of 1-6 circuit capacitors, number of switching times of 1-6 circuit capacitors, power outage time, call time, number of power outages, number of calls, daily maximum current value and time of occurrence within 15 minutes;

[0040] Among them, the calculation method of reactive power compensation controller for daily voltage qualification rate is as follows:

[0041] T 合格 T is the time in a day when the voltage is within the qualified range; 总 is the total time of a day; then the daily voltage qualification rate R V The calculation formula is:

[0042]

[0043] Among them, the calculation method of the reactive power compensation controller for the load imbalance rate is as follows:

[0044] I A ,I B ,I C Represents three-phase current respectively; or P A , P B , P C Represent the three-phase power respectively; then the load unbalance rate R 不平衡 The calculation formula is:

[0045]

[0046] Or for power:

[0047]

[0048] The automatic compensation controller calculates the daily voltage qualification rate and load imbalance rate to evaluate the stability and balance of the power grid operation.

[0049] Furthermore, the automatic compensation controller fully digitally presets various control parameters, and the set parameters include: password, communication ID number, PT ratio, CT ratio, overvoltage threshold, undervoltage threshold, target power factor threshold, switching delay, distortion rate threshold, and capacitor capacity;

[0050] Among them, the automatic compensation controller calculates the PT ratio as follows:

[0051]

[0052] Where V 高压 is the high voltage side voltage, such as 10kV, 35kV, etc.; V 低压 is the low voltage side voltage, which is 100V or 110V;

[0053] The automatic compensation controller calculates the CT ratio as follows:

[0054]

[0055] In the formula, I 高电流 is the high current side current; I 低电流 is the current on the low current side;

[0056] The automatic compensation controller calculates the overvoltage and undervoltage thresholds as follows:

[0057] V 过压 =V 额定 ×(1+overvoltage ratio)

[0058] V 欠压 =V 额定 ×(1-undervoltage ratio)

[0059] Where V 过压 is the overvoltage threshold; V 欠压 is the undervoltage threshold; V 额定 is the rated voltage of the power grid;

[0060] Overvoltage ratio and undervoltage ratio can be set according to standards;

[0061] Target power factor threshold PF 目标 Set according to grid design requirements;

[0062] The switching delay is set according to the equipment and operating environment;

[0063] The distortion rate threshold is set according to the grid design standard or equipment requirements; it depends on the harmonic index requirements of the grid, usually 5% or 10%;

[0064] The automatic compensation controller needs to calculate the capacitor capacity based on the reactive power demand:

[0065] Q=V 2 ×ωC

[0066] or

[0067] In the formula, Q is the required reactive power; V is the system voltage; ω=2πf, f is the grid frequency; C is the capacitor capacity.

[0068] An automatic adjustment method for reactive power compensation, based on the above-mentioned mobile automatic adjustment reactive power compensation device, is characterized in that it comprises the following steps:

[0069] Step 1, device deployment:

[0070] According to the load demand, mobile automatic reactive compensation devices are installed between different substations, wall bushings are installed through the walls of the substations, and input power lines are introduced into European boxes;

[0071] Step 2, real-time monitoring and data collection:

[0072] Through the automatic compensation controller of the mobile automatic reactive power compensation device, the voltage, power factor and reactive power demand in the power grid are monitored in real time, and the power grid operation parameters are continuously collected, including voltage fluctuations and load change data;

[0073] Step 3. Automatic judgment and control:

[0074] When the controller of the mobile automatic reactive power compensation device detects that the voltage is low, the power factor is lower than the set standard, or the reactive power demand increases, the controller automatically determines that reactive power compensation is required;

[0075] Based on the monitored parameters, the controller calculates the required reactive power compensation capacity and issues instructions to operate the intelligent vacuum circuit breaker to put the high-voltage parallel capacitors into use;

[0076] Step 4. Reactive power compensation operation:

[0077] When the intelligent vacuum circuit breaker of the mobile automatic reactive power compensation device receives the command of the automatic compensation controller, it automatically closes, and the high-voltage parallel capacitor is connected to the power grid, and starts to provide reactive power compensation, adjust the reactive power in the system, and improve the power factor and voltage level of the power grid;

[0078] Step 5. Compensation end and capacitor removal:

[0079] When the load decreases, the grid voltage returns to normal or the power factor reaches the standard, the automatic compensation controller of the mobile automatic adjustment reactive power compensation device detects that the reactive power compensation demand decreases, automatically issues a command to control the intelligent vacuum circuit breaker to disconnect, and remove the high-voltage parallel capacitor from the grid to avoid overcompensation; after the capacitor is removed, the discharge coil automatically starts to release the residual charge in the capacitor;

[0080] Step 6, security protection mechanism:

[0081] When abnormal conditions such as overvoltage, undervoltage, overcurrent, three-phase imbalance, etc. occur, the automatic compensation controller of the mobile automatic adjustment reactive power compensation device automatically cuts off the parallel capacitors to prevent the fault from expanding, and notifies the operator through an alarm signal.

[0082] Further, in step 3, the process in which the automatic compensation controller calculates the required reactive power compensation capacity is as follows:

[0083] Step 3.1, determine the current grid parameters:

[0084] Measure the current active power P and reactive power Q 当前 ; According to the measured active power P and reactive power Q 当前 , calculate the current power factor cosθ 当前 ;

[0085] Automatic compensation controller calculates the current power factor:

[0086]

[0087] Step 3.2, determine the target power factor:

[0088] Set a target power factor cosθ 目标 , generally between 0.95 and 1.0;

[0089] Step 3.3, calculate the required reactive power compensation capacity:

[0090] The target reactive power Q is calculated by the following formula: 目标 ;

[0091] Q 目标 =P·tanθ 目标

[0092] In the formula, θ 目标 =arccos(cosθ 目标 ) is the phase angle corresponding to the target power factor; cosθ 目标 is the target power factor;

[0093] Calculate the required reactive power compensation capacity Q by the following formula: 补偿;

[0094] Q 补偿 =Q 当前 -Q 目标

[0095] In the formula, Q 补偿 is the required reactive power compensation capacity, that is, the reactive power that the automatic compensation controller needs to compensate.

