Function Supervision; Line Compensation - Siemens 6MD85 Manual

Siprotec 5 high-voltage bay controller

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Table of Contents

Control Functions

6.9 Voltage Controller

Function Supervision

Automatic Operation

If the actual voltage exceeds or falls below the set bandwidth for longer than the set time delay, this situation

is shown by the indication

range, the indication is reset. You can switch off the function monitor with a time delay = 0 min.

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Figure 6-128

When using line compensation, the voltage drop of a phase that is connected to a transformer can be

included. In this case, 2 processes are available:

Z compensation (LDC-Z)

X and R compensation (LDC-XandR)

Line compensation is only active if power is flowing in the direction of the line.

Z Compensation (LDC-Z)

Z compensation allows you to include the voltage drop of a line connected to the transformer. You can switch

Z compensation on or off. If cos φ is roughly constant, you can use Z compensation. Setting the parameters

requires the calculation of the voltage increase (Target voltage rising) taking into consideration the

load current (Max load current).

The parameter Target voltage rising represents the voltage drop across the line as a % under rated

You can find more information and the calculation in chapter

In case of active Z compensation, you must limit the maximum permitted voltage increase in relation to the

target voltage to avoid too high voltage at the transformer. To do this, set the parameter Max load

current. In addition, the parameter Vmax threshold is active. If the actual voltage exceeds this threshold

value, no more higher adjusting commands are issued.

(_:14011:309) Auto Monitor . If the actual voltage returns to the voltage

Logic of the Function Supervision for Automatic Operation

SIPROTEC 5, High-Voltage Bay Controller, Manual

C53000-G5040-C015-9, Edition 11.2017