CN-120357496-B - New energy grid-connected broadband oscillation suppression method based on inverter damping control

Abstract

The application relates to the technical field of broadband oscillation suppression, in particular to a new energy grid-connected broadband oscillation suppression method based on inverter damping control, which comprises the steps of obtaining output current and output power of each generator set after new energy grid connection, generating capacity of a power supply side and power consumption of a load side after new energy grid connection in real time; setting a time window with preset duration, determining the harmonic influence degree of each generator set in each time window, obtaining a state evaluation value of each generator set in each time window, constructing a characteristic distribution sequence, calculating the relative difference coefficient of each time window, determining the oscillation significance degree of each time window, determining the damping coefficient of each time window, and inhibiting the broadband oscillation of new energy grid connection by combining a VSG control algorithm. According to the application, the broadband oscillation suppression of the new energy grid connection is realized by adjusting the damping characteristic of the inverter in time, so that the suppression effect of the broadband oscillation is improved, and the new energy grid connection stability is improved.

Inventors

• MENG XIANGLONG
• LIU HONGBO
• WANG CHAO
• SUN DANDAN
• PANG XIAOFENG
• Pang Dongye
• LI JIA
• LIU JIANING
• QU JIANAN
• GUO LU
• PAN YUQING
• HONG YUAN
• LIANG HAIYU
• LIU FANGMING
• PENG CHENG
• GUAN PING

Assignees

• 国网黑龙江省电力有限公司绥化供电公司
• 国家电网有限公司

Dates

Publication Date

20260505

Application Date

20250514

Claims (10)

1. 1. The new energy grid-connected broadband oscillation suppression method based on inverter damping control is characterized by comprising the following steps of: Acquiring output current and output power of each generator set after new energy grid connection, generating capacity of a power supply side and power consumption of a load side of the new energy grid connection in real time; Analyzing the proportion degree of harmonic components of the output current in each time window under each generator set on a frequency domain and the symmetrical distribution condition of inter-harmonics, and determining the harmonic influence degree of each generator set in each time window; Determining time-varying characteristic values of each generator set in each time window according to the difference change conditions of the inter-harmonic waves of the output current in each time window and other time windows in the frequency domain, and combining the harmonic wave influence values to obtain state evaluation values of each generator set in each time window; Carrying out modal decomposition on the output power of each generator set in each time window, analyzing the average level of energy of different modal components under all frequency components in a frequency domain, and the average level of the output power in each time window, and constructing a characteristic distribution sequence by combining a state evaluation value; The method comprises the steps of analyzing the proportion of the power consumption of the power generation amount of a power supply side at a load side under each time window, determining the oscillation significance of each time window by combining the relative difference coefficient, determining the damping coefficient of each time window based on the oscillation significance, and suppressing the broadband oscillation of new energy grid connection by combining a VSG control algorithm.
2. 2. The method for suppressing broadband oscillation of new energy grid connection based on inverter damping control as claimed in claim 1, wherein the further measurement process of the duty ratio is: Carrying out frequency domain analysis on all output currents of each generator set in each time window to obtain a spectrogram; the frequency components corresponding to the maximum peak value in the spectrogram are marked as fundamental wave components; the sum value of the energy corresponding to all the frequency components except the fundamental wave component in the spectrogram is recorded as the total harmonic wave; And calculating the ratio between the total harmonic quantity and the sum of energy corresponding to all frequency components in the spectrogram, and recording the ratio as the harmonic duty ratio.
3. 3. The method for suppressing broadband oscillation of new energy grid connection based on inverter damping control according to claim 2, wherein the determining the harmonic influence of each generator set in each time window comprises: The frequency components which are non-integer multiples of the fundamental wave components in the spectrogram are marked as each inter-harmonic component; calculating the measurement distance between the frequency corresponding to each inter-harmonic component and the frequency corresponding to the fundamental component, and marking the difference of the measurement distance between the inter-harmonic components with the same serial numbers on the left side and the right side of the fundamental component as the relative difference; the sum value of all the relative differences at the left side and the right side of the fundamental wave component is recorded as an asymmetric coefficient; the harmonic influence degree is the product of the asymmetric coefficient and the harmonic duty cycle.
4. 4. The method for suppressing broadband oscillation of new energy grid connection based on inverter damping control as claimed in claim 3, wherein the determining the time-varying eigenvalue of each generator set in each time window comprises: Forming a two-dimensional array by the frequencies corresponding to the inter-harmonic components in the spectrogram and the energy corresponding to the inter-harmonic components; arranging all two-dimensional arrays in the spectrogram under each time window according to the descending order of frequencies corresponding to the inter-harmonic components to form an inter-harmonic sequence; The time-varying eigenvalues are the inverse of the mean of the distances of the inter-harmonic sequences between each time window and its preceding multiple time windows.
5. 5. The method for suppressing broadband oscillation of new energy grid connection based on inverter damping control according to claim 1, wherein the obtaining the state evaluation value of each generator set in each time window comprises: calculating the average value of the harmonic influence degree of each time window and a plurality of time windows before each generator set; the state evaluation value is a product of the average value and the time-varying feature value.
6. 6. The method for suppressing the new energy grid-connected broadband oscillation based on inverter damping control as claimed in claim 1, wherein the construction process of the characteristic distribution sequence is as follows: The average value of the energy corresponding to all the frequency components in the spectrogram corresponding to each modal component is recorded as average energy; calculating the average value of all output power of each generator set in each time window, and recording the average value as average power; And forming a characteristic distribution sequence by the state evaluation value, the average power and the average energy of all modal components.
7. 7. The method for suppressing broadband oscillation of new energy grid connection based on inverter damping control as claimed in claim 1, wherein the relative difference coefficient is the sum of distances between the characteristic distribution sequences of all any two generator sets in each time window.
8. 8. The method for suppressing the grid-connected broadband oscillation of the new energy source based on the inverter damping control of claim 1, wherein the further measurement process of the duty ratio is to calculate the ratio between the average value of the generated energy of the power supply side at all times in each time window and the average value of the used energy of the load side at all times in each time window as the proportionality coefficient of each time window.
9. 9. The method for suppressing broadband oscillation of new energy grid connection based on inverter damping control according to claim 8, wherein determining the oscillation saliency of each time window comprises: and carrying out weighted summation on the relative difference coefficient and the proportional coefficient based on a preset first weight value and a preset second weight value, and then carrying out normalization processing to obtain the oscillation significance of each time window, wherein the sum of the preset first weight value and the preset second weight value is 1, and the preset first weight value is larger than the preset second weight value.
10. 10. The method for suppressing the grid-connected broadband oscillation of the new energy source based on the inverter damping control of claim 1, wherein a calculation formula of a damping coefficient D i of an ith time window is D i ＝α+(β-α)×Z i , wherein alpha is a preset minimum damping coefficient, beta is a preset maximum damping coefficient, and Z i is the oscillation significance after normalization under the ith time window.