[0096] Furthermore, the automatic compensation controller of the mobile automatic regulating reactive power compensation device is also connected to a zero-sequence voltage transformer ZVT installed near the neutral point of the three-phase high-voltage line to perform zero-sequence voltage detection, detect the unbalance problem of the neutral point of the power grid, and identify abnormal three-phase unbalance or ground fault;

[0097] The zero-sequence voltage transformer can capture the zero-sequence voltage signal generated when the three-phase voltage is unbalanced and transmit it to the automatic compensation controller; the automatic compensation controller is provided with a zero-sequence voltage detection circuit, which calculates the zero-sequence voltage in real time through the three-phase voltage data collected by the voltage transformer;

[0098] The calculation formula of zero sequence voltage is as follows:

[0099]

[0100] Where V0 is the zero-sequence voltage; V A 、V B 、V C is the three-phase voltage;

[0101] Based on the real-time calculation of zero-sequence voltage, the zero-sequence voltage threshold value can be set in the automatic compensation controller; when the zero-sequence voltage exceeds the threshold value, the automatic compensation controller records the abnormality, issues an alarm, and selectively disconnects the high-voltage parallel capacitors;

[0102] The set zero-sequence voltage threshold is 10V;

[0103] When V0≤10V, the grid operates normally and no action is required.

[0104] When V0>10V, the automatic compensation controller triggers an alarm and disconnects some high-voltage parallel capacitors according to the preset strategy to prevent reactive compensation from exacerbating the imbalance.

[0105] The beneficial effects of the present invention are:

[0106] The compensation method based on the mobile automatic adjustment reactive power compensation device of the present invention can effectively solve the problems of insufficient reactive power compensation, limited equipment space and complex operation in the current power system, and significantly improve the operation efficiency, stability and safety of the power grid; the specific technical effects are as follows:

[0107] 1. Improve reactive power compensation capability and improve voltage quality:

[0108] The compensation method based on the mobile automatic adjustment reactive power compensation device realizes real-time adjustment according to the grid voltage and power factor by automatically adjusting reactive power compensation. During the peak load period (such as the tobacco season), the problem of serious voltage crossing the line on the 10kV side is effectively solved, ensuring the stable operation of the power supply equipment. By compensating for reactive power, the device improves the system power factor, which increases the qualified rate of the power supply voltage by more than 10%, and greatly reduces customer complaints caused by low voltage.

[0109] 2. Reduce grid losses and save operating costs:

[0110] By automatically adjusting reactive power, the reactive power flow in the transmission line is reduced, thereby reducing the power loss in the power grid. According to the technical supervision statistics of Honghe Power Supply Bureau in 2023, the power loss caused by insufficient reactive compensation is as high as 668MWh. It is expected that after the device is put into use, it can reduce more than 80% of the power loss and greatly improve the economic benefits of the distribution system.

[0111] 3. Strong mobility and adaptability to changing scenarios:

[0112] The mobile automatic reactive power compensation device adopts a containerized design, has good mobility, and can be flexibly dispatched between different substations, especially in substations without fixed reactive power compensation equipment installed. It can be temporarily connected during seasonal load peaks to meet the reactive power compensation needs in various complex scenarios. The flexibility of the device improves the utilization rate of the equipment, avoids the problem of insufficient space for fixed compensation devices, and saves at least 20% of the equipment investment cost.

[0113] 4. Improve the safety and reliability of power grid operation:

[0114] The built-in automatic compensation controller and perfect protection system of the mobile automatic adjustment reactive power compensation device can monitor the operation status of the equipment in real time to prevent the occurrence of overvoltage, undervoltage, overcurrent, lack of phase and other faults. The discharge coil ensures safety after power failure, avoids electric shock accidents and equipment damage caused by residual charge, reduces the frequency and time of power failure due to faults, and is expected to reduce the equipment failure rate by more than 30%, thereby improving the operation safety and reliability of the power grid.

[0115] 5. Improved social benefits and customer satisfaction:

[0116] The compensation method based on the mobile automatic adjustment reactive power compensation device not only significantly improves the efficiency of power grid operation, but also reduces equipment downtime and production interruption caused by voltage problems, especially during the busy farming season, so that tobacco flue-curing equipment can operate normally and avoid economic losses. With the improvement of voltage qualification rate, customers' electricity experience and satisfaction are significantly improved, and the customer complaint rate is expected to be reduced by more than 50%.

[0117] 6. Considerable economic benefits:

[0118] After the compensation method based on the mobile automatic adjustment reactive power compensation device was put into use, it not only reduced the reactive power loss of the power grid, but also reduced the equipment damage and power outage losses caused by voltage instability. It is estimated that it can save about 1.5 million yuan in operation and maintenance costs for the power grid in one year. The mass production and promotion of the device will further bring significant economic benefits.

[0119] In summary, the compensation method based on the mobile automatic adjustment reactive power compensation device has produced remarkable effects in technology, economy and society, and has good prospects for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0120] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0121] Figure 1 It is a schematic diagram of the overall structure of the mobile automatic adjustment reactive power compensation device of the present invention;

[0122] Figure 2 It is a schematic diagram of the internal structure of the mobile automatic adjustment reactive power compensation device of the present invention;

[0123] Figure 3 and Figure 4 It is a connection diagram of the discharge coil, high-voltage parallel capacitor, intelligent vacuum circuit breaker, terminal box and automatic compensation controller of the present invention;

[0124] Figure 5 It is the wiring diagram of the automatic compensation controller of the present invention;

[0125] In the figure: 1. European box; 2. Mounting bracket; 3. Row seat; 4. Discharge coil; 5. High-voltage parallel capacitor; 6. Intelligent vacuum circuit breaker; 7. Terminal box; 8. Automatic compensation controller; 9. Wall bushing; 10. Lightning arrester; 11. Ground wire; 12. Box door; 13. Ventilation vent. DETAILED DESCRIPTION

[0126] The following will be combined with the drawings of the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0127] In high-voltage power distribution systems, insufficient reactive power can easily lead to unstable voltage levels, affecting users' normal electricity needs; insufficient reactive compensation increases power losses in the power grid, reduces the operating efficiency of equipment, and in severe cases causes the voltage to exceed the lower limit, directly affecting the normal operation of power-consuming equipment; this embodiment provides a compensation method based on a mobile automatic reactive compensation device. The method is based on a mobile automatic reactive compensation device, and achieves stable operation of the power system by automatically adjusting the voltage, power factor and reactive power. It can perform reactive compensation flexibly and efficiently, and is suitable for substations with insufficient reactive compensation and no space for installing fixed compensation equipment. It plays an important role in voltage regulation during peak load periods.

