Minimum frequency estimation of power system considering governor deadbands

Abstract

The extensive existence of governor deadband has a significant influence on the minimum frequency of power system after a disturbance. However, the strong nonlinearity of deadband makes it difficult to quantify its impact on the frequency response. For this end, the backlash non‐linearity is adopted to represent for the governor with deadband. The non‐linear characteristics of governor with deadband are thus well approximated. The describing function method is applied to linearise the backlash non‐linearity. Then a first‐order model of governor system is derived to consider the deadband effect quantitatively. Minimum frequency estimation algorithm is proposed based on the first‐order model. The proposed algorithm is effective to reflect the effects of various widths of deadbannd on the minimum value of frequency. Case study is conducted to prove its adequate performance in minimum frequency estimation with a practical power grid in China.

Keywords

• minimum frequency estimation algorithm
• power system
• governor deadbands
• strong deadband nonlinearity
• frequency response
• backlash nonlinearity