Megacon - the trendsetter in synchronisation control for paralelling or phasing of AC supplies
Today Megacon uses the following two basic synchronisation control principles:
SYSTEM "S" - SECTOR SYNCHRONISATION
Bi-directional Check Synchronising Relay
system "S" guard is a low-differential Check Synchronising Relay.
Synchronising relay closes when phase differential is within set limits
(sector "S") for a pre-set time ("t").
Sector synchronisation is the
classical alternative for applications which allows that
synchronisation accuracy and speed of synchronisation are interrelated.
Synchronisation accuracy (Df) can be calculated by following formula:
Df = S : 360 x t
i.e. set sector (S) to 10° and retention time (t) to 0.5 sec to obtain an accuracy (Df ) of 0.05 Hz.
SYSTEM "P" - "SPOT-ON" SYNCHRONISATION
Uni-directional Fast and Accurate Synchronisation
dynamically controlled system "P" provides the fastest "spot-on"
synchronisation. Dynamic breaker closing time compensation assures
precision 12 o’clock synchronisation, when frequency of incoming
generator is slightly higher than busbar frequency.
initiates generator breaker closure at moment "T", angle "a" is
dynamically adjusted according the two systems frequency/phase
This directional synchronisation relay allows
operation when frequency of incomer is HIGHER than bus frequency. In
this way incomer is protected against motoric operation during start-up.
To adapt the functionality of KSQ104F to any specific application, the
direction of approach to synchronising (LEAD, LAG or NEUTRAL) can be
selected as required:
- LEAD (incomer faster than bus)
- LAG (incomer slower than bus)
- NEUTRAL (bi-directional)
LEAD is generally the preferred mode. The synchronising relay will then
operate when the frequency of the incomer is slightly HIGHER than the
bus frequency. This is to avoid motoring of the incomer (entering
reverse power condition) after the breaker is closed.