High-voltage reactive compensation method and device, computer equipment and storage medium

Abstract

The invention relates to a high-voltage reactive compensation method, which comprises the following steps of: acquiring a voltage signal in a line, and filtering the voltage signal to obtain a real-time voltage; a zero crossing point is obtained according to the real-time voltage, whether reactive power needing to be switched when the voltage is at the zero crossing point is larger than a reactive power threshold value or not is judged, if yes, switching is carried out, and if not, switching is not carried out; and switching the capacitor according to the determined switching action. According to the instantaneous voltage and the instantaneous current of the three-phase current, the instantaneous reactive power is used for accurately determining the required reactive power, and compared with a traditional method depending on average power, the reactive power required by the system can be reflected more accurately.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent distribution transformer terminals, and in particular to a high-voltage reactive power compensation method, device, computer equipment and storage medium. Background Art

[0002] In modern power systems, with the rapid development of industrial production and the widespread application of various large-scale electrical equipment, the demand for reactive power in power systems is increasing, which brings many challenges to the stable operation of power systems. The unreasonable distribution of reactive power will lead to voltage fluctuations and reduced power factor, which will increase line losses, affect power quality, and may even threaten the safe and stable operation of power systems. Therefore, it is urgent to develop a system with low requirements on system chips, which can quickly and accurately adjust the supply and demand balance of reactive power and optimize voltage quality. Summary of the invention

[0003] The object of the present invention is to provide a high voltage reactive power compensation method to solve the problems raised in the above background technology.

[0004] A first aspect of the present invention provides a high-voltage reactive power compensation method, comprising:

[0005] S1, collecting the voltage signal in the circuit, filtering the voltage signal to obtain the real-time voltage;

[0006] S2, obtaining a zero-crossing point according to the real-time voltage, judging whether the reactive power to be switched when the voltage is at the zero-crossing point is greater than the reactive power threshold, if it is greater than the reactive power threshold, switching is performed, otherwise not switching;

[0007] The zero-crossing point is obtained in the following manner:

[0008] V(t)=V max *sin(ωt+φ)

[0009] Where: V(t) is the voltage value at time t, V max is the maximum voltage, ω is the angular frequency, ω=2πf, f is the frequency, φ is the phase angle,

[0010] The first point when V(t) changes from a positive value to a negative value is the zero-crossing point;

[0011] The reactive power to be switched is obtained in the following manner:

[0012] ΔQ=Q 目标 -Q 实时 , where ΔQ is the switching reactive power;

[0013] S3. Switching the capacitor on and off according to the determined switching action.

[0014] In a possible implementation manner, the step S2 further includes:

[0015] According to the reactive power to be switched, determine the reactive power change for each switch. When ΔQ>0, switch ΔQ step , when ΔQ<0, then cut off |ΔQ step ∣, where ΔQ step is the reactive power switched in the current step;

[0016] Obtaining the zero-crossing moment of the zero-crossing point and the delay time of the monitoring circuit and the controller, and determining the switching moment according to the zero-crossing moment and the delay time;

[0017] The zero-crossing time is calculated by the following formula:

[0018] K = (kπ-φ) / ω, where K is the zero-crossing time, ω is the angular frequency, and φ is the phase angle.

[0019] The switching time is: T 投切 =K-td, K is the zero-crossing time, td is the delay time.

[0020] In a possible implementation manner, after step S3, the method further includes:

[0021] Monitor the voltage deviation change rate of the line, and adjust the target power value according to the voltage deviation change rate.

[0022] The voltage deviation change rate e cu for:

[0023] e cu =[eu(k)-eu(k-1)] / Δt, eu(k) is the voltage deviation of the Kth switching, eu(k-1) is the voltage deviation of the k-1th switching, Δt is the switching time interval,

[0024] Where eu=(UU ref ) / U ref , U is the measured voltage, U ref is the reference voltage, eu is the voltage deviation.

[0025] In a possible implementation manner, the monitoring the voltage deviation change rate of the circuit, and adjusting the target power value according to the voltage deviation change rate further comprises:

[0026] The real-time current in the monitoring circuit is cut off and the switching operation is stopped if the real-time current is greater than the current alarm value.

