Woodward HighPROtec MCDLV4, Manual

Page: 903 / 1275

Protective Elements
Q->&V< Reactive-Power/Undervoltage Protection
Available Elements:
Q->&V<
The number of distributed energy resources (DER) raises continuously. At the same time the controllable power
reserve through large-scale power plants decreases.
Therefore various grid codes requirements and regulations stipulate that mains parallel distributed power plants,
consisting of one or more power generation units feeding power into the MV grid, have to support the mains voltage
in case of failures.
In case of failure the voltage close to the short circuit location drops nearly to zero. Around the fault location a
potential gradient area is built whose expansion can be restricted by feeding reactive-power into the grid. At mains
failures (voltage drop) the Q->V< protection prevents the expansion of the potential gradient area for the case that
any further reactive-power is taken from the mains.
The function of this protection module is not the protection of the power generation system itself, but more the
decoupling of the power generation system when it takes reactive current from the mains in case the voltage drops
below a certain value. This protection is an upstream system protection.
The Q->&V< protection module is implemented as an autonomous protection element according to the German
regulations
1
and
2
mentioned below (for reconnection see separate element).
The comprehensive setting and configuration possibilities of this protection element allow the adaptation of
connected energy resources to various grid conditions.
For the correct function of this protection module you have to
Configure the »General Settings«,
Select and set the decoupling method.
Configure the reconnection of the power generation units (see chapter Reconnection).
General Settings
For each parameter set [Protection Para\Set [x]\Q->&U<] the general settings »General Settings« can be
configured.
Here the entire function of this protection element can be activated or deactivated.
By activating the voltage transformer supervision a malfunction of this protection module can be prevented.
1 Technische Anschlussregeln für die Hochspannung (VDE-AR-N 4120)
2 Technische Richtlinie „Erzeugungsanlagen am Mittelspannungsnetz“, Richtlinie für Anschluss und Parallelbetrieb von
Erzeugungsanlagen am Mittelspannungsnetz, Ausgabe Juni 2008, BDEW Bundesverband der Energie- und Wasserwirtschaft e.V., siehe Kap.
3.2.3.2 – Blindleistungs-Unterspannungsschutz Q->&U<
903 MCDLV4 DOK-HB-MCDLV4-2E