CN-119029931-B - Subsynchronous oscillation positioning method and platform for wind power grid-connected system based on instantaneous power

CN119029931BCN 119029931 BCN119029931 BCN 119029931BCN-119029931-B

Abstract

The invention discloses a subsynchronous oscillation positioning method and platform of a wind power grid-connected system based on instantaneous power, and belongs to the field of power systems and automation thereof. The positioning method comprises the steps of detecting the instantaneous voltage and the instantaneous current of the wind power grid-connected point when subsynchronous oscillation disturbance occurs, obtaining the instantaneous power of the grid-connected point according to the instantaneous voltage and the instantaneous current, obtaining a subsynchronous period according to the instantaneous power, obtaining a disturbed direct-current component and a disturbed quadratic alternating-current component according to the subsynchronous period and the instantaneous power, obtaining subsynchronous power according to the subsynchronous period, the disturbed direct-current component and the disturbed quadratic alternating-current component, and judging whether the wind turbine generator is a subsynchronous oscillation source according to the subsynchronous power. The invention has the beneficial effects that the subsynchronous oscillation positioning method of the wind power grid-connected system based on the instantaneous power has the advantages of accurate positioning, simple calculation, short time, small workload and strong applicability.

Inventors

XU YANHUI
ZHANG LINA
YUAN ZHENHUA
WANG YAO
Cheng Yundan
TIAN XIN
ZHANG YUYUE
WEN YAN
AN PENG
Zhu Aijiu
ZHAO LONG
CHEN BO

Assignees

华北电力大学
国网山东省电力公司经济技术研究院

Dates

Publication Date: 20260512
Application Date: 20240820

Claims (7)

1. The subsynchronous oscillation positioning method of the wind power grid-connected system based on the instantaneous power is characterized by comprising the following steps of: detecting the instantaneous voltage and the instantaneous current of a wind power grid-connected point when subsynchronous oscillation disturbance occurs; obtaining the instantaneous power of the wind power grid-connected point according to the instantaneous voltage and the instantaneous current; Obtaining a secondary synchronization period according to the instantaneous power; obtaining a disturbed direct current component and a disturbed quadratic alternating current component according to the subsynchronous period and the instantaneous power; The direct current component after being disturbed is as follows: ; In the formula, As a direct current component after being disturbed, At the instant power To the point of The integration over a period of time is performed, For the instantaneous power to be available, Is a secondary synchronization period; the disturbed quadratic alternating current component is as follows: ; In the formula, As the disturbed quadratic alternating component, For the secondary synchronization period of the time period, In order to be able to take time, Is time of The instantaneous power at the time of the start, Is time of The instantaneous power at the time of the start, Is time of The instantaneous power at the time of the start, Is time of Instantaneous power at that time; Obtaining subsynchronous power according to the subsynchronous period, the disturbed direct current component and the disturbed quadratic alternating current component; Judging whether the wind turbine generator is a subsynchronous oscillation source or not according to the subsynchronous power; The subsynchronous power is: ; In the formula, For the secondary synchronization of the power, As a direct current component after being disturbed, As the disturbed quadratic alternating component, For the secondary synchronization period of the time period, Is steady state active power; When (when) When 0, the wind turbine generator is a subsynchronous oscillation source; When (when) And when the frequency is less than 0, the wind turbine generator is not a subsynchronous oscillation source.
2. The method for positioning subsynchronous oscillation of a wind power grid-connected system based on instantaneous power according to claim 1, wherein the step of obtaining the subsynchronous period is as follows: Constructing an absolute average model of the instantaneous power difference according to the instantaneous power; obtaining the minimum value of the absolute average value of the instantaneous power difference according to the absolute average value model of the instantaneous power difference; and obtaining the secondary synchronization period according to the minimum value.
3. The method for positioning subsynchronous oscillation of a wind power grid-connected system based on instantaneous power according to claim 2, wherein the absolute average model of the instantaneous power difference is as follows; ; In the formula, Is of angular frequency of The absolute average value of the instantaneous power difference at that time, In order to sample the period of time, , In order to be an instantaneous power start-up time, For the instantaneous power end time, For sampling time of The instantaneous power at the time of the start, For sampling time of The instantaneous power at the time of the start, In order to be of an angular frequency, Is the time of the ith sample.
4. The method for positioning subsynchronous oscillation of a wind power grid-connected system based on instantaneous power according to claim 3, wherein the step of obtaining the subsynchronous period is as follows: obtaining the time of the ith sampling, the instantaneous power starting time and the instantaneous power ending time and inputting the time, the instantaneous power starting time and the instantaneous power ending time into the absolute average value model of the instantaneous power difference; operating the absolute average value model of the instantaneous power difference to obtain the minimum value; obtaining a sampling period corresponding to the minimum value according to the minimum value and the absolute average value model of the instantaneous power difference; And obtaining the secondary synchronization period according to the sampling period corresponding to the minimum value.
5. The method for positioning subsynchronous oscillation of a wind power grid-connected system based on instantaneous power according to claim 4, wherein the formula for obtaining the subsynchronous period according to the sampling period corresponding to the minimum value is as follows: ; In the formula, For the secondary synchronization period of the time period, The sampling period corresponding to the minimum value of the absolute average value of the instantaneous power difference.
6. The method for positioning sub-synchronous oscillation of a wind power grid system based on instantaneous power according to any one of claims 1 to 5, wherein after the sub-synchronous period is obtained, the sub-synchronous frequency is obtained according to a sub-synchronous frequency calculation formula.
7. A platform comprising a processor and a memory, wherein the memory has stored therein computer readable instructions, the processor being configured to execute the computer readable instructions, the computer readable instructions when executed perform the instantaneous power based wind power grid tie system subsynchronous oscillation positioning method of any of claims 1-6.