[0027] A second aspect of the present invention provides a high-voltage reactive power compensation device, comprising:

[0028] An acquisition module is used to acquire voltage signals and current signals in the circuit, and transmit the voltage signals to the controller module and the protection module, and transmit the current signals to the controller module;

[0029] A controller module is used to receive the voltage signal and the current signal transmitted by the acquisition module, filter the voltage signal to obtain the real-time voltage, obtain the zero-crossing point by using the control algorithm, and determine the switching scheme according to the zero-crossing point;

[0030] A protection module, used for receiving the real-time current in the main circuit, comparing the real-time current with the current alarm threshold, and cutting off the main circuit if the real-time current is greater than the current alarm threshold;

[0031] A switching switch, used to perform a switching operation, wherein the switching switch is connected to the controller module and the capacitor respectively;

[0032] The capacitor adopts a thyristor capacitor. When the real-time voltage reaches the zero point, the thyristor is triggered to turn on, so as to realize the impact-free input of the capacitor. When the current reaches the zero point, the thyristor is turned off, so as to realize the arc-free removal of the capacitor.

[0033] In a possible implementation manner, the switching switch is connected to a reactance component, and the reactance component includes two mutual inductors connected in parallel, and each of the mutual inductors is connected in series with a reactor.

[0034] In a possible implementation, the controller module includes a digital signal processor and a field programmable gate array FPGA, and the acquisition module includes a voltage transformer and a current transformer, and the voltage transformer and the current transformer collect voltage signals and current signals in the power grid in real time.

[0035] In a possible implementation manner, a temperature compensation module is further included, and the temperature compensation module is used to perform temperature compensation on the capacitor.

[0036] The third aspect of the present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the high-voltage reactive power compensation method as described in the first aspect of the present invention is implemented.

[0037] A fourth aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the high-voltage reactive power compensation method as described in the first aspect of the present invention is implemented.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. Based on the instantaneous voltage and instantaneous current of the three-phase current, the required reactive power is accurately determined using the instantaneous reactive power. Compared with the traditional method that relies on average power, it can more accurately reflect the reactive power required by the system.

[0040] 2. The introduction of delay time can more accurately determine the switching moment, making the switching operation more accurate, thereby improving the reliability of reactive power compensation and the quality of power. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic flow chart of the high-voltage reactive power compensation method of the present invention;

[0042] Figure 2 It is a structural schematic diagram of a high-voltage reactive power compensation device of the present invention;

[0043] Figure 3 FIG. 4 is a schematic diagram of a computer device in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] It should be noted that the serial numbers assigned to the components in the embodiments of the present invention, such as "first" and "second", are only used to distinguish the objects being described and do not have any order or technical meaning.

[0046] like Figure 1 As shown, a high voltage reactive power compensation method comprises the following steps:

[0047] S1, collecting the voltage signal in the circuit, filtering the voltage signal to obtain the real-time voltage;

[0048] In the present invention, the voltage signal and current signal of the power grid are collected in real time through the voltage transformer (PT) and current transformer (CT) connected to the power grid. The PT converts the high voltage of the power grid into a low voltage signal processed by a suitable controller, and the CT converts the large current into a small current signal. Among them, the converted low voltage signal is the real-time voltage.

[0049] S2, obtaining a zero-crossing point according to the real-time voltage, judging whether the reactive power to be switched when the voltage is at the zero-crossing point is greater than the reactive power threshold, if it is greater than the reactive power threshold, switching is performed, otherwise not switching;

[0050] The zero-crossing point is obtained in the following manner:

[0051] V(t)=V max *sin(ωt+φ)

[0052] Where: V(t) is the voltage value at time t, V max is the maximum voltage, ω is the angular frequency, ω=2πf, f is the frequency, φ is the phase angle,

[0053] The first point when V(t) changes from a positive value to a negative value is the zero-crossing point;

[0054] The reactive power to be switched is obtained in the following manner:

[0055] ΔQ=Q 目标 -Q 实时 , where ΔQ is the switching reactive power;

[0056] According to the reactive power to be switched, determine the reactive power change for each switch. When ΔQ>0, switch ΔQ step , when ΔQ<0, then cut off |ΔQ step ∣, where ΔQ step is the reactive power switched in the current step;

[0057] Obtaining the zero-crossing moment of the zero-crossing point and the delay time of the monitoring circuit and the controller, and determining the switching moment according to the zero-crossing moment and the delay time;

[0058] The zero-crossing time is calculated by the following formula:

[0059] K = (kπ-φ) / ω, where K is the zero-crossing time, ω is the angular frequency, and φ is the phase angle.

[0060] The switching time is: T 投切 =K-td, K is the zero-crossing time, td is the delay time.

[0061] In the present invention, Q 目标 It can be adjusted according to the previous power factors. The zero-crossing point is calculated using the maximum voltage value and the sine wave as parameters. Compared with the traditional average power calculation method, it can more accurately reflect the real-time changes in the system's reactive power. When judging the switching moment, a delay time is introduced to effectively improve the accuracy of the switching operation.

