Page 309 - Decision Making Applications in Modern Power Systems

270 Decision Making Applications in Modern Power Systems

ΔP sch the scheduled power flow through tie-lines
tie;ij
ΔP act the actual power flow through tie-lines
tie;ij
incremental change in tie-line power (p.u.)
ΔP Tie,ij
load power change
ΔP L
mechanical power (p.u.)
ΔP m
R governor speed regulation parameter (Hz/p.u. MW)
R i up;t ; R i down;t the probabilistically worst case up down spinning reserves
R i t the power correction term
ST settling time (s)
t time (s)
T g governor time constant (s)
T ij synchronizing coefficient of tie-line (p.u.)
T ps power system time constant (s)
T R reheat system time constant (s)
T t turbine time constant (s)
t sim simulation time (s)
u c;i the control signal
λ the integral order
μ the derivative order
ϒ a set of the indices corresponding to outages of all components
the set of branch outage index
ϒ l
ϒ L the set of load outage index
ϒ G the set of generators outage index
AGC automatic generation control
AVR automatic voltage regulator
FOPID fractional-order PID
hGSA-PS hybrid gravitational search and pattern search algorithm
ICA imperialist competitive algorithm
LFC load-frequency control
OPF optimal power flow
PID proportional integral derivative
RERs renewable energy resources
SCADA supervisory control and data acquisition
SC-OPF security-constrained optimal power flow
TSO transmission system operator
WAMS wide-area measurement system
WDO wind driven optimization

11.1 Introduction

A large modern power system under deregulation consists of several inter-
connected control areas, where each one is responsible for supplying its
loads and keeping the scheduled power interchanges with its neighbor areas.
These responsibilities gradually become more difficult when moving toward
smart grid and deregulation concepts. Load-frequency control (LFC) is a
technique adopted in the power system control center to guarantee the bal-
ance between generation and demand and consequently to maintain the