A Distributed AGC Method considering Two-Channel Random Delays and Their Difference between Interconnected Power Systems

Table 1

Notations of variables.

Variables	Notations	Units
Tgi	Time constant of the governor for area i	s
Tti	Time constant of the generator for area i	s
Kri	Reheat coefficient of the steam turbine for area i	p.u.
Tri	Reheat time constant for area i	s
Ri	Speed regulation parameter for area i	Hz/p.u.
Bi	Frequency bias factor for area i	p.u./Hz
Mi	Rotary inertia of assembling unit for area i	p.u.s^2
Di	Damping coefficient of load for area i	p.u./Hz
ΔPti	Change in turbine output for area i	p.u.
ΔPri	Change in thermal power output of reheat steam turbine generator sets for area i	p.u.
ΔXgi	Change in valve position of the governor for area i	p.u.
ΔPci	Control variable of controller for area i	p.u.
ΔPLi	Load changes for area i	p.u.
Δfi	Frequency deviation for area i	Hz
ΔPtij	Tie-line active power deviation	p.u.
Tij	Power system synchronizing coefficient	s
ACEi	Area control error for area i	p.u.
τi	Controller-to-actuator (C-A) delay	s
τij	Sensor-to-controller (S-C) delays among different areas	s
τca	Delay from controller to actuator	s
τsc	Delay from sensor to controller	s