Characteristics Analysis and Fuzzy Fractional-Order PID Parameter Optimization for Primary Frequency Modulation of a Pumped Storage Unit Based on a Multi-Objective Gravitational Search Algorithm

Xin Wu,Jianzhong Zhou,Yanhe Xu,Cong Lv,Jie Liu,Qing Zhang

doi:10.3390/en13010137

Abstract

Compared with conventional hydropower units, the pumped storage unit has the characteristics of diverse working conditions and frequent switching. Therefore, the stability and regulation quality of the primary frequency modulation transition process of the regulating system is very important. Due to the “S” characteristics of the pumped storage unit (PSU), the pumped storage unit regulating system has a strong nonlinearity, and the conventional proportional-integral-derivative (PID) controller cannot provide high-quality control under low water head conditions. In this paper, the nonlinear PSU model with an elastic water hammer effect is studied, and the fuzzy fractional-order PID (FFOPID) controller is designed to improve the stability of the system. The membership function and the control parameters of the fractional-order PID are optimized based on the multi-objective gravitational search algorithm (MOGSA). The experimental results show that the optimized design of the FFOPID controller has better control quality than the traditional PID controller, the fractional-order PID (FOPID) controller, and the fuzzy PID controller (FPID) when the system is disturbed by the rotating speed under low water head.

Highlights

With the constant cost of traditional energy sources and the increasing pollution of the environment, the use of renewable energy has received extensive attention
In order to show that the fuzzy fractional-order PID (FFOPID) controller has a better control effect than the traditional controller, they were successively put into the multiple simulation experiments for comparison
The results show that the oscillation amplitude of the water hammer in the surge chamber obtained by the FFOPID controller is smaller than that obtained by other

Summary

Introduction

With the constant cost of traditional energy sources and the increasing pollution of the environment, the use of renewable energy has received extensive attention. With the formation of regional power grids, equipment fault diagnosis and the primary frequency modulation of the pumped storage unit regulating system has played a vital role in the safe and stable operation of the power system [3,4,5,6]. In previous primary frequency modulation studies, the modeling of PSU usually adopts the simplified linear model and the water diversion system model is based on the rigid water hammer theory [7,8]. The impact of elastic water hammer on pipeline must be considered for the pumped storage unit regulating system with a long water diversion system [10]. It is necessary to establish a Energies 2020, 13, 137; doi:10.3390/en13010137 www.mdpi.com/journal/energies

Methods

Results

Conclusion