Description

New energy grid-connected broadband oscillation suppression method based on inverter damping control Technical Field The application relates to the technical field of broadband oscillation suppression, in particular to a new energy grid-connected broadband oscillation suppression method based on inverter damping control. Background With the rapid development of new energy power generation technology, particularly large-scale access to a power grid for photovoltaic power generation and wind power generation, a power grid system presents high power electronization characteristics, the dynamic interaction of the power grid system and the power grid is complex, and broadband oscillation is easy to induce. The broadband oscillation phenomenon not only can cause fluctuation of voltage and current in the power grid, but also can seriously affect normal power utilization of power grid equipment and users. After the new energy is connected, the control performance of the inverter is critical to the stability and the electric energy quality of the new energy grid connection. The existing damping control method fails to consider that the new energy source has complex nonlinear and time-varying characteristics after grid connection, the characteristics can cause the frequency and amplitude of the broadband oscillation to change along with time, and the frequency and amplitude are influenced by the consumed proportion of the electric quantity in the new energy source power generation process, so that the difficulty of suppressing the broadband oscillation can be increased, the suppression effect on the broadband oscillation is poor, and the stability of the new energy source after grid connection is lower. Disclosure of Invention In order to solve the technical problems, the novel energy grid-connected broadband oscillation suppression method based on inverter damping control is provided to solve the existing problems. The technical problem is solved by the application by providing a new energy grid-connected broadband oscillation suppression method based on inverter damping control, which comprises the following steps: Acquiring output current and output power of each generator set after new energy grid connection, generating capacity of a power supply side and power consumption of a load side of the new energy grid connection in real time; Analyzing the proportion degree of harmonic components of the output current in each time window under each generator set on a frequency domain and the symmetrical distribution condition of inter-harmonics, and determining the harmonic influence degree of each generator set in each time window; Determining time-varying characteristic values of each generator set in each time window according to the difference change conditions of the inter-harmonic waves of the output current in each time window and other time windows in the frequency domain, and combining the harmonic wave influence values to obtain state evaluation values of each generator set in each time window; Carrying out modal decomposition on the output power of each generator set in each time window, analyzing the average level of energy of different modal components under all frequency components in a frequency domain, and the average level of the output power in each time window, and constructing a characteristic distribution sequence by combining a state evaluation value; The method comprises the steps of analyzing the proportion of the power consumption of the power generation amount of a power supply side at a load side under each time window, determining the oscillation significance of each time window by combining the relative difference coefficient, determining the damping coefficient of each time window based on the oscillation significance, and suppressing the broadband oscillation of new energy grid connection by combining a VSG control algorithm. Preferably, the further measurement of the duty cycle is: Carrying out frequency domain analysis on all output currents of each generator set in each time window to obtain a spectrogram; the frequency components corresponding to the maximum peak value in the spectrogram are marked as fundamental wave components; the sum value of the energy corresponding to all the frequency components except the fundamental wave component in the spectrogram is recorded as the total harmonic wave; And calculating the ratio between the total harmonic quantity and the sum of energy corresponding to all frequency components in the spectrogram, and recording the ratio as the harmonic duty ratio. Preferably, the determining the harmonic influence degree of each generator set in each time window includes: The frequency components which are non-integer multiples of the fundamental wave components in the spectrogram are marked as each inter-harmonic component; calculating the measurement distance between the frequency corresponding to each inter-harmonic component and the frequency correspondin