446 research outputs found
Online Voltage Stability Assessment for Load Areas Based on the Holomorphic Embedding Method
This paper proposes an online steady-state voltage stability assessment
scheme to evaluate the proximity to voltage collapse at each bus of a load
area. Using a non-iterative holomorphic embedding method (HEM) with a proposed
physical germ solution, an accurate loading limit at each load bus can be
calculated based on online state estimation on the entire load area and a
measurement-based equivalent for the external system. The HEM employs a power
series to calculate an accurate Power-Voltage (P-V) curve at each load bus and
accordingly evaluates the voltage stability margin considering load variations
in the next period. An adaptive two-stage Pade approximants method is proposed
to improve the convergence of the power series for accurate determination of
the nose point on the P-V curve with moderate computational burden. The
proposed method is illustrated in detail on a 4-bus test system and then
demonstrated on a load area of the Northeast Power Coordinating Council (NPCC)
48-geneartor, 140-bus power system.Comment: Revised and Submitted to IEEE Transaction on Power System
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