ABB Relion 670 Series Technical Reference Manual page 498

Line differential protection ansi

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Voltage protection

function is blocked and no PICKUP or TRIP signal is generated.The time delay

characteristic is individually chosen for each step and can be either definite time delay

or inverse time delay.

UV2PTUV (27) can be set to measure phase-to-ground fundamental value, phase-to-

phase fundamental value, phase-to-ground true RMS value or phase-to-phase true

RMS value. The choice of the measuring is done by the parameter ConnType. The

voltage related settings are made in percent of base voltage which is set in kV phase-to-

phase voltage. This means operation for phase-to-ground voltage under:

EQUATION1606 V1 EN

and operation for phase-to-phase voltage under:

(%) VBase(kV)

EQUATION1991-ANSI V1 EN

When phase-to-ground voltage measurement is selected the function

automatically introduces division of the base value by the square root

Measurement principle

Depending on the set ConnType value, UV2PTUV (27) measures phase-to-ground or

phase-to-phase voltages and compare against set values, Pickup1 and Pickup2. The

parameters OpMode1 and OpMode2 influence the requirements to activate the

PICKUP outputs. Either 1 out of 3, 2 out of 3, or 3 out of 3 measured voltages have to

be lower than the corresponding set point to issue the corresponding PICKUP signal.

To avoid oscillations of the output PICKUP signal, a hysteresis has been included.

The time delay for the two steps can be either definite time delay (DT) or inverse time

undervoltage (TUV). For the inverse time delay three different modes are available:

inverse curve A

inverse curve B

customer programmable inverse curve

1MRK505222-UUS C

(Equation 117)

(Equation 118)

Technical reference manual

Relion red670