A reactive power automatic compensation control device capable of performing parameter correction

Abstract

The utility model relates to a reactive automatic compensation control device capable of performing parameter correction, wherein the signal acquisition unit is connected to the sampling CT position of the reactive compensation point of the power grid, and can obtain current signals and voltage signals. The parameter setting unit includes a power factor setting module for inputting the power factor of the set metering point, a time setting module for inputting the power factor frequency of the reactive compensation monitoring point, and an equipment parameter setting module for inputting the load parameters and quantity connected between the high and low voltage sides; the analysis and processing unit is connected to the signal acquisition unit and the parameter setting unit, and the signal acquisition unit and the parameter setting unit can obtain data, and after analysis and processing, calculate the power factor of the reactive compensation monitoring point, and compare the size relationship with the set power factor of the metering point. This patent helps to reduce the difficulty of reactive compensation, improve the controllability of reactive compensation, and promote the probability of reaching the standard after reactive compensation.

Description

Technical Field

[0001] The utility model belongs to the technical field of reactive power compensation of power grid, and specifically relates to a reactive power automatic compensation control device capable of performing parameter correction. Background Art

[0002] Capacitor reactive power compensation device is a very important electrical component used in the power system. Its function is to compensate for the reactive power of the inductive load in the power system (referred to as inductive reactive power) to achieve the purpose of improving the power factor, improving the voltage quality, reducing the line loss, and increasing the output power of the system or transformer. It plays an important role in improving the voltage quality of the bus, reducing the power loss of the power grid, improving the power supply quality of the power grid, and ensuring the stable operation of the power grid system.

[0003] According to the relevant specifications, "reactive power compensation at all voltage levels should be determined according to the principles of stratification, zoning, and local balance". In response to this requirement, all medium and large enterprises are equipped with capacitor (group) compensation devices to access the low-voltage busbar for capacitor reactive power compensation. In actual operation, it is found that the metering (assessment) point for enterprises to access the power grid is generally set at the high-voltage side incoming line 10 of the power grid. At the same time, the location of the reactive power compensation point sampling CT (current transformer) is set between the low-voltage side 20 of the plant transformer 20 and the low-voltage incoming line circuit breaker connected to the 380V / 220V low-voltage busbar 40. It is called the reactive power compensation (sampling) monitoring point, see Figure 1 Due to the difference in location between the metering point and the reactive power compensation sampling point, existing compensation devices can fail to accurately adjust to the power factor required by the metering point. To eliminate this discrepancy, more accurately compensate the metering point to achieve the power factor specified by the power supply company, improve the power factor of the company's electricity consumption, and avoid the risk of fines, this is currently achieved by increasing the power factor setpoint on the low-voltage side and the power factor at the high-voltage metering point.

[0004] However, the method of increasing the power factor setting value on the low-voltage side and improving the power factor at the high-voltage side metering point has the following shortcomings: (1) it is not easy to accurately set the constant value of the power factor, which increases the difficulty of setting the constant value; (2) it causes the adjustment range of the reactive power compensation on the low-voltage side to be narrowed, and there is still a high possibility that the power factor at the metering point does not meet the standard after adjustment. Utility Model Content

[0005] In view of the problems that the reactive power compensation process in photovoltaic power generation enterprises is difficult to operate and the possibility of achieving compliance after compensation is still relatively low, in which the metering point is currently set at the high-voltage side incoming line and the sampling CT of the reactive power compensation point is set between the low-voltage side of the plant transformer and the low-voltage incoming line circuit breaker, the present invention provides a reactive power automatic compensation control device capable of performing parameter correction. With the help of the reactive power automatic compensation control device, it is helpful to reduce the difficulty of reactive power compensation operation, improve the controllability of reactive power compensation, and promote the purpose of increasing the probability of achieving compliance after reactive power compensation.

[0006] The technical solution adopted by the utility model to solve the technical problem is: a reactive power automatic compensation control device capable of performing parameter correction, comprising:

[0007] The signal acquisition unit is connected to the sampling CT position of the reactive compensation point of the power grid and can obtain the current signal from the low-voltage side current transformer and the voltage signal from the low-voltage bus;

[0008] A parameter setting unit includes a power factor setting module, a time setting module, and an equipment parameter setting module; wherein the power factor setting module can be used to input a power factor of a metering point, the time setting module can be used to input a time interval or frequency for detecting the power factor of a reactive power compensation monitoring point, and the equipment parameter setting module can be used to input operating parameters and quantity of loads connected between the high and low voltage sides;

[0009] An analysis and processing unit is connected to the signal acquisition unit and the parameter setting unit, and includes an inductive reactive power calculation module and a comparison module; wherein the inductive reactive power calculation module can obtain data from the signal acquisition unit and the parameter setting unit, analyze and process the obtained data, and calculate the power factor of the reactive compensation monitoring point; the comparison module can compare the power factor of the input set metering point with the power factor of the detected reactive compensation monitoring point.

