Short-Term Voltage Stability Analysis and Enhancement Strategies for Power Systems With Photovoltaic Penetration
Wenqing Hao, Minquan Chen, Deqiang Gan
Abstract
As the photovoltaic (PV) penetration in the grid continues to rise, significant changes occur in the power source configuration of power systems, altering the short-term voltage stability characteristics of the grid. This paper theoretically analyzes the short-term voltage instability that occurs in power systems with PV penetration after large disturbances and proposes corresponding enhancement strategies. First, a reduced network is obtained by retaining voltage-sensitive nodes and simplifying other nodes. Then, based on the reduced network, a concise positive definite matrix is derived to equivalently investigate the singularity of the algebraic Jacobian. This positive definite matrix also allows for further decoupling of the influence of the power network and PV dynamics. Subsequently, the minimum eigenvalue of the positive definite matrix, defined as the Voltage Stability Index ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">VSI</i> ), is used to evaluate short-term voltage stability. When <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">VSI</i> equals 0, the algebraic Jacobian becomes singular, indicating the voltage collapse. Building upon this, voltage-vulnerable nodes are identified through the participation factors of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">VSI</i> . Furthermore, it is proved that enhancing PV transmission lines can both improve short-term voltage stability. Finally, the effectiveness of the proposed index and method is validated using the 3-machine test system, 4-machine 2-area test system, and New England 39-bus test system.