[0128] The mobile automatic adjustment reactive power compensation device integrates capacitor banks, vacuum switches, controllers and other equipment. The details are as follows:

[0129] like Figure 1 As shown, the mobile automatic regulating reactive power compensation device comprises a European box 1, a double-opening door 12 is arranged on the front side of the European box 1, and a ventilation vent 13 is arranged on the box body of the European box 1; the European box 1 is convenient for moving and carrying; when the device is in operation, heat will be dissipated so that the internal temperature of the whole device increases, and the internal temperature can be ventilated and cooled through the ventilation vent 13; the various components in the device are installed in the box through a compact layout and are protected.

[0130] like Figure 2 , Figure 3 and Figure 4 As shown, a mounting bracket 2 and a row seat 3 are installed in the European box 1, three groups of discharge coils 4 are installed on the row seat 3, and three groups of high-voltage parallel capacitors 5 and intelligent vacuum circuit breakers 6 are installed on the mounting bracket 2 from low to high. Among them, the wiring terminals of the discharge coil 4 are connected to the wiring terminals of the high-voltage parallel capacitor 5 through a wire, and the wiring terminals of the high-voltage parallel capacitor 5 are connected to the intelligent vacuum circuit breaker 6 through a wire. The intelligent vacuum circuit breaker 6 is connected to the wall bushing 9 that passes through the box body of the European box 1 through a wire. A terminal box 7 and an automatic compensation controller 8 are also installed in the European box 1, and the two ends of the terminal box 7 lead out the wire rows connected to the intelligent vacuum circuit breaker 6 and the automatic compensation controller 8.

[0131] Based on the above settings, the automatic compensation controller 8 can control the intelligent vacuum circuit breaker 6 to remotely close and open the device and perform reactive power compensation; the intelligent vacuum circuit breaker 6 cooperates with the automatic compensation controller 8 to realize remote operation and automatic control functions. The high-voltage parallel capacitor 5 is used for reactive power compensation, improving voltage quality, reducing grid losses and improving the operating efficiency of the power system; the main reactive power compensation element of the high-voltage parallel capacitor 5 can dynamically adjust the switching of the capacitor, improve the power factor of the grid, compensate for the reactive power of the system, and improve the voltage quality. The discharge coil 4 can be used to release the residual charge in the capacitor to ensure that the residual charge in the capacitor is quickly and safely released after the equipment is powered off, so as to avoid accidental electric shock or equipment damage during live operation or maintenance, ensure the safety of equipment and operators, and prevent electric shock accidents.

[0132] In addition, considering the safety issues, such as Figure 2 , Figure 3 and Figure 4 As shown, a lightning arrester 10 is also installed on the mounting bracket 2. The lightning arrester 10 is located between the high-voltage parallel capacitor 5 and the intelligent vacuum circuit breaker 6, and is connected to the wire connected between the high-voltage parallel capacitor 5 and the intelligent vacuum circuit breaker 6; Figure 3 As shown, the lower end of the mounting bracket 2 is connected to the ground wire 11 to ground the inside of the device. The lightning arrester 10 plays a role in preventing voltage surges and protecting the electrical components in the device from being damaged by transient overvoltage.

[0133] The terminal box 7 is installed on the side and back of the European box 1, and is connected to the intelligent vacuum circuit breaker 6 and the automatic compensation controller 8 through the wire row. The terminal box 7 is responsible for the convergence and distribution of electrical connections. The automatic compensation controller 8 is the core control module. By monitoring the voltage, reactive power and power factor in the power grid, it automatically adjusts the switching of the high-voltage parallel capacitor 5 to ensure the reactive compensation demand of the power grid when the load fluctuates. In addition, the automatic compensation controller 8 has an intelligent control function and can be remotely operated through the dispatching center, which greatly improves the intelligence level of the equipment.

[0134] The wiring diagram of the automatic compensation controller 8 in this embodiment is as follows: Figure 5 As shown, interfaces 1 and 3 of the automatic compensation controller 8 are connected to a 220V AC power supply, and interface 2 is grounded; interfaces 4 and 5 are connected to capacitors for current sampling, and interface 6 can be connected to a common end; interfaces 7 and 8 are connected to another capacitor for current sampling, and interface 9 can be connected to a common end; interfaces 10 and 11 can be connected to a current transformer installed on a high-voltage line for current sampling; interfaces 12 and 13 can be connected to a voltage transformer installed on a high-voltage line for voltage sampling; interface 14 is a common input terminal for outputting control signals; interfaces 15 to 20 are 6-way drive outputs, with AC220 / 5A per branch; interfaces 31 and 33 are connected to alarm relays.

[0135] Function 1 of automatic compensation controller 8:

[0136] Based on the above connection relationship, the reactive power compensation controller calculates and displays the power factor, active power, reactive power, voltage, current, voltage distortion rate, current distortion rate, 3rd to 13th voltage and current harmonic content, real-time clock, active power, reactive power, etc. in real time;

[0137] (1) Real-time calculation and display of power factor:

[0138] The power factor PF is the ratio of active power to apparent power in the power grid. The reactive power compensation controller calculates it as follows:

[0139]

[0140] Where P is the active power; S is the apparent power; and θ is the phase angle between voltage and current.

[0141] (2) Real-time calculation of active power:

[0142] Active power is used for actual work, and the reactive power compensation controller calculates it as follows:

[0143] P=V·I·cosθ

[0144] Where V is the sampling voltage; I is the sampling current; cosθ is the power factor.

[0145] (3) Real-time calculation of reactive power:

[0146] Reactive power is used to maintain the electromagnetic field of the power grid, and the reactive power compensation controller calculates it as follows:

[0147] Q=V·I·sinθ

[0148] Where V is the sampled voltage; I is the sampled current; sinθ is the sine value of the phase angle between the voltage and the current.

[0149] (4) Voltage and current:

[0150] The voltage and current are measured in real time by the voltage transformer PT and the current transformer CT.