[0062] Among them, the delay time can be obtained by using the system clock to receive the signals sent by the monitoring circuit and the controller module respectively, and the time difference between the two signals is detected according to the system clock to obtain the delay time. Obtaining accurate switching time and performing effective switching according to the voltage change of the line can improve the voltage quality. At the same time, since the switching time is accurately obtained, it can respond quickly, respond to changes in reactive power at the millisecond level, adjust the reactive compensation amount in time, and maintain the stable operation of the power grid. This rapid response capability ensures that in the power system, the reactive power changes, the device can respond quickly and adjust the compensation amount, thereby maintaining the stable state of the power grid, providing a strong guarantee for the reliable operation of the power system.

[0063] S3. Switching the capacitor on and off according to the determined switching action.

[0064] Monitor the voltage deviation change rate of the line, and adjust the target power value according to the voltage deviation change rate.

[0065] The voltage deviation change rate e cu for:

[0066] e cu =[eu(k)-eu(k-1)] / Δt, eu(k) is the voltage deviation of the Kth switching, eu(k-1) is the voltage deviation of the k-1th switching, Δt is the switching time interval,

[0067] Where eu=(UU ref ) / U ref , U is the measured voltage, U ref is the reference voltage, eu is the voltage deviation.

[0068] Monitor the real-time current in the line. If the real-time current is greater than the current alarm value, cut off the main circuit and stop the switching operation. The switching and alarm information of the capacitor can be transmitted through RS232 / RS485, Can bus, Ethernet, and the operation data can be uploaded to the remote monitoring center through the communication unit of the controller module using IEC101, IEC103, IEC104, IEC61850, and ModBus communication protocols. The remote control center can issue remote control instructions based on the data of the controller communication unit to realize remote monitoring and control functions. The operator can remotely operate the reactive compensation device through the host computer in the monitoring center, such as remote switching of capacitor banks, adjustment of reactive compensation capacity, modification of control parameters, viewing of historical data and alarm information, etc., which is convenient for centralized management and unified dispatch of reactive compensation devices distributed in different geographical locations, improve the intelligent management level and operation and maintenance efficiency of the power system, and reduce operation and maintenance costs.

[0069] like Figure 2As shown, the second aspect of the present invention provides a high-voltage reactive power compensation device, comprising:

[0070] The acquisition module 10 is used to acquire the voltage signal and the current signal in the line, and transmit the voltage signal to the controller module and the protection module, and transmit the current signal to the controller module; the acquisition module acquires the voltage signal and the current signal of the power grid in real time through the voltage transformer (PT) and the current transformer (CT) connected to the power grid.

[0071] The controller module 20 is used to receive the voltage signal and current signal transmitted by the acquisition module, filter the voltage signal to obtain the real-time voltage, use the control algorithm to obtain the zero crossing point, and determine the switching scheme according to the zero crossing point; the controller module can use any control chip, and the control chip can use the method described in the high-voltage reactive power compensation method to determine the switching moment and the reactive power of the switching. The controller module includes a digital signal processor and a field programmable gate array FPGA to generate an accurate trigger pulse, and accurately adjust the trigger pulse time according to the zero crossing detection signal of the voltage or current. And the acquisition module accurately collects the grid voltage and current phase information to ensure that the trigger pulse is accurately synchronized with the zero crossing point of the voltage or current. Combining the switching advantages of the contactor and the thyristor, the thyristor is used to achieve zero-crossing switching at the switching moment to avoid surges and overvoltages, and then the contactor is closed to allow the contactor to carry current for a long time to reduce the conduction loss and heat generation of the thyristor.

[0072] The protection module 30 is used to receive the real-time current in the main circuit, compare the real-time current with the current alarm threshold, and cut off the main circuit if the real-time current is greater than the current alarm threshold;

[0073] The switching switch 40 is used to perform switching operations. The switching switch is connected to the controller module and the capacitor respectively. The switching switch is connected to a reactance component. The reactance component includes two parallel mutual inductors, and each of the mutual inductors is connected in series with a reactor.

[0074] Capacitor 50, which adopts a thyristor capacitor, when the real-time voltage reaches the zero point, the thyristor is triggered to turn on, so as to realize the impact-free input of the capacitor; when the current reaches the zero point, the thyristor is turned off, so as to realize the arc-free removal of the capacitor.

