Calculation of Stable Domain of DFIG-Based Wind Farm in Series Compensated Power Systems

Bin Sun,Ping Ju,Xueping Pan,Mohammad Shahidehpour

doi:10.1109/access.2020.2975045

Abstract

Subsynchronous oscillation (SSO) has concerned scholars who work with doubly-fed induction generator (DFIG)-based wind farms which are interfaced with series compensated power systems. The critical factors impacting SSO are compensation level $K_{\mathrm {C}}$ , proportional gain of rotor side controller (RSC) current tracking control $K_{\mathrm {P3}}$ , number of DFIGs, and wind speed. In this paper, we analyze the stable domain of $K_{\mathrm {C}}$ and $K_{\mathrm {P3}}$ as it is impacted by variable and uncontrollable wind speeds. Eigenvalues are used to conduct comprehensive stability analyses of the power systems, in which participation factors are employed to identify oscillation modes, and the trajectories of all the oscillation modes versus $K_{\mathrm {C}}$ and $K_{\mathrm {P3}}$ are presented to support the identification results, time domain simulation based on Simulink is also applied to verify the conclusions. Monte Carlo simulation is conducted to simulate the variable characteristic of wind speed by sampling the Weibull distribution. The impacts of the number of DFIGs and transmission distance on the stable domain are analyzed, the stable and SSO probabilities are employed in the stable domain under a variable wind speed. The constant stable domain of $K_{\mathrm {C}}$ and $K_{\mathrm {P3}}$ is presented, the power system will remain stable under a variable wind speed in this area.

Highlights

With the rapid proliferation of wind power, series compensation capacitors have been introduced to extend the power transmission capacity and deliver bulk wind power to remote load centers efficiently
In this paper, under a variable wind speed, the stable domain of KC and KP3 for doubly-fed induction generator (DFIG)-based wind farm interfaced with series compensated power system is studied
Eigenvalue analysis is applied to the studied system, and the obtained oscillation modes are identified by the participation factors

Summary

INTRODUCTION

With the rapid proliferation of wind power, series compensation capacitors have been introduced to extend the power transmission capacity and deliver bulk wind power to remote load centers efficiently. According to the references above, SSO is an electrical oscillation associated closely with wind speed, number of DFIGs, series compensation level KC, and proportional gain of rotor side controller (RSC) current tracking control KP3. The main work of this paper is to analyze and measure the stable domain of DFIG-based wind farm interfaced with series compensated power system considering a variable wind speed. CALCULATION OF THE STABLE DOMAIN UNDER A VARIABLE WIND SPEED The wind speed Vw, numbers of DFIGs N , compensation level KC and proportional gain KP3 greatly impact the SSO mode. The stable domain decreases with increasing the transmission distance, and the unstable domain for RSC and SSO modes increase, consistent with the actual situation that SSO occurs more over long distance lines with a series compensated system [13]

STABLE DOMAIN UNDER A VARIABLE WIND SPEED

CONCLUSION