[0151] (5) Real-time calculation of voltage distortion rate and current distortion rate:

[0152] Voltage distortion rate THD V and current distortion rate THD I , the reactive power compensation controller calculates it as follows:

[0153]

[0154] Where V nis the voltage of the nth harmonic; V1 is the fundamental voltage; I n is the current of the nth harmonic; I1 is the fundamental current; ∞ It means to sum all harmonics; n=2 means to start the calculation from the second harmonic.

[0155] (6) Calculate the 3rd to 13th harmonic content of voltage and current:

[0156] The 3rd to 13th harmonic content is used to evaluate the specific harmonic components in the system to identify the voltage and current harmonic content of the specific frequency in the system. The reactive power compensation controller calculates it as follows:

[0157]

[0158] In the formula, H n is the nth harmonic content rate; X n is the voltage or current of the nth harmonic; X1 is the voltage or current of the fundamental wave.

[0159] (7) Real-time calculation of active and reactive energy:

[0160] Active energy E P and reactive energy E Q They are respectively the integral of active and reactive power per unit time, and the reactive compensation controller calculates them as follows:

[0161]

[0162] Where T is the integration time; P is the active power; Q is the reactive power.

[0163] (8) Real-time clock

[0164] The reactive power compensation controller records and synchronizes time based on a real-time clock to ensure the consistency of data timing in data acquisition, statistical analysis and equipment control.

[0165] The second function of automatic compensation controller 8:

[0166] The reactive power compensation controller can store massive data at 24 o'clock every day and daily statistical data for at least 200 days, which can be expanded to 800 days according to user requirements. The data includes voltage, current, power factor, active power, reactive power, voltage distortion rate, current distortion rate, active energy, reactive energy at the hour of each day; daily statistics of maximum voltage and time of occurrence, minimum voltage and time of occurrence, maximum current and time of occurrence, minimum current and time of occurrence, minimum power factor and time of occurrence, maximum active power and time of occurrence, minimum active power and time of occurrence, maximum reactive power and time of occurrence, minimum reactive power and time of occurrence, maximum voltage distortion rate and time of occurrence value and time of occurrence, daily minimum value of voltage distortion rate and time of occurrence, daily maximum value of current distortion rate and time of occurrence, daily minimum value of current distortion rate and time of occurrence, daily high voltage time, daily low voltage time, daily voltage qualification rate, daily voltage distortion rate exceeding time, daily current distortion rate exceeding time, daily power factor below 0.95 time, load imbalance rate exceeding time, total operation time of 1-6 capacitors, number of switching on and off of 1-6 capacitors, power outage time, call time, number of power outages, number of calls, daily maximum current value and time of occurrence in 15 minutes.

[0167] Among them, the calculation method of reactive power compensation controller for daily voltage qualification rate is as follows:

[0168] Assumption: T 合格 T is the time in a day when the voltage is within the qualified range; 总 is the total time of a day; then the daily voltage qualification rate R V The calculation formula is:

[0169]

[0170] Among them, the calculation method of the reactive power compensation controller for the load imbalance rate is as follows:

[0171] Assumption: I A ,I B ,I C Represents three-phase current respectively; or P A , P B , P C Represent the three-phase power respectively; then the load unbalance rate R 不平衡 The calculation formula is:

[0172]

[0173] Or for power:

[0174]

[0175] The automatic compensation controller 8 calculates the daily voltage qualification rate and load imbalance rate, thereby evaluating the stability and balance of the power grid operation.

[0176] Function three of automatic compensation controller 8:

[0177] The automatic compensation controller 8 fully digitally presets various control parameter functions. The parameters that can be set include password, communication ID number, PT ratio, CT ratio, overvoltage threshold, undervoltage threshold, target power factor threshold, switching delay, distortion rate threshold, time capacitor capacity, etc.

[0178] (1) The PT transformation ratio is the ratio of the high voltage side voltage to the low voltage side voltage, which is used to convert the high voltage into the low voltage for easy measurement and control; the automatic compensation controller 8 calculates it as follows:

[0179]

[0180] Where V 高压 is the high voltage side voltage, such as 10kV, 35kV, etc.; V 低压 It is the low voltage side voltage, which is 100V or 110V.

[0181] (2) CT transformation ratio is the ratio of the current on the high current side to the current on the low current side, and is used to convert the high current into the low current for measurement; the automatic compensation controller 8 calculates it as follows:

[0182]

[0183] In the formula, I 高电流 is the high current side current; I 低电流 This is the low current side current.

[0184] (3) The overvoltage and undervoltage thresholds are the upper and lower limits of the voltage for safe operation, which are set as percentages of the rated voltage according to the grid operation standard; the automatic compensation controller 8 calculates them as follows:

[0185] V 过压 =V 额定 ×(1+overvoltage ratio)

[0186] V 欠压 =V 额定 ×(1-undervoltage ratio)

[0187] Where V 过压 is the overvoltage threshold; V 欠压 is the undervoltage threshold; V 额定 is the rated voltage of the grid.

[0188] The overvoltage ratio and undervoltage ratio can be set according to the standard.

[0189] (4) Target power factor threshold PF目标 It is the standard used by the controller to determine whether to perform reactive power compensation; it is set according to the grid design requirements.

[0190] (5) The switching delay is used to prevent short-term fluctuations in voltage or power factor from causing frequent switching of capacitors. It is set according to the equipment and operating environment.

[0191] (6) The distortion rate threshold is the upper limit of the total harmonic distortion rate THD of voltage or current, which is set according to the grid design standard or equipment requirements; it depends on the harmonic index requirements of the grid and is usually 5% or 10%.

[0192] (7) Capacitor capacity is the capacity of the reactive power compensation device used to meet the reactive power demand; the automatic compensation controller 8 needs to calculate the capacitor capacity based on the reactive power demand:

[0193] Q=V 2 ×ωC

[0194] or

[0195] In the formula, Q is the required reactive power; V is the system voltage; ω=2πf, f is the grid frequency; C is the capacitor capacity.

[0196] Function three of automatic compensation controller 8:

[0197] The automatic compensation controller 8 has RS232 and RS485 hardware protocol communication ports, adopts 101 or MODEBUS-RTU communication protocol, can use on-site communication or remote communication, can realize real-time / timed call of various power parameters, modify control parameters, remote switching of capacitors, can use short-distance wireless communication function and palm computer data on-site meter reading. It has manual switching capacitor function, which can manually switch on and off capacitors without voltage and current signals.

