In Germany the grid operator e.on and the Association of German network operators VDN demand that cogeneration sets connected to the HV system must not decouple in case of grid fault. There is a need to support the local voltage by the cogenaration sets (like windparks). Therfore the rules define two sets of voltage-time-characteristics.
The well known mains decoupling relay XRW will be available soon in a special version, which supprts these new characteristics. As the XRW notifies the specific fault level, it actually simplifies the implementation of the rules. It is your advantage that the decoupling command will be given much earlier in the case of fault compared to conventional undervoltage elements. This prevents your plant from a lot of unnecessary short circuit load.
With two characteristics you always know, if decoupling is permitted for short time or for long, compliant to the rules definition.
Protection elements of the XRW
· 2 undervoltage time characteristics with 5 selectable
definition points.
(presetted to the rules)
· 2 additional definite time voltage elements *
(e.g.Overvoltage and fault notification signal)
· 2 frequency elements *
· one ROCOF element for fast time decoupling in case of
unintended islanding.
* both elments can be freely assigned as “over” or “under”
function
It is worth to know, that the XRW is equipped with an extra
small reset hysteresis (<1%). This prevents your plant from
unintended off-periods caused by a grid voltage close to the
permitted limits. This often appears if e.g. windparks are
connected to the busbar of the local city station.
further fearures
· variants available for direct connection to
690-V-Windturbines-Systems
or 100-V-Station-VT
· Fault memory for analysis of fault reason
· serial interface for SCADA connection
· wide range power supply
· output “fault level” available
The XRW is the optimal protective relay, witch operates hand in
hand with your SCADA, your plant and your system.
Available now!
[1] Netzanschlusregeln Hoch und Höchstspannung, (NAR), e.on
Netz. Bayreuth, 1.August 2003
[2] EEG-Erzeugungsanlagen am Hoch und Höchstspannungsnetz,
16.6.2004, Verband der Netzbetreiber VDN e.V. Berlin,
[3] TransmissionCode 2003, Netz und Systemregeln der deutschen
Übertragungsnetzbetreiber, August 2003, Verband der
Netzbetreiber VDN e.V. Berlin
