A Coordinated Control Scheme for Fast Frequency Regulation of Thermal Power Units Based on Flexibility Transformation

doi:10.16183/j.cnki.jsjtu.2023.602

Abstract

Abstract:

With the popularization of renewable energy in the power system, improving the primary frequency regulation capability of thermal power units to suppress grid frequency fluctuations is currently a difficult problem to solve. However, the flexibility transformation of thermal power plants plays an important role in ensuring the safe and stable operation of the power grid. Traditional thermal units use coordinated control system (CCS) and digital electro-hydraulic control systems (DEH). With the transformation of condensate throttling (CT) and high-pressure heaters’ feedwater bypass (HPHFB), the fast frequency regulation characteristics of thermal units can also be improved. Therefore, in this paper, a new frequency regulation strategy is proposed by combining CCS, DEH, CT, and HPHFB. Additionally, gravitational search algorithm and fuzzy gain scheduling control strategy are combined to suit multiple operating conditions of thermal units to improve the fast frequency regulation performance of thermal units. The simulation results verify the effectiveness of the improved control strategy.

Key words: primary frequency regulation (PFR), operational flexibility, gravitational search algorithm (GSA), fuzzy gain scheduling

CLC Number:

TM611

ZHANG Jianhua, YAO Yi, ZHAO Si, WANG Yongyue. A Coordinated Control Scheme for Fast Frequency Regulation of Thermal Power Units Based on Flexibility Transformation[J]. Journal of Shanghai Jiao Tong University, 2025, 59(11): 1694-1706.

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参数名称	取值
p_T/MPa	25
额定主蒸汽温度/℃	600
额定再热蒸汽温度/℃	600
再热蒸汽压力/MPa	4.27
额定功率/MW	600
额定转速/(r·min^-1)	3000
额定主蒸汽流量/(kg·s^-1)	763
改造前机组爬坡速率/(MW·min^-1)	6~9

参数	取值
N_pop	20
迭代次数K	15
c₁	2
c₂	2
α	3
G₀	2
优化参数个数N_opt	6
粒子寻优上限p_pop,max	[20 5 0.3 10 20 0.12]
粒子寻优下限p_pop,min	[0 0 0 0 0 0]
寻优速度上限v_max	[1 0.1 0.01 0.1 1 0.01]
寻优速度下限v_min	[-1-0.1-0.01-0.1-1-0.01]
采样时间T_s	0.1

工况	CT				HPHFB
工况	K_p1	T_i	传递函数	限幅	K_p2	T_d	传递函数	限幅
30%	17.9070	1.0048	$\frac{17.907 0(s+0.9952)}{s}$	[0 0.2474]	8.2265	22.2861	8.2265+183.3366s	[0 0.1186]
50%	17.9011	23.3645	$\frac{17.9011(s+0.0428)}{s}$	[0 0.2164]	9.0870	19.5889	9.0870+178.0043s	[0 0.1082]
75%	17.5499	49.7512	$\frac{17.5499(s+0.0201)}{s}$	[0 0.2191]	9.0453	19.7207	9.0453+178.3796s	[0 0.1184]
90%	17.3488	11.5207	$\frac{17.3488(s+0.0868)}{s}$	[0 0.2128]	9.9425	19.9296	9.9425+198.1500s	[0 0.1196]

$\overline{N}$	a₁	a₂	a₃	a₄
B	B	S	S	S
L	S	B	S	S
M	S	S	B	S
H	S	S	S	B