[0198] Function 4 of automatic compensation controller 8:

[0199] The automatic compensation controller 8 has protection functions such as overvoltage, phase loss, undervoltage, harmonic over-value, etc., and can allow or prohibit the alarm relay from being attracted through control parameters.

[0200] In summary, the mobile automatic adjustment reactive power compensation device integrates capacitor banks, vacuum switches, controllers and other equipment, and is equipped with a complete protection mechanism, including overvoltage, undervoltage, overcurrent, quick disconnection, three-phase current imbalance and other protection functions. Specifically, when the grid voltage is higher than the set value, the capacitor bank is automatically cut off. When the voltage is lower than the set value, all operation instructions are locked to prevent misoperation. When a device fails, the system automatically cuts off the faulty component to avoid over-tripping and prevent the fault from expanding. Locking function: including automatic locking functions in various scenarios, such as when the system voltage is abnormal or the control device self-check is abnormal, all control instructions are automatically locked to ensure safe and stable operation of the device. The entire device is integrated on a compact mobile platform with good transportation and loading and unloading convenience. The device can operate stably in harsh environments and can be flexibly dispatched according to the reactive power compensation needs of different substations.

[0201] Based on the regulation relationship between reactive power and voltage in the power system, the device uses high-voltage parallel capacitors 5 to compensate for the reactive power of the system in real time, and combines with an intelligent control system to quickly and accurately regulate the reactive power of the power grid to solve the problem of voltage instability. At the same time, the discharge coil 4 ensures the safe release of residual charge after power failure to avoid safety hazards. The device integrates mechanical, electrical and control systems to form an efficient reactive compensation platform suitable for 10kV high-voltage distribution systems.

[0202] Based on the mobile automatic adjustment reactive power compensation device, the compensation method based on the mobile automatic adjustment reactive power compensation device provided in this embodiment includes the following steps:

[0203] 1. Device deployment:

[0204] According to the load demand, a mobile automatic adjustment reactive power compensation device platform is installed between different substations, the wall bushing 9 is installed through the wall of the substation, and the input power line is introduced into the European box 1.

[0205] Since the device adopts the European box 1 as a whole, it can be flexibly dispatched and used between different substations according to load demand, is easy to move and install, does not require complicated operating procedures during loading and unloading, can be put into use quickly, and is particularly suitable for emergency reactive power compensation needs during seasonal load peaks.

[0206] 2. Real-time monitoring and data collection:

[0207] The voltage, power factor and reactive power demand in the power grid are monitored in real time by the automatic compensation controller 8 of the mobile automatic reactive compensation device. The automatic compensation controller 8 continuously collects power grid operation parameters, including voltage fluctuations, load changes and other data.

[0208] 3. Automatic judgment and control:

[0209] When the automatic compensation controller 8 of the mobile automatic adjustment reactive power compensation device detects that the voltage is low, the power factor is lower than the set standard, or the reactive power demand increases, the automatic compensation controller 8 automatically determines that reactive power compensation is required. According to the monitored parameters, the automatic compensation controller 8 calculates the required reactive power compensation capacity and issues a command to operate the intelligent vacuum circuit breaker 6 to put the high-voltage parallel capacitor 5 into use.

[0210] The process of the automatic compensation controller 8 calculating the required reactive power compensation capacity is as follows:

[0211] (1) Determine the current grid parameters:

[0212] Measure the current active power P and reactive power Q 当前 ; According to the measured active power P and reactive power Q 当前 , calculate the current power factor cosθ 当前 .

[0213] Automatic compensation controller 8 calculates the current power factor:

[0214]

[0215] (2) Determine the target power factor:

[0216] Set a target power factor cosθ 目标 , generally the value is between 0.95 and 1.0.

[0217] (3) Calculate the required reactive power compensation capacity:

[0218] The automatic compensation controller 8 calculates the required reactive power to achieve the target power factor.

[0219] Specifically, the target reactive power Q is calculated by the following formula: 目标 ;

[0220] Q 目标 =P·tanθ 目标

[0221] In the formula, θ 目标 =arccos(cosθ 目标 ) is the phase angle corresponding to the target power factor; cosθ 目标 is the target power factor.

[0222] Calculate the required reactive power compensation capacity Q by the following formula: 补偿 ;

[0223] Q 补偿 =Q 当前 -Q 目标

[0224] In the formula, Q 补偿 is the required reactive power compensation capacity, that is, the reactive power that the automatic compensation controller 8 needs to compensate.

[0225] By measuring the current active and reactive power and setting the target power factor, the automatic compensation controller 8 calculates the required reactive compensation capacity Q 补偿 When the automatic compensation controller 8 finds that Q 补偿 When the set threshold value is exceeded, the capacitor will be switched on to provide sufficient reactive power compensation so that the power factor of the grid reaches the target value.

[0226] 4. Reactive power compensation operation:

[0227] When the intelligent vacuum circuit breaker 6 of the mobile automatic reactive power compensation device receives the command from the automatic compensation controller 8, it automatically closes, and the high-voltage parallel capacitor 5 is connected to the power grid to start providing reactive power compensation, adjust the reactive power in the system, and improve the power factor and voltage level of the power grid.

[0228] The process is fully automatic and does not require human intervention. The mobile automatic reactive power compensation device automatically adjusts the compensation capacity according to the actual operating status of the power grid to ensure stable operation of the power grid.

[0229] 5. Compensation end and capacitor removal:

[0230] When the load decreases, the grid voltage returns to normal or the power factor reaches the standard, the automatic compensation controller 8 of the mobile automatic reactive power compensation device detects that the reactive power compensation demand decreases, and automatically issues a command to control the intelligent vacuum circuit breaker 6 to disconnect, thereby cutting off the high-voltage parallel capacitor 5 from the grid to avoid overcompensation;

[0231] After the capacitor is cut off, the discharge coil 4 automatically starts to release the residual charge in the capacitor, ensuring that the capacitor is in a safe state for subsequent maintenance operations.

[0232] Through the above process, the reactive power of the power grid can be automatically regulated, ensuring that the power grid can respond quickly when the load fluctuates, improving the operating efficiency and stability of the power grid, and at the same time having a comprehensive protection mechanism to ensure the safety of operation.

