Siemens 7SC80 Manual page 195

Overvoltage Protection - Positive Sequence System V1
In a three-phase voltage transformer connection the positive sequence system can be evaluated for the over-
voltage protection by means of configuring parameter 614 OP. QUANTITY 59 to V1. In this case, the
threshold values of the overvoltage protection must be set in parameters 5019 59-1 PICKUP V1 or 5020
59-2 PICKUP V1.
Dropout Threshold of the Overvoltage Protection
The dropout thresholds of the 59-1 element and the 59-2 element can be configured via the dropout ratio r =
V /V at addresses 5017 59-1 DOUT RATIO or 5018 59-2 DOUT RATIO. The following marginal
Dropout Pickup
condition applies to r:
r · (configured pickup threshold) ≤ 150 V with connection of phase-to-phase voltages and phase-to-ground
voltages or
r · (configured pickup threshold) ≤ 260 V with calculation of the measured values from the connected voltages
(e.g. phase-to-phase voltages calculated from the connected phase-to-ground voltages).
The minimum hysteresis is 0.6 V.
Phase-specific Pickup Voltages Overvoltage Protection
The phase-specific pickup voltages of the two overvoltage protection elements are set at the following
addresses:
59-1 PhA Pickup
59-1 PhB Pickup
59-1 PhC Pickup
59-2 PhA Pickup
59-2 PhB Pickup
59-2 PhC Pickup
The settable voltage range depends on the type of connection of either phase-to-phase voltage or phase-to-
ground voltage (parameter 213). For phase-to-phase connection, phase 1 corresponds to the connection A-B,
phase 2 B-C, and phase 3 corresponds to the connection C-A.
Phase-specific Time Delays Overvoltage Protection
The phase-specific times for tripping delay of the two overvoltage protection elements are set at the following
addresses:
59-1 PhA Delay
59-1 PhB Delay
59-1 PhC Delay
59-2 PhA Delay
59-2 PhB Delay
59-2 PhC Delay
Undervoltage Protection - Positive Sequence System V1
The positive sequence component (V1) can be evaluated for the undervoltage protection. Especially in case of
stability problems, their acquisition is advantageous because the positive sequence system is relevant for the
limit of the stable energy transmission. Concerning the pickup values there are no specific notes on how to set
them. However, because the undervoltage protection function is primarily intended to protect induction
machines from voltage dips and to prevent stability problems, the pickup values will usually be between 60 %
and 85 % of the nominal voltage.
The threshold value is multiplied as positive sequence voltage and set to √3, thus realizing the reference to the
nominal voltage.
Undervoltage protection comprises two elements. The pickup value of the lower threshold is set at address
5110 or 5111, 27-2 PICKUP (depending on the voltage transformer connection, phase-to-ground or phase-
to-phase), while time delay is set at address 5112, 27-2 DELAY (short time delay). The pickup value of the
SIPROTEC Compact, 7SC80, Manual
E50417-G1140-C486-A8, Edition 07.2017
Address 5030 or 5031
Address 5032 or 5033
Address 5034 or 5035
Address 5036 or 5037
Address 5038 or 5039
Address 5040 or 5041
Address 5042
Address 5043
Address 5044
Address 5045
Address 5046
Address 5047
Functions
2.6 Voltage Protection 27, 59
195