Calculation Method of Reactive Power Compensation Capacitor Capacity in Distribution Network Containing Harmonics

Abstract

The invention relates to a capacity calculating method for a power distribution network reactive compensation capacitor containing harmonic waves. A background harmonic wave voltage and a load harmonic wave current are considered respectively, and a non-sine voltage-non-linear load power distribution network reactive compensation system mathematical model is established. From the perspective of compensation system fundamental wave reactive power and background harmonic wave reactive power, load parameters are combined, and the capacity calculating method for the reactive power compensation capacitor of a compensation system is derived so as to calculate the optimal capacitance of the capacitor. Compared with a conventional capacity calculating method for the compensation capacitor, the method provided by the invention can more pointedly compensate the system reactive power, effectively improve the reactive compensation situation of the power grid and improve the electric energy quality of the power grid.

Description

[0001] Technical field:

[0002] The invention relates to a method for calculating the capacity of a reactive power compensation capacitor in a distribution network containing harmonics.

[0003] Background technique:

[0004] With the widespread application of non-linear electrical equipment in the power grid, the problems of harmonic pollution, power loss and low power factor in the distribution network are becoming more and more serious. Reactive power compensation has become a key link to achieve safe and economical operation of the power grid.

[0005] The traditional reactive power compensation capacitor capacity can be determined by S 2 =P 2 +Q 2 Calculated, that is, the reactive capacitor compensation capacity is:

[0006]

[0007] In formula (1), Q is the reactive power of the system, P is the active power of the system, and S is the apparent power; in a sinusoidal circuit, S, P, and Q are the apparent power of the fundamental wave, the active power of the fundam...

Examples

Embodiment 1

[0069] Select a 10kV line in a substation, the power supply voltage is distorted, and the load is a linear load; when the system is not compensated, the three-phase voltage distortion rate of the 10kV bus is 4.66%, and the current distortion rate is 1.08%. Taking phase A as an example, the measured The harmonic content value (phase voltage amplitude) is shown in Table 1.

[0070] Table 1 Bus voltage and current harmonic content values

[0071]

[0072] When compensating according to the traditional sinusoidal reactive power definition, the capacitor capacitance value C is calculated 传 =10.262μF; when compensated according to the proposed method, the calculated capacitor capacitance C opt =10.262μF; input two sets of capacitor banks calculated by the compensation algorithm (the reactance rate is 5%), and the simulation diagram of the system’s fundamental reactive power and fundamental power factor can be obtained respectively, as shown in the attached image 3 shown.

[0...

Embodiment 2

[0075] Select a 10kV line in a substation, ignore the harmonics of the supply voltage, and the load is a nonlinear load; when the system is not compensated, the three-phase voltage distortion rate of the 10kV bus is 1.57%, and the current distortion rate is 35.03%. Taking the A phase as an example, The measured harmonic content values ​​(phase voltage amplitude) are shown in Table 2.

[0076] Table 2 Bus Voltage and Current Harmonic Content Values

[0077]

[0078] When compensating according to the traditional sinusoidal reactive power definition, the capacitor capacitance value C is calculated 传 =12.954μF; when compensated according to the proposed method, the calculated capacitor capacitance value C opt =10.806μF; put into two sets of capacitor banks calculated by the compensation algorithm (the reactance rate is 5%), and the simulation diagram of the change of the fundamental reactive power and fundamental power factor of the system can be obtained respectively, as sho...

Embodiment 3

[0081] A 10kV line in a substation is selected, the power supply voltage is distorted, and the load is a nonlinear load; when the system is not compensated, the three-phase voltage distortion rate of the 10kV bus is 3.71%, and the current distortion rate is 50.89%. Taking Phase A as an example, the measured harmonic content values ​​(phase voltage amplitude) are shown in Table 3.

[0082] Table 3 Bus voltage and current harmonic content values

[0083]

[0084] When compensating according to the traditional sinusoidal reactive power definition, the capacitor capacitance value C is calculated 传 =14.497μF; when compensated according to the proposed method, the capacitor capacitance value C is calculated opt = 11.021μF; input two sets of capacitor banks calculated by the compensation algorithm (the reactance rate is 5%), and the simulation diagram of the change of the fundamental reactive power and fundamental power factor of the system can be obtained respectively.

[0085]...

[0001] Technical field:

[0002] The invention relates to a method for calculating the capacity of a reactive power compensation capacitor in a distribution network containing harmonics.

[0003] Background technique:

[0004] With the widespread application of non-linear electrical equipment in the power grid, the problems of harmonic pollution, power loss and low power factor in the distribution network are becoming more and more serious. Reactive power compensation has become a key link to achieve safe and economical operation of the power grid.

[0005] The traditional reactive power compensation capacitor capacity can be determined by S 2 =P 2 +Q 2 Calculated, that is, the reactive capacitor compensation capacity is:

[0006]

[0007] In formula (1), Q is the reactive power of the system, P is the active power of the system, and S is the apparent power; in a sinusoidal circuit, S, P, and Q are the apparent power of the fundamental wave, the active power of the fundam...

Examples

Embodiment 1

[0069] Select a 10kV line in a substation, the power supply voltage is distorted, and the load is a linear load; when the system is not compensated, the three-phase voltage distortion rate of the 10kV bus is 4.66%, and the current distortion rate is 1.08%. Taking phase A as an example, the measured The harmonic content value (phase voltage amplitude) is shown in Table 1.

[0070] Table 1 Bus voltage and current harmonic content values

[0071]

[0072] When compensating according to the traditional sinusoidal reactive power definition, the capacitor capacitance value C is calculated 传 =10.262μF; when compensated according to the proposed method, the calculated capacitor capacitance C opt =10.262μF; input two sets of capacitor banks calculated by the compensation algorithm (the reactance rate is 5%), and the simulation diagram of the system’s fundamental reactive power and fundamental power factor can be obtained respectively, as shown in the attached image 3 shown.

[0...

Embodiment 2

[0075] Select a 10kV line in a substation, ignore the harmonics of the supply voltage, and the load is a nonlinear load; when the system is not compensated, the three-phase voltage distortion rate of the 10kV bus is 1.57%, and the current distortion rate is 35.03%. Taking the A phase as an example, The measured harmonic content values ​​(phase voltage amplitude) are shown in Table 2.

[0076] Table 2 Bus Voltage and Current Harmonic Content Values

[0077]

[0078] When compensating according to the traditional sinusoidal reactive power definition, the capacitor capacitance value C is calculated 传 =12.954μF; when compensated according to the proposed method, the calculated capacitor capacitance value C opt =10.806μF; put into two sets of capacitor banks calculated by the compensation algorithm (the reactance rate is 5%), and the simulation diagram of the change of the fundamental reactive power and fundamental power factor of the system can be obtained respectively, as sho...

Embodiment 3

[0081] A 10kV line in a substation is selected, the power supply voltage is distorted, and the load is a nonlinear load; when the system is not compensated, the three-phase voltage distortion rate of the 10kV bus is 3.71%, and the current distortion rate is 50.89%. Taking Phase A as an example, the measured harmonic content values ​​(phase voltage amplitude) are shown in Table 3.

[0082] Table 3 Bus voltage and current harmonic content values

[0083]

[0084] When compensating according to the traditional sinusoidal reactive power definition, the capacitor capacitance value C is calculated 传 =14.497μF; when compensated according to the proposed method, the capacitor capacitance value C is calculated opt = 11.021μF; input two sets of capacitor banks calculated by the compensation algorithm (the reactance rate is 5%), and the simulation diagram of the change of the fundamental reactive power and fundamental power factor of the system can be obtained respectively.

[0085]...

Images