[0233] In addition, the compensation method based on the mobile automatic regulating reactive power compensation device also includes a safety protection mechanism; when abnormal conditions such as overvoltage, undervoltage, overcurrent, three-phase imbalance, etc. occur, the automatic compensation controller 8 of the mobile automatic regulating reactive power compensation device automatically cuts off the parallel capacitors to prevent the fault from expanding, and notifies the operator through an alarm signal.

[0234] In order to verify the effect of the compensation method based on the mobile automatic adjustment reactive power compensation device, this embodiment also conducted an experiment; during the experiment, the reactive power compensation test during the peak load period was carried out by connecting the device to the 10kV busbar of the 35kV substation. The data showed that after the device was put into use, the voltage on the 10kV side increased by 5%-8%, meeting the voltage requirements of users, while reducing the grid energy consumption and customer complaints caused by insufficient reactive power compensation, verifying the technical effect and economic value of the device in practical applications.

[0235] Furthermore, as a preferred technical solution of this embodiment, the secondary side circuit of the discharge coil is set to an open triangle connection, and the automatic compensation controller 8 of the mobile automatic adjustment reactive compensation device is connected to the open triangle to realize zero-sequence voltage monitoring; through zero-sequence voltage monitoring, not only the internal faults of the capacitor group can be monitored, but also the three-phase imbalance or grounding fault of the power grid can be identified, thereby improving the operating stability of the power grid.

[0236] Specifically, the open delta connection is used to monitor the zero-sequence voltage V0 of the capacitor bank in real time. The open delta connection can detect the voltage imbalance between the three phases, thereby capturing the zero-sequence voltage signal; this signal can reflect the neutral point imbalance state of the capacitor bank or the power grid. The signal is transmitted to the automatic compensation controller 8; the automatic compensation controller 8 is provided with a zero-sequence voltage monitoring circuit, which calculates the zero-sequence voltage in real time through the three-phase voltage data collected by the open delta connection.

[0237] The calculation formula of zero sequence voltage is as follows:

[0238]

[0239] Where V0 is the zero-sequence voltage; V A 、V B 、V C They are three-phase voltages respectively.

[0240] Based on the real-time calculation of the zero-sequence voltage, a zero-sequence voltage threshold value can be set in the automatic compensation controller 8; when the zero-sequence voltage exceeds the threshold value, the automatic compensation controller 8 can record the abnormality, issue an alarm, and selectively disconnect the high-voltage parallel capacitor 5 to prevent the equipment from being damaged due to three-phase imbalance.

[0241] When V0≤zero-sequence voltage exceeds the threshold value, the grid operates normally and no action is required.

[0242] When V0>zero-sequence voltage exceeds the threshold value, the automatic compensation controller 8 will consider that the capacitor bank may be abnormal or faulty, and will trigger a protection action to trip the faulty capacitor bank, thereby avoiding adverse effects on the power grid.

[0243] The calculation method for the zero-sequence voltage exceeding the threshold value is as follows:

[0244] Method 1: Calculate the zero-sequence voltage exceeding the threshold value based on the rated voltage of the power grid:

[0245] Zero-sequence voltage indicates the degree of imbalance of the three-phase power grid. When the three-phase voltage of the power grid is completely balanced, the zero-sequence voltage should be close to zero. Therefore, the zero-sequence voltage exceeds the threshold value and is determined by referring to the rated voltage of the power grid and the allowable imbalance rate; the specific calculation method is as follows:

[0246]

[0247] In the formula, is the zero-sequence voltage threshold; V 额定 The rated phase voltage of the power grid, such as the phase voltage in a 380V system is 220V; the allowable unbalance rate is set according to the power grid standard, generally 2% to 5%.

[0248] Method 2: Calculate the zero-sequence voltage exceeding the threshold value by combining historical data:

[0249] Through historical operation data, the zero-sequence voltage range under normal operation and slight imbalance is analyzed, and then the zero-sequence voltage exceeds the threshold value. This method is suitable for scenarios where specific power grids or equipment have specific operation data support. The specific calculation method is as follows:

[0250]

[0251] In the formula, is the mean value of normal zero-sequence voltage in historical data; k is the multiple coefficient beyond the normal range, usually 2 to 3; σ is the standard deviation of normal zero-sequence voltage.

[0252] Method 3: Setting the zero-sequence voltage exceeding the threshold value based on the ground fault characteristics:

[0253] The zero-sequence voltage exceeding threshold value can be set according to the zero-sequence voltage range that may be caused by ground fault. Since ground fault may cause a significant increase in zero-sequence voltage, the zero-sequence voltage exceeding threshold value can be set to an appropriate multiple higher than the normal unbalanced zero-sequence voltage; the specific calculation method is as follows:

[0254] The rated phase voltage of the power grid is V 额定 , the unbalance rate is allowed to be set to n%, then:

[0255]

[0256] The setting of the zero-sequence voltage exceeding the threshold value can generally be based on the allowable range of grid imbalance, historical data fluctuation analysis, or combined with the requirements of ground fault characteristics to ensure timely alarm in abnormal situations without frequent triggering during normal fluctuations.

[0257] By increasing the monitoring of zero-sequence voltage, the three-phase imbalance and ground fault of the power grid can be identified; once the zero-sequence voltage abnormality is detected, the automatic compensation controller will trigger the corresponding fault alarm and can choose to disconnect the capacitor bank for protection; the device can not only optimize reactive power compensation, but also improve the three-phase imbalance detection and protection capabilities of the power grid, thereby improving the stability and safety of power grid operation.

[0258] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A mobile automatic reactive power compensation device, characterized in that: The mobile automatic regulating reactive power compensation device comprises a European box, a mounting bracket and a row seat located in the European box, a discharge coil mounted on the row seat, and a high-voltage parallel capacitor and an intelligent vacuum circuit breaker mounted on the mounting bracket; the wiring terminals of the discharge coil are connected to the wiring terminals of the high-voltage parallel capacitor through a wire, the wiring terminals of the high-voltage parallel capacitor are connected to the intelligent vacuum circuit breaker through a wire, and the intelligent vacuum circuit breaker is connected to the wall bushing passing through the European box body through a wire; a terminal box and an automatic compensation controller are also installed in the European box, and wire rows connected to the intelligent vacuum circuit breaker and the automatic compensation controller are respectively led out from both ends of the terminal box.