[0010] The comparison module can feed back the comparison results to an external controller. The controller can provide corresponding feedback based on the comparison results. Specifically, if the calculated power factor of the reactive compensation monitoring point is not less than the power factor of the input metering point, the controller will provide feedback not to perform reactive compensation. Conversely, if the calculated power factor of the reactive compensation monitoring point is less than the power factor of the input metering point, the controller will calculate the reactive power difference and control the input status of the capacitor bank. It will then wait for the next power factor test of the reactive compensation sampling point to be completed and compare the two power factors. This cycle will continue until the difference between the two power factors reaches a qualified value.

[0011] Optionally, a current mutual inductance collector is provided in the signal acquisition unit to acquire the current signal.

[0012] Optionally, a voltage mutual inductance collector is provided in the signal acquisition unit for acquiring a voltage signal.

[0013] The beneficial effects of the present invention are as follows: with the help of the reactive power automatic compensation control device involved, this patent helps to reduce the difficulty of reactive power compensation operation, improve the controllability of reactive power compensation, and increase the probability of meeting the standards after reactive power compensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the locations of metering points and reactive power compensation sampling points on the power grid.

[0015] Figure 2 This is a schematic diagram of the patent being connected to the power grid.

[0016] In the figure: 10, high-voltage side incoming line, 20, plant transformer, 30, low-voltage side, 40, 380V / 220V low-voltage busbar, 50, capacitor bank. DETAILED DESCRIPTION

[0017] The structures, proportions, sizes, etc. illustrated in the drawings of the specification are only used to match the contents disclosed in the specification for the understanding and reading of those familiar with this technology. They are not used to limit the conditions for the implementation of the utility model and therefore have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed in the utility model without affecting the efficacy and purpose of the utility model. At the same time, terms such as "upper", "lower", "front", "back", and "middle" quoted in this specification are only for the convenience of description and are not used to limit the scope of the implementation of the utility model. Changes or adjustments in their relative relationships should also be considered as the scope of the implementation of the utility model without substantially changing the technical content.

[0018] like Figure 1 、 Figure 2 As shown, a reactive power automatic compensation control device connected to the power grid and capable of performing parameter correction includes a signal acquisition unit, a parameter setting unit and an analysis and processing unit.

[0019] The signal acquisition unit is connected to the sampling CT position of the reactive compensation point of the power grid and can obtain the current signal from the current transformer at the low voltage side 30 and the voltage signal from the 380V / 220V low voltage bus 40 side.

[0020] The signal acquisition unit is provided with a current mutual inductance collector for acquiring current signals.

[0021] A voltage mutual inductance collector is provided in the signal acquisition unit for acquiring voltage signals.

[0022] The parameter setting unit includes a power factor setting module, a time setting module, and a device parameter setting module. The power factor setting module can be used to input and set the power factor at the metering point on the power grid (hereinafter referred to as the set power factor). The time setting module can be used to input and set the time interval or frequency for detecting the power factor at the reactive power compensation monitoring point on the power grid, that is, the interval at which the power factor at the reactive power compensation monitoring point on the power grid is detected. The device parameter setting module can be used to input the operating parameters and quantity of each load connected between the high and low voltage sides.

[0023] The analysis and processing unit is connected to the signal acquisition unit and the parameter setting unit, and includes an inductive reactive power calculation module and a comparison module.

[0024] The inductive reactive power calculation module can obtain relevant data from the signal acquisition unit and the parameter setting unit, and analyze and process the obtained data to calculate the power factor at the reactive compensation monitoring point (hereinafter referred to as calculated power factor).

[0025] The comparison module can compare the size relationship between the set power factor and the calculated power factor.

[0026] The comparison module can feed back the comparison result between the set power factor and the calculated power factor to an external controller (not shown). The controller is connected to the capacitor bank 50 in the power grid and can control the number and parameters of the capacitors in the capacitor bank 50 actually connected to the power grid.

[0027] According to the difference in the comparison results of the size relationship, the controller can make corresponding feedback in a differentiated manner, specifically: (1) if the calculated power factor is not less than the set power factor, the controller makes a feedback instruction not to perform reactive compensation, and at this time the size between the two power factors is in a qualified numerical state; on the contrary, if the calculated power factor is less than the set power factor, the controller calculates the difference in reactive power and controls the real-time input status of the capacitor group 50 according to the difference, waits for the next power factor detection of the reactive compensation sampling point to be completed, and compares the two power factors, and repeats this cycle until the size relationship between the two power factors reaches a qualified numerical state.