Description

Subsynchronous oscillation positioning method and platform for wind power grid-connected system based on instantaneous power Technical Field The invention relates to the technical field of electric power systems and automation thereof, in particular to a subsynchronous oscillation positioning method and platform of a wind power grid-connected system based on instantaneous power. Background The large-scale wind power grid-connected system induces subsynchronous oscillation in the places such as scotland, australia and northwest China, the instantaneous voltage, current and harmonic frequency measured in each place basically covers the subsynchronous frequency band, and meanwhile, the subsynchronous oscillation has a wide propagation range, so that serious threat is brought to the safe and stable operation of the power grid. The most important method for suppressing the forced oscillation is to locate and cut off the oscillation source in time after the oscillation occurs. With the wide application of WAMS measurement systems, the data-based oscillatory source positioning method is gradually mature. The existing oscillation source positioning method based on the measurement data can be roughly summarized into a machine learning method, an energy flow method and a subsynchronous power method. The artificial intelligence method based on machine learning realizes the positioning of the oscillation source by inputting mass data and learning the connection relation between the oscillation characteristics and the position of the oscillation source. However, the machine learning calculation process has poor interpretability and unclear physical meaning. Meanwhile, the acquisition of mass data of oscillation events is limited, the completely observable requirement of the system is difficult to achieve, and the adaptability and accuracy in an actual power system are to be researched. The energy flow method firstly utilizes signal processing methods such as modal decomposition and the like to filter and obtain related signals in a subsynchronous frequency range, and further calculates the sign and the size of dissipated energy to identify an oscillation source. However, the method cannot distinguish the oscillation source unit from the unit which only contributes to negative damping, and the theoretical basis of the method needs to be further improved. Compared with other methods, the subsynchronous power method based on the instantaneous power is clear in physical meaning, meanwhile, the data acquisition is simple and easy to measure, and the requirement of on-line real-time monitoring of oscillation is met. However, the voltage and current of the subsynchronous frequency in the wind power grid-connected system can generate disturbance in phase generating links such as a phase-locked loop and droop control, further react to the voltage and current, generate multi-mode harmonic components, and enable all frequency components of the instantaneous power to change. In addition, a power frequency voltage and current related term additionally generated by phase angle disturbance exists in the subsynchronous power, when the power flow or active droop coefficient is larger, a larger power frequency voltage and current term can be generated in the non-oscillating source unit, and the true subsynchronous power is counteracted, so that misjudgment of an oscillating source is caused. Disclosure of Invention In order to solve the problems in the prior art, the invention provides a subsynchronous oscillation positioning method of a wind power grid-connected system based on instantaneous power, which is accurate in positioning, simple in calculation, short in time, small in workload and high in applicability. In order to achieve the aim of the invention, the invention provides a method for positioning a subsynchronous oscillation source of a wind power grid-connected system based on instantaneous power, which comprises the following steps: detecting the instantaneous voltage and the instantaneous current of a wind power grid-connected point when subsynchronous oscillation disturbance occurs; obtaining the instantaneous power of the wind power grid-connected point according to the instantaneous voltage and the instantaneous current; Obtaining a secondary synchronization period according to the instantaneous power; obtaining a disturbed direct current component and a disturbed quadratic alternating current component according to the subsynchronous period and the instantaneous power; Obtaining subsynchronous power according to the subsynchronous period, the disturbed direct current component and the disturbed quadratic alternating current component; And judging whether the wind turbine generator is a subsynchronous oscillation source or not according to the subsynchronous power. Further, the secondary synchronization power is: ; In the formula, For the secondary synchronization of the power,As a direct current component after being dis