2. The mobile automatic reactive power compensation device according to claim 1 is characterized in that: A lightning arrester is also installed on the mounting bracket. The lightning arrester is located between the high-voltage parallel capacitor and the intelligent vacuum circuit breaker and is electrically connected to the wire connected between the high-voltage parallel capacitor and the intelligent vacuum circuit breaker.

3. The mobile automatic adjustment reactive power compensation device according to claim 1 is characterized in that: The lower end of the mounting bracket is connected to a ground wire to ground the inside of the device.

4. The mobile automatic reactive power compensation device according to claim 1 is characterized in that: The automatic compensation controller is respectively connected to a 220V AC power supply, an alarm relay, a current transformer and a voltage transformer installed on a high-voltage line, and performs current sampling through the current transformer and voltage sampling through the voltage transformer.

5. The mobile automatic adjustment reactive power compensation device platform according to claim 4 is characterized in that: The automatic compensation controller calculates and displays power factor, active power, reactive power, voltage, current, voltage distortion rate, current distortion rate, 3rd to 13th order voltage and current harmonic content, real-time clock, active power, and reactive power in real time; The reactive power compensation controller calculates the power factor PF as follows: Where P is the active power; S is the apparent power; θ is the phase angle between voltage and current; The reactive power compensation controller calculates the active power as follows: P=V·I·cosθ Where, V is the sampling voltage; I is the sampling current; cosθ is the power factor; The reactive power compensation controller calculates the reactive power as follows: Q=V·I·sinθ Where V is the sampled voltage; I is the sampled current; sinθ is the sine value of the phase angle between voltage and current; The voltage and current are measured in real time by the voltage transformer PT and the current transformer CT; Voltage distortion rate THD V and current distortion rate THD I , the reactive power compensation controller calculates it as follows: Where V n is the voltage of the nth harmonic; V1 is the fundamental voltage; I n is the current of the nth harmonic; I1 is the fundamental current; ∞ means summing all harmonics; n=2 means starting the calculation from the second harmonic; The reactive power compensation controller calculates the 3rd to 13th order voltage and current harmonic content as follows: In the formula, H n is the nth harmonic content rate; X n is the voltage or current of the nth harmonic; X1 is the voltage or current of the fundamental wave; Reactive power compensation controller for active energy E P and reactive energy E Q The calculation is as follows: Where T is the integration time; P is active power; Q is reactive power; The reactive power compensation controller records and synchronizes time based on a real-time clock to ensure the consistency of data timing in data acquisition, statistical analysis and equipment control.

6. The mobile automatic reactive power compensation device platform according to claim 5 is characterized in that: The reactive power compensation controller calculates and displays power factor, active power, reactive power, voltage, current, voltage distortion rate, current distortion rate, 3rd to 13th order voltage and current harmonic content, real-time clock, active power, and reactive power in real time, and can obtain the following data: The data includes voltage, current, power factor, active power, reactive power, voltage distortion rate, current distortion rate, active energy, reactive energy at the hour of each day; daily statistics of maximum voltage and time of occurrence, minimum voltage and time of occurrence, maximum current and time of occurrence, minimum current and time of occurrence, minimum power factor and time of occurrence, maximum active power and time of occurrence, minimum active power and time of occurrence, maximum reactive power and time of occurrence, minimum reactive power and time of occurrence, maximum voltage distortion rate and time of occurrence value and time of occurrence, daily minimum value of voltage distortion rate and time of occurrence, daily maximum value of current distortion rate and time of occurrence, daily minimum value of current distortion rate and time of occurrence, daily high voltage time, daily low voltage time, daily voltage qualification rate, daily voltage distortion rate exceeding time, daily current distortion rate exceeding time, daily power factor below 0.95 time, load imbalance rate exceeding time, total operation time of 1-6 circuit capacitors, number of switching times of 1-6 circuit capacitors, power outage time, call time, number of power outages, number of calls, daily maximum current value and time of occurrence within 15 minutes; Among them, the calculation method of reactive power compensation controller for daily voltage qualification rate is as follows: T 合格 T is the time in a day when the voltage is within the qualified range; 总 is the total time of a day; then the daily voltage qualification rate R V The calculation formula is: Among them, the calculation method of the reactive power compensation controller for the load imbalance rate is as follows: I A ,I B ,I C Represents three-phase current respectively; or P A , P B , P C Represent the three-phase power respectively; then the load unbalance rate R 不平衡 The calculation formula is: Or for power: The automatic compensation controller calculates the daily voltage qualification rate and load imbalance rate to evaluate the stability and balance of the power grid operation.

7. The mobile automatic reactive power compensation device platform according to claim 5 is characterized by: The automatic compensation controller is fully digitally preset with various control parameters, and the setting parameters include: password, communication ID number, PT ratio, CT ratio, overvoltage threshold, undervoltage threshold, target power factor threshold, switching delay, distortion rate threshold, and capacitor capacity; Among them, the automatic compensation controller calculates the PT ratio as follows: Where V 高压 is the high voltage side voltage, such as 10kV, 35kV, etc.; V 低压 is the low voltage side voltage, which is 100V or 110V; The automatic compensation controller calculates the CT ratio as follows: In the formula, I 高电流 is the high current side current; I 低电流 is the current on the low current side; The automatic compensation controller calculates the overvoltage and undervoltage thresholds as follows: V 过压 =V 额定 ×(1+overvoltage ratio) V 欠压 =V 额定 ×(1-undervoltage ratio) Where V 过压 is the overvoltage threshold; V 欠压 is the undervoltage threshold; V 额定 is the rated voltage of the power grid; Overvoltage ratio and undervoltage ratio can be set according to standards; Target power factor threshold PF 目标 Set according to grid design requirements; The switching delay is set according to the equipment and operating environment; The distortion rate threshold is set according to the grid design standard or equipment requirements; it depends on the harmonic index requirements of the grid, usually 5% or 10%; The automatic compensation controller needs to calculate the capacitor capacity based on the reactive power demand: Q=V 2 ×ωC In the formula, Q is the required reactive power; V is the system voltage; ω=2πf, f is the grid frequency; C is the capacitor capacity.

