
Name
Unit
Range
Step
Description
Secondary reactive
current (PSC)
("Pos.Seq Reactive
Current Sec.")
A
-300.00…300.00 0.01
The secondary reactive current component measurement from
the positive sequence current channel.
Secondary residual
resistive current
("I0x Resistive Current
Sec.")
A
-300.00…300.00 0.01
The secondary resistive current component measurement from
both of the residual current channels.
Secondary residual
reactive current
("I0x Reactive Current
Sec.")
A
-300.00…300.00 0.01
The secondary reactive current component measurement from
both of the residual current channels.
5.2.2 Voltage measurement and scaling
The voltage measurement module (VT module, or VTM) is used for measuring the voltages from
voltage transformers. The measured values are processed into the measurement database and they
are used by measurement and protection functions (the protection function availability depends of the
relay type). It is essential to understand the concept of voltage measurements to be able to get correct
measurements.
Figure. 5.2.2 - 66. Voltage measurement terminology
PPRI:
RI: The primary voltage, i.e. the voltage in the primary circuit which is connected to the primary side of
the voltage transformer.
SEC:
SEC: The secondary voltage, i.e. the voltage which the voltage transformer transforms according to the
ratio. This voltage is measured by the protection relay.
For the measurements to be correct the user needs to ensure that the measurement signals are
connected to the correct inputs, that the voltage direction correct, and that the scaling is set correctly.
The relay calculates the scaling factors based on the set VT primary, and secondary voltage values.
The relay measures secondary voltages, which are the voltage outputs from the VT installed into the
application's primary circuit. The voltage can be measured directly from the system (up to 400 V) as
well. The rated primary and secondary voltages of the VT need to be set for the relay to "know"
the primary and per-unit values. In modern protection devices this scaling calculation is done internally
after the voltage transformer's primary and secondary voltages are set.
A
AQ
Q-F215
-F215
Instruction manual
Version: 2.04
71