CN-121984138-A - Analysis method for influence of power coupling characteristic on power grid side

CN121984138ACN 121984138 ACN121984138 ACN 121984138ACN-121984138-A

Abstract

The application provides an analysis method of the influence of power coupling characteristics on a power grid side, which is suitable for a novel power system accessed by high-proportion new energy and power electronic equipment. The method comprises the steps of firstly deducing four types of coupling characteristics of active power and reactive power on a load side based on a ZIP model by combining two types of load parameter characteristics, then analyzing an influence mechanism of the load side on a power grid side by combining a Newton-Lapherson trend equation through a jacobian matrix, then quantifying influence degree and causal direction by adopting inverse information entropy causal reasoning, and finally generating a power grid regulation reference scheme. The application realizes accurate analysis and quantification of coupling influence and provides powerful support for safe and stable and economic operation of a novel power system.

Inventors

LIU JIACHEN
QIN CHUAN
WANG YUCHAO
CHEN JINZE
LI JIANHUA
HUANG ZHIGUANG
CAO LU
ZHANG YIJING
SUN JINWEN
LUO WEI
SHI YANQIANG
LIU YI

Assignees

国家电网有限公司华东分部

Dates

Publication Date: 20260505
Application Date: 20251223

Claims (10)

1. A method for analyzing an effect of a power coupling characteristic on a grid side, comprising: Based on ZIP model equation, combining the parameter characteristics of the traditional comprehensive load and the power electronic load, deducing the active power-reactive power coupling characteristic of the load side, wherein the coupling characteristic comprises nonlinear coupling, linear coupling, proportional coupling and uncoupled coupling; Substituting a ZIP static load model into a power deviation equation, constructing an analysis model by combining with a Newton-Laportson power flow equation, and analyzing an influence mechanism of load side active power-reactive power coupling characteristics on a power coupling relation of a power grid side under a quasi-steady state by calculating jacobian matrix elements; calculating a causal strength index between active power and reactive power of a load side and a power grid side by adopting an inverse information entropy causal reasoning method, judging a causal direction of a coupling effect according to a sign of the causal strength index, and quantifying the influence degree of the coupling characteristic of the load side on the power grid side according to a numerical value of the causal strength index; And generating a regulation and control reference scheme for safe and stable operation of the power grid side based on the analysis result of the influence mechanism and the quantized influence degree data.
2. The method according to claim 1, wherein the specific process of deriving the load side active power-reactive power coupling characteristics comprises: Based on a ZIP model equation, a second-order equation root-finding formula is utilized to obtain a general expression of the load bus voltage, wherein the ZIP model equation comprises the proportionality coefficients of constant impedance, constant current and constant power load in active power and the proportionality coefficients of constant impedance, constant current and constant power load in reactive power; Aiming at the characteristic that the parameters of the traditional comprehensive load model are positive values, discarding negative root of the voltage general expression to obtain a voltage expression of the traditional comprehensive load, and equalizing voltage values in the voltage expression to obtain the active power-reactive power coupling characteristic of the traditional comprehensive load; Aiming at the characteristic that the parameters of the power electronic load model can be negative, eliminating voltage variables based on a voltage general expression, and obtaining the active power-reactive power coupling characteristic of the power electronic load; according to the active power-reactive power coupling characteristics of the traditional comprehensive load and the power electronic load, the active power-reactive power coupling characteristics of the load sides of nonlinear coupling, linear coupling, proportional coupling and uncoupled coupling are obtained by adjusting the value combination of the proportionality coefficients.
3. The method of claim 2, wherein the ZIP model equation is: Wherein P, Q is active power and reactive power of static load respectively, P 0 、Q 0 is active power and reactive power under reference voltage respectively, U is voltage of load bus, U 0 is reference voltage, A p 、B p 、C p is the proportion of constant impedance, constant current and constant power load in active power, A q 、B q 、C q is the proportion of constant impedance, constant current and constant power load in reactive power, and A p +B p +C p =1,A q +B q +C q =1.
4. The method of claim 1, wherein analyzing the impact mechanism comprises: constructing a power deviation equation, wherein the power deviation equation is a difference equation of node injection active power, static load active power and network equation calculation injection active power, and a difference equation of node injection reactive power, static load reactive power and network equation calculation injection reactive power; Calculating the partial derivative of the active power deviation to the voltage amplitude and the partial derivative of the reactive power to the voltage amplitude in the jacobian matrix based on the power deviation equation; and determining the coupling rule of active power and reactive power on the power grid side affected by the load side by analyzing the value characteristics of the jacobian matrix elements.
5. The method of claim 1, wherein the causal strength index is expressed as: In the formula, For RIECI causal indicators between load side P-Q and grid side P-Q, S () is differential entropy, 、 Respectively the normalized and sequenced X and Y data, 、 Respectively their respective probability distributions.
6. The method of claim 1, wherein generating the regulation reference scheme comprises combining a load side coupling characteristic type, a power grid side power coupling influence law and a quantization influence degree, and formulating regulation strategies of voltage regulation, load parameter optimization or power scheduling for power grid systems with different impedance characteristics.
7. The method of any of claims 1-6, wherein the power system in quasi-steady state comprises a new power system that has access to a high proportion of new energy and a high proportion of power electronics.
8. A system for analyzing the impact of power coupling characteristics on the grid side, for performing the method of any of claims 1-7, the system comprising: the coupling characteristic deduction module is used for deducting the active power-reactive power coupling characteristic of the load side based on a ZIP model equation and combining the parameter characteristics of the traditional comprehensive load and the power electronic load, wherein the coupling characteristic comprises nonlinear coupling, linear coupling, proportional coupling and uncoupled coupling; The influence mechanism analysis module is used for substituting the ZIP static load model into a power deviation equation, constructing an analysis model by combining with the Newton-Laportson power flow equation, and analyzing an influence mechanism of load side active power-reactive power coupling characteristics on a power grid side power coupling relation under a quasi-steady state by calculating jacobian matrix elements; The influence degree quantization module is used for calculating a causal strength index between active power and reactive power of the load side and the power grid side by adopting an inverse information entropy causal reasoning method, judging a causal direction of the coupling action according to a sign of the causal strength index, and quantizing the influence degree of the load side coupling characteristic on the power grid side according to a numerical value of the causal strength index; the regulation and control scheme generation module is used for generating a regulation and control reference scheme for safe and stable operation of the power grid side based on the analysis result of the influence mechanism and the quantized influence degree data.
9. A storage medium having a computer program stored therein, wherein the computer program is arranged to perform the method of any of claims 1 to 7 when run.
10. An electronic device comprising a memory and a processor, characterized in that the memory has stored therein a computer program, the processor being arranged to run the computer program to perform the method of any of claims 1 to 7.