[0075] Through the collaboration of these modules, the three-phase current, voltage, active power, reactive power, harmonics, power factor and other data of the line or distribution equipment are collected and calculated. The regional control principle is used to control the switching capacitors, provide or absorb reactive power to the system, adjust the power factor of the power system, stabilize the system voltage, and reduce the transmission of reactive power in the power grid, thereby effectively compensating for reactive power, improving power quality, and reducing grid losses. The device supports centralized compensation and local random compensation, meeting the reactive power compensation needs of power systems in different scenarios.

[0076] Furthermore, the controller module, sensor, communication module, etc. are placed in a metal shielding cover to avoid external electromagnetic interference.

[0077] In addition, the reactive power compensation device of the present invention also has a temperature compensation module, and the temperature compensation module is used to perform temperature compensation on the capacitor. According to the influence of different environmental conditions (such as humidity, altitude, etc.) on the performance of electrical equipment, the switching parameters and thresholds in the control algorithm can be appropriately adjusted to ensure high-precision switching under different environments. In addition, a harmonic filter can be added to the reactive power compensation device of the present invention, and the harmonic filter can eliminate the harmonics in the device to obtain accurate values ​​of voltage signals and current signals.

[0078] The following is a brief description of the steps of switching the reactive power compensation device of the present invention:

[0079] 1. The voltage and current signals of the power grid are collected in real time through the voltage transformer (PT) and current transformer (CT) connected to the power grid. PT converts the high voltage of the power grid into a low voltage signal processed by a suitable controller module, and CT converts the high current into a low current signal. The control module uses ADC to convert these analog signals into digital signals, and then performs filtering to remove high-frequency interference signals to obtain stable voltage and current effective values. According to the collected voltage and current signals, the real-time power factor of the power grid is calculated by the calculation unit in the chip according to the power calculation formula of the AC circuit.

[0080] 2. Perform fast Fourier transform analysis on the collected voltage and current signals to calculate the value and content of each harmonic, providing data support for harmonic protection and filtering.

[0081] 3. According to the calculated power factor and the preset power factor threshold, the switching time and the switching reactive power are obtained, and the controller module determines the switching of the capacitor group according to the switching time and the switching reactive power.

[0082] 4. Continuously detect the grid voltage. When the voltage exceeds the preset overvoltage threshold, the controller module immediately stops the capacitor operation. When it is lower than the preset undervoltage protection threshold, the controller sends an undervoltage alarm signal and cuts off all the capacitor banks that have been put into operation. At the same time, the relevant data of the undervoltage event is recorded for subsequent analysis.

[0083] 5. The current in the main circuit of the device is monitored by CT. When the current exceeds the preset threshold, the controller module quickly sends a trip signal to the circuit breaker, and the protection module cuts off the main circuit to protect the device from damage caused by excessive current. At the same time, an overcurrent alarm message is sent and the overcurrent value is recorded.

[0084] 6. Use temperature sensors to detect the temperature of key equipment such as capacitors and reactors. When the temperature exceeds the preset temperature threshold, the controller sends a temperature alarm message. If it is too high, the number of capacitor groups is reduced and the temperature changes and alarm information are recorded.

[0085] 7. According to the harmonic analysis, when the content of specific harmonics exceeds the preset harmonic protection threshold, the controller filter is put into operation to reduce the filtering content, and at the same time, a harmonic alarm message is sent and the harmonic exceeding the standard value is recorded.

[0086] 8. Set the voltage protection threshold according to the rated voltage of the capacitor. If the voltage exceeds or falls below the set threshold and lasts longer than the set delay time, the controller module switches on or off the capacitor bank to prevent the capacitor from being damaged due to overvoltage, and records the relevant sampling values ​​and alarm information.

[0087] In one embodiment, Figure 3 As shown, a computer device 60 is provided, including a memory 62, a processor 61, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the processor 61 executes the computer program 63, the steps in the data processing method in the above embodiment are implemented. To avoid repetition, they are not described here. Alternatively, when the processor 61 executes the computer program 43, the functions of each module in the above high-voltage reactive power compensation device embodiment are implemented. To avoid repetition, they are not described here.

[0088] In one embodiment, a readable storage medium is provided, wherein the readable storage medium stores a computer program 63. When the computer program 63 is executed by the processor 61, the steps in the data processing method in the above embodiment are implemented. To avoid repetition, it is not described here. Alternatively, when the processor 61 executes the computer program 63, the functions of each module in the above data processing device embodiment are implemented. To avoid repetition, it is not described here.