[0028] Relying on the patented solution, through parameter setting and inputting relevant parameters such as the box transformer and line, as well as the input of load switching, operating parameters, etc., the inductive reactive power calculation module is used to take into account the inductive reactive capacity that needs to be supplemented, and the measured value detected on the low-voltage side 30 is superimposed and input into the reactive compensation device, ultimately keeping the power factor of the high-voltage side metering point within the specified range.

[0029] This patent enables the correction of low-voltage side compensation through parameter setting, enabling more precise setting of the power factor input constant at the metering point. Furthermore, after calculating the high-voltage side reactive power, the adjustable range of reactive power on the low-voltage side can be expanded, facilitating effective and reliable control of reactive power compensation. By setting equipment parameters and other parameters, the output of the low-voltage side reactive power compensation device can be precisely controlled, helping to avoid substandard power factor at the metering point and improving power quality.

[0030] The parameter correction calculation process associated with this patent solution is roughly as follows:

[0031] 1) CT detects the actual load current Im on the low-voltage side, converts it to I'm on the high-voltage side, and calculates the transformer inductive reactive power using the formula: Q T1 =(Ud*I′m 2 / 100Ie2+I0 / 100)*Se;

[0032] 2) CT detects the actual load voltage Um and calculates the line inductive reactive power using the formula: Q L1 =U m 2 *ω*C;

[0033] 3)Q 总 =Q T1 +Q L1 +Q 低 ;

[0034] 4) By collecting the voltage, current and phase, the active power P is calculated, and then cosφ is calculated.

[0035] Where Q is the reactive power consumed by each component, Kvar;

[0036] Ud is the transformer's impedance voltage percentage;

[0037] I m is the working current value of the transformer side that needs to be compensated, A;

[0038] Ie is the rated current value of the transformer on the side that needs to be compensated, A;

[0039] I0 is the percentage of the transformer no-load current;

[0040] Se is the rated capacity of the transformer, KVA;

[0041] U is the rated voltage of the calculated circuit, KV;

[0042] I is the working current flowing through the circuit;

[0043] ω is the grid frequency;

[0044] C is the unit capacitance of the overhead power line, generally in the range of 7 to 9 pF / m;

[0045] P is the total active power;

[0046] cosφ is the power factor.

[0047] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. The present invention is susceptible to numerous improvements without departing from the overall concept. Those skilled in the art will appreciate the potential for modification or alteration of the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations accomplished by those skilled in the art without departing from the spirit and technical principles disclosed herein shall be encompassed by the claims of the present invention.

Claims

1. A reactive power automatic compensation control device capable of performing parameter correction, characterized in that: include: A signal acquisition unit is connected to the sampling CT position of the reactive compensation point of the power grid and can obtain current signals from the low-voltage side current transformer and voltage signals from the low-voltage bus; The parameter setting unit includes a power factor setting module for inputting a power factor of a set metering point, a time setting module for inputting a power factor frequency for detecting a reactive power compensation monitoring point, and an equipment parameter setting module for inputting operating parameters and quantity of a load connected between the high and low voltage sides; The analysis and processing unit is connected to the signal acquisition unit and the parameter setting unit, and includes an inductive reactive power calculation module and a comparison module; the inductive reactive power calculation module can obtain data from the signal acquisition unit and the parameter setting unit, and analyze and process the obtained data to calculate the power factor of the reactive compensation monitoring point; the comparison module can compare the power factor of the metering point set by the input and the power factor of the reactive compensation monitoring point obtained by detection.

2. The reactive power automatic compensation control device capable of performing parameter correction according to claim 1 is characterized in that: It also includes a controller connected to the capacitor group in the power grid, and the controller can control the capacitor input status of the capacitor group; the comparison module can feed back the comparison result of the power factor of the metering point and the power factor of the reactive compensation monitoring point to the controller, so that the controller can adjust the input status of the capacitor group.

3. A reactive power automatic compensation control device capable of performing parameter correction according to claim 1 or 2, characterized in that: A current mutual inductance collector is provided in the signal acquisition unit for acquiring current signals.

4. The reactive power automatic compensation control device capable of performing parameter correction according to claim 3 is characterized in that: A voltage mutual inductance collector is provided in the signal acquisition unit for acquiring voltage signals.

5. A reactive power automatic compensation control device capable of performing parameter correction according to claim 1 or 2, characterized in that: A voltage mutual inductance collector is provided in the signal acquisition unit for acquiring voltage signals.

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