Description

Analysis method for influence of power coupling characteristic on power grid side Technical Field The application relates to the technical field of analysis and control of power systems, in particular to a method, a system, a medium and equipment for analyzing the influence of power coupling characteristics on a power grid side. Background With the large-scale application of high-proportion new energy power generation technology and the wide popularization of power electronic equipment in the fields of industrial production, resident life and the like, the power supply structure, the load characteristic and the operation mechanism of a power system are fundamentally changed. In a traditional power system, the adjustment of active power (P) and reactive power (Q) is relatively independent, the active power is mainly related to the stable system frequency, the active power is regulated and controlled through a speed regulation system of a generator set, the reactive power mainly influences the voltage level of a node, and the reactive power compensation device and the transformer tap adjustment are relied on, so that the coupling effect of the reactive power compensation device and the transformer tap adjustment is weak and negligible. In the prior art, the research on the P-Q coupling characteristic of a power system is mainly focused on a power grid side and a power source side. On the power supply side, aiming at new energy power generation equipment (such as a photovoltaic inverter and a wind power converter), control strategy optimization is a research hot spot, and interference of power fluctuation on the power supply side on P-Q balance of the power grid is weakened by improving phase-locked loop control, a current loop modulation algorithm and the like. Meanwhile, the existing load side related research mostly regards the load as a single characteristic element with constant power, constant impedance or constant current, and the traditional comprehensive load model is adopted for analysis, so that the P-Q coupling mechanism of the load is not fully considered. However, the prior art increasingly exposes significant technical limitations in new power systems where high proportions of new energy and high proportions of power electronics are accessed. First, the loss was studied for the load side P-Q coupling characteristics. Along with the massive grid connection of power electronic interface loads (such as electric automobile charging piles, variable frequency air conditioners, industrial frequency converters and the like), the loads are not purely passive consumption elements, and an internal control logic (such as a voltage outer ring and a power limiting strategy) and nonlinear characteristics of the loads form a strong coupling relation between P and Q, namely active power fluctuation can influence reactive power output through a control link, and voltage change or reactive power disturbance can also react to the transmission and balance of active power. However, the prior art does not develop deep mechanism deduction and type division aiming at the novel coupling characteristic of the load side, so that the cognition of the P-Q coupling mechanism of the whole system is incomplete. Secondly, the analysis of the grid side affected by the load side coupling is insufficient. In the prior art, when the P-Q coupling relation of the power grid side is analyzed, the P-Q coupling characteristic of the load side is not taken into consideration as a key influence factor, and the power grid load flow calculation and stability analysis are carried out by using a traditional load model. In actual operation, power fluctuation generated by P-Q coupling at a load side is transmitted to a power grid side through network topology, so that interaction between the power grid side P and Q is aggravated, and the influence mechanism is difficult to accurately capture by a traditional analysis method, so that accuracy of power grid running state evaluation is influenced. Furthermore, there is a lack of effective means to quantify the impact of load side coupling on the grid side. In the prior art, the influence of power coupling is judged through qualitative analysis or simulation, and the action intensity and causal direction of the P-Q coupling characteristic of the load side on the power grid side cannot be quantitatively described. The degree of coupling influence is difficult to accurately grasp by power grid dispatching personnel, a targeted regulation strategy cannot be formulated, and the improvement of the safety, stability and economic operation level of the novel power system is restricted. And finally, the load model has insufficient adaptability. The traditional comprehensive load model assumes that the load parameter is a fixed positive value, the P-Q coupling effect is not considered, the scene that the power electronic load parameter may be negative and has strong coupling characteristics cannot be adapted