Symbol

Meaning

Unit

ΔPmi

Conventional turbine mechanical power deviation

p.u.

ΔPwind

Wind turbine mechanical power deviation

p.u.

ΔPd

Disturbance power

p.u.

Δf

Deviation of system frequency

p.u.

PED

Instruction power

w

Tgi

Speed governor time constant

sec

Fri

Reheat time constant

sec

Tri

Turbine time constant

sec

D

Load-damping constant

-

K1

Integral gain of secondary frequency control

-

R1

Regulation coefficient of primary control

-

H

Inertia of generators and motors

-

s

Laplace operator

-