Active and reactive power coordinated secondary control based on control sensitivity in microgrids

doi:10.3969/j.issn.2097-0706.2024.02.005

Abstract

Abstract:

The values of resistance and reactance of lines in the microgrid of medium and low voltage levels are quite close，leading to weak decoupling of active and reactive power during power flow control. If the secondary control on microgrid operates in line with the control method of a bulk power system which adjusts active power and reactive power independently, there will be overshoots and oscillations. To solve this problem, a secondary control method based on control sensitivity is proposed for of active and reactive power coordinated control in microgrids. Firstly, the calculation formula of control sensitivity for secondary control is derived according to the primary control processes of different types of microgrids. Then, based on the control sensitivity, a quadratic programming model is established, aiming at minimizing the deviations of frequency and voltage and coordinated secondary control on active and reactive power. The adjustments of the secondary control are obtained by solving this model. Taking an islanded microgrid as the example, it is proved that the proposed method can improve the accuracy and stability of the secondary control in microgrid, comparing with the secondary control with independent adjustment of active and reactive power.

Key words: microgrid, secondary control, coordinated control, control sensitivity, quadratic programming

CLC Number:

TK01：TM743

GONG Wei, SUN Dan, LI Yiyuan. Active and reactive power coordinated secondary control based on control sensitivity in microgrids[J]. Integrated Intelligent Energy, 2024, 46(2): 36-42.

Figures/Tables 10

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元件	电阻/Ω	电抗/Ω	变比
线路1	0.176	0.143
线路2	0.583	0.473
线路3	1.419	1.155
线路4	0.352	0.286
变压器1	1.133	4.950	380 V/10 kV
变压器2	1.133	4.950	380 V/10 kV

节点名	节点类型	节点注入有功/MW	节点注入无功/（MV·A）	参考电压（标幺值）	参考相角/rad
母线1	PQ节点	0	0	—	—
母线2	平衡节点	—	—	1.02	0
母线3	PQ节点	-0.6	-0.2	—	—
母线4	PQ节点	-0.8	-0.2	—	—
母线5	PQ节点	0	0	—	—
母线6	PQ节点	0.5	0.1	—	—
母线7	PQ节点	0.7	0.1	—	—

微源	有功上限/MW	有功下限/MW	无功上限/（MV·A）	无功下限/（MV·A）
柴油发电机	2.0	1.0	0.5	-0.5
储能单元	0.8	-0.8	0.2	-0.2
风力发电机	1.0	0.0	0.3	-0.3

状态变量	控制变量
状态变量	V_d	P_s	Q_s	P_w	Q_w
P_d	0.024 8	0.981 7	0.000 1	0.973 9	0.000 2
Q_d	0.069 6	0.048 4	0.994 5	0.067 8	0.995 1
V₁	1.000 8	0.001 5	0.001 3	0.001 4	0.001 3
V₃	1.004 7	0.001 5	0.001 3	0.001 4	0.001 3
V₄	0.997 2	0.013 4	0.011 4	0.013 1	0.011 4
V₅	0.995 0	0.013 4	0.011 4	0.016 0	0.013 9
V₆	0.988 8	0.022 3	0.054 7	0.013 0	0.011 3
V₇	0.985 5	0.013 3	0.011 3	0.024 4	0.057 0

状态变量	控制变量
状态变量	P_0d	Q_0d	P_0s	Q_0s	P_0w	Q_0w
f	0.016 9	0.000 0	0.016 6	0.000 0	0.016 5	0.000 0
V₁	0.005 9	0.026 7	0.002 5	0.012 0	0.003 5	0.011 7
V₂	0.006 8	0.027 3	0.002 9	0.011 7	0.003 9	0.011 4
V₃	0.005 9	0.026 8	0.002 5	0.012 1	0.003 5	0.011 8
V₄	0.001 1	0.021 9	0.001 2	0.014 4	0.000 0	0.014 0
V₅	0.002 0	0.021 3	0.000 3	0.014 0	0.001 7	0.014 9
V₆	0.002 2	0.011 6	0.003 8	0.030 9	0.001 6	0.007 4
V₇	0.002 6	0.011 3	0.001 4	0.007 4	0.004 0	0.031 1