Power system harmonic flow algorithm giving consideration to uncertainty and three-phase unbalance

An uncertainty and power system technology, applied in the direction of AC network with the same frequency from different sources, harmonic reduction device, multi-phase network asymmetry reduction, etc., can solve the influence of system harmonic level, uneven harmonic distribution Determinism, power component model parameter uncertainty and other issues

CN106953331APending Publication Date: 2017-07-14TIANJIN UNIV +1
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2017-07-14

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Abstract

The invention relates to a power system harmonic flow algorithm giving consideration to uncertainty and three-phase unbalance, and the algorithm comprises the steps: selecting a harmonic order h; calculating an h-th order harmonic current value of a harmonic source injection system connected with a nonlinear load node; building an h-th order harmonic model of system elements comprising all circuits and a transformer; initializing a harmonic voltage and phase angle of each node; setting the number of interaction times, and calculating the equivalent injection harmonic current value of each linear load node in each iteration process; solving the sum of the branch harmonic currents from a tail node, and obtaining the harmonic current value of each phase of each branch circuit; sequentially calculating the harmonic voltage values of the nodes from the head end of a feed line to the tail end of the feed line, wherein an iteration ending criterion is that the deviation of the harmonic voltage of each node at each phase relative to the value at the last iteration is less than an allowed value; and solving the distortion rate of the harmonic voltage of each node at each phase according to an obtained fundamental wave voltage value and the value of each harmonic voltage.
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Description

technical field

[0001] The invention relates to the field of harmonic analysis of power systems, in particular to a calculation method for three-phase unbalanced harmonic distribution of power systems based on uncertain mathematical theory.

[0002] technical background

[0003] With the emergence of the electricity market and the access of distributed power sources, there will be a large number of uncertain factors in the actual operation of the power system, such as the uncertainty of distributed power output, the uncertainty of changing loads, and the parameters of power element models. Uncertainty, etc. These factors will affect the harmonic level of the system, which will lead to uncertainty in the harmonic distribution. When the traditional deterministic harmonic distribution calculation method is used to analyze and calculate the system with uncertain information, exhibit certain limitations. Calculation of uncertain harmonic distribution has some applications in the ...

Examples

Embodiment Construction

[0053] The specific steps of the power system harmonic power flow algorithm considering uncertainty and three-phase imbalance of the present invention are as follows

[0054] 1. Obtain the results of fundamental wave power flow calculation according to requirements;

[0055] 2. Select the harmonic order h;

[0056] 3. According to the calculation results of the fundamental wave, combined with measurement, simulation, typical spectrum, etc., calculate the hth harmonic current value of the harmonic source connected to the nonlinear load node injected into the system Methods as below:

[0057] 1) The node injection power is uniformly expressed in the form of an uncertain quantity:

[0058] In the formula is the i-th phase load value of node j, i=a,b,c;

[0059] is the rated power of the i-th phase of node j;

[0060] is the noise element of the i-th phase of node j;

[0061] is the noise element coefficient;

[0062] 2) Through the three-phase fundamental wave po...