8. An automatic adjustment method for reactive power compensation, the automatic adjustment method for reactive power compensation is based on the mobile automatic adjustment reactive power compensation device according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1, device deployment: According to the load demand, mobile automatic reactive compensation devices are installed between different substations, wall bushings are installed through the walls of the substations, and input power lines are introduced into European boxes; Step 2, real-time monitoring and data collection: Through the automatic compensation controller of the mobile automatic reactive power compensation device, the voltage, power factor and reactive power demand in the power grid are monitored in real time, and the power grid operation parameters are continuously collected, including voltage fluctuations and load change data; Step 3. Automatic judgment and control: When the controller of the mobile automatic reactive power compensation device detects that the voltage is low, the power factor is lower than the set standard, or the reactive power demand increases, the controller automatically determines that reactive power compensation is required; Based on the monitored parameters, the controller calculates the required reactive power compensation capacity and issues instructions to operate the intelligent vacuum circuit breaker to put the high-voltage parallel capacitors into use; Step 4. Reactive power compensation operation: When the intelligent vacuum circuit breaker of the mobile automatic reactive power compensation device receives the command of the automatic compensation controller, it automatically closes, and the high-voltage parallel capacitor is connected to the power grid, and starts to provide reactive power compensation, adjust the reactive power in the system, and improve the power factor and voltage level of the power grid; Step 5. Compensation end and capacitor removal: When the load decreases, the grid voltage returns to normal or the power factor reaches the standard, the automatic compensation controller of the mobile automatic adjustment reactive power compensation device detects that the reactive power compensation demand decreases, automatically issues a command to control the intelligent vacuum circuit breaker to disconnect, and remove the high-voltage parallel capacitor from the grid to avoid overcompensation; after the capacitor is removed, the discharge coil automatically starts to release the residual charge in the capacitor; Step 6, security protection mechanism: When abnormal conditions such as overvoltage, undervoltage, overcurrent, three-phase imbalance, etc. occur, the automatic compensation controller of the mobile automatic adjustment reactive power compensation device automatically cuts off the parallel capacitors to prevent the fault from expanding, and notifies the operator through an alarm signal.

9. The automatic adjustment method for reactive power compensation according to claim 8, characterized in that: In step 3, the process by which the automatic compensation controller calculates the required reactive power compensation capacity is as follows: Step 3.1, determine the current grid parameters: Measure the current active power P and reactive power Q 当前 ; According to the measured active power P and reactive power Q 当前 , calculate the current power factor cosθ 当前 ; Automatic compensation controller calculates the current power factor: Step 3.2, determine the target power factor: Set a target power factor cosθ 目标 , generally between 0.95 and 1.0; Step 3.3, calculate the required reactive power compensation capacity: The target reactive power Q is calculated by the following formula: 目标 ; Q 目标 =P·tanθ 目标 In the formula, θ 目标 =arccos(cosθ 目标 ) is the phase angle corresponding to the target power factor; cosθ 目标 is the target power factor; Calculate the required reactive power compensation capacity Q by the following formula: 补偿 ; Q 补偿 =Q 当前 -Q 目标 In the formula, Q 补偿 is the required reactive power compensation capacity, that is, the reactive power that the automatic compensation controller needs to compensate.

10. The automatic adjustment method for reactive power compensation according to claim 8, characterized in that: The secondary circuit of the discharge coil is set to an open triangle connection, and the automatic compensation controller of the mobile automatic adjustment reactive power compensation device is connected to the open triangle to monitor the zero-sequence voltage, monitor the internal faults of the capacitor bank, and identify the three-phase imbalance or grounding fault of the power grid; The open delta connection is used to monitor the zero-sequence voltage V0 of the capacitor bank in real time and transmit it to the automatic compensation controller; the automatic compensation controller is provided with a zero-sequence voltage monitoring circuit, which calculates the zero-sequence voltage in real time through the three-phase voltage data collected by the open delta connection; The calculation formula of zero sequence voltage is as follows: Where V0 is the zero-sequence voltage; V A 、V B 、V C is the three-phase voltage; Based on the real-time calculation of zero-sequence voltage, the zero-sequence voltage threshold value can be set in the automatic compensation controller; when the zero-sequence voltage exceeds the threshold value, the automatic compensation controller records the abnormality, issues an alarm, and selectively disconnects the high-voltage parallel capacitors; When V0≤zero-sequence voltage exceeds the threshold value, the grid operates normally and no action is required. When V0>zero-sequence voltage exceeds the threshold value, the automatic compensation controller will consider that the capacitor bank may be abnormal or faulty, and will trigger the protection action to trip the faulty capacitor bank, thereby avoiding adverse effects on the power grid; The calculation method for the zero-sequence voltage exceeding the threshold value is as follows: Method 1: Calculate the zero-sequence voltage exceeding the threshold value based on the rated voltage of the power grid: The zero-sequence voltage exceeds the threshold value and is determined by referring to the rated voltage of the power grid and the allowable unbalance rate; the specific calculation method is as follows: V0 门限 =V 额定 ×Allowable unbalance rate In the formula, is the zero-sequence voltage threshold; V 额定 is the rated phase voltage of the power grid; the allowable unbalance rate is set according to the power grid standard; Method 2: Calculate the zero-sequence voltage exceeding the threshold value by combining historical data: Through historical operation data, the zero-sequence voltage range under normal operation and slight imbalance is analyzed, and then the zero-sequence voltage exceeds the threshold value; the specific calculation method is as follows: In the formula, is the normal zero-sequence voltage mean in historical data; k is the multiple coefficient beyond the normal range; σ is the standard deviation of the normal zero-sequence voltage; Method 3: Setting the zero-sequence voltage exceeding the threshold value based on the ground fault characteristics: The zero-sequence voltage exceeds the threshold value and is set according to the zero-sequence voltage range that may be caused by the ground fault; the zero-sequence voltage exceeds the threshold value and is set to an appropriate multiple higher than the normal unbalanced zero-sequence voltage; the specific calculation method is as follows: The rated phase voltage of the power grid is V 额定 , the allowable unbalance rate is set to n%, then: The setting of the zero-sequence voltage exceeding the threshold value is based on the allowable range of grid imbalance, historical data fluctuation analysis, or combined with the requirements of ground fault characteristics to ensure timely alarm in abnormal situations without frequent triggering during normal fluctuations.

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