[0089] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided by the present invention may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0090] Those skilled in the art can clearly understand that for the convenience and simplicity of description, the division of the above-mentioned functional units and modules is taken as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional modules, sub-modules and units as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high voltage reactive power compensation method, characterized in that: include: S1, collecting the voltage signal in the circuit, filtering the voltage signal to obtain the real-time voltage; S2, obtaining a zero-crossing point according to the real-time voltage, judging whether the reactive power to be switched when the voltage is at the zero-crossing point is greater than the reactive power threshold, if it is greater than the reactive power threshold, switching is performed, otherwise not switching; The zero-crossing point is obtained in the following manner: V(t)=V max *sin(ωt+φ) Where: V(t) is the voltage value at time t, V max is the maximum voltage, ω is the angular frequency, ω=2πf, f is the frequency, φ is the phase angle, The first point when V(t) changes from a positive value to a negative value is the zero-crossing point; The reactive power to be switched is obtained in the following manner: ΔQ=Q 目标 -Q 实时 , where ΔQ is the switching reactive power; S3. Switching the capacitor on and off according to the determined switching action.

2. The high voltage reactive power compensation method according to claim 1, characterized in that: The step S2 further includes: According to the reactive power to be switched, determine the reactive power change for each switch. When ΔQ>0, switch ΔQ step , when ΔQ<0, then cut off |ΔQ step ∣, where ΔQ step is the reactive power switched in the current step; Obtaining the zero-crossing moment of the zero-crossing point and the delay time of the monitoring circuit and the controller, and determining the switching moment according to the zero-crossing moment and the delay time; The zero-crossing time is calculated by the following formula: K = (kπ-φ) / ω, where K is the zero-crossing time, ω is the angular frequency, and φ is the phase angle. The switching time is: T 投切 =K-td, K is the zero-crossing time, td is the delay time.

3. The high voltage reactive power compensation method according to claim 1, characterized in that: After step S3, the method further includes: Monitor the voltage deviation change rate of the line, and adjust the target power value according to the voltage deviation change rate. The voltage deviation change rate e cu for: e cu =[eu(k)-eu(k-1)] / Δt, eu(k) is the voltage deviation of the Kth switching, eu(k-1) is the voltage deviation of the k-1th switching, Δt is the switching time interval, Where eu=(UU ref ) / U ref , U is the measured voltage, U ref is the reference voltage, eu is the voltage deviation.

4. The high voltage reactive power compensation method according to claim 1, characterized in that: The monitoring circuit voltage deviation change rate, and adjusting the target power value according to the voltage deviation change rate further comprises: The real-time current in the monitoring circuit is cut off and the switching operation is stopped if the real-time current is greater than the current alarm value.

5. A high-voltage reactive power compensation device, used to perform the high-voltage reactive power compensation according to claims 1-4, characterized in that: include: An acquisition module is used to acquire voltage signals and current signals in the circuit, and transmit the voltage signals to the controller module and the protection module, and transmit the current signals to the controller module; A controller module is used to receive the voltage signal and the current signal transmitted by the acquisition module, filter the voltage signal to obtain the real-time voltage, obtain the zero-crossing point by using the control algorithm, and determine the switching scheme according to the zero-crossing point; A protection module, used for receiving the real-time current in the main circuit, comparing the real-time current with the current alarm threshold, and cutting off the main circuit if the real-time current is greater than the current alarm threshold; A switching switch, used to perform a switching operation, wherein the switching switch is connected to the controller module and the capacitor respectively; The capacitor adopts a thyristor capacitor. When the real-time voltage reaches the zero point, the thyristor is triggered to turn on, so as to realize the impact-free input of the capacitor. When the current reaches the zero point, the thyristor is turned off, so as to realize the arc-free removal of the capacitor.

6. The high-voltage reactive power compensation device according to claim 5, characterized in that: The switching switch is connected with a reactance component, which includes two mutual inductors connected in parallel, and each of the mutual inductors is connected in series with a reactor.

7. The high-voltage reactive power compensation device according to claim 5, characterized in that: The controller module includes a digital signal processor and a field programmable gate array FPGA, and the acquisition module includes a voltage transformer and a current transformer. The voltage transformer and the current transformer collect voltage signals and current signals in the power grid in real time.

8. The high-voltage reactive power compensation device according to claim 5, characterized in that: It also includes a temperature compensation module, which is used to perform temperature compensation on the capacitor.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the high-voltage reactive power compensation method according to any one of claims 1 to 4 is implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the high-voltage reactive power compensation method according to any one of claims 1 to 4 is implemented.

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