CT

Current Transformer

CVT

Capacitive Voltage Transformer

VT

Voltage Transformer

AIS

Air-insulated Switchgear

GIS

Gas-Insulated Switchgear

K

actual transformation ratio

k_r

rated transformation ratio

ε

ratio error

△φ

phase displacement

S_r

rated output

U_sys

highest voltage for system

U_m

highest voltage for equipment

f_R

rated frequency

F

mechanical load