• The fast "Spot-on" synchroniser
• LEAD and/or LAG synchronising facility
• Breaker closing time compensation
• Dead-bus facility
• "Easy view" status presentation
• Generator speed control (relays)
• Generator speed reference (analogue output)
• Systemstatus output

Description
The digitally controlled KCQ104EJD42 provides both visual presentation of voltage differential and relative speed and phase angle relationship and speed control output signals necessary to achieve fast automatic "spot-on" synchronising between two systems. When used as dead-bus coupler the CB close relay will energise when bus is "dead" and the digital input (dead-bus enable) is closed (mode 4 to 6).

Its many important features contribute to make KCQ104EJD42 simply the best choice available for synchronising in any automatic generator control system (PM-system).

KCQ104EJD42 comes with separate auxiliary supply on terminal 19 & 20.

Applications
KCQ104EJD42 is used for both single and three phase systems. Any two phases (or phase-neutral) can be used for synchronising as long as they are the same two phases on both sides of the breaker. The synchroniser is rated for continuous operation and can be left connected when not in use.

Synchronising modes
To adapt the functionality of KCQ104EJD42 to any specific application, the direction of approach to synchronising  (LEAD, LAG or NEUTRAL) can be selected as required:
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.

Speed control
The raise/lower relays pulses the fuel control governor motor, or an interfacing MXR845x electronic potentiometer. Pulse length and rate of the speed control relays are adjusted on the rear of the unit to suit the dynamic response of any engine regulator. The speed control has a P/I (proportional/integral) characteristic, with a dynamically controlled dead zone.

Alternatively the linear analogue -10/0/+10mA output signal can be used as speed reference to a generator controller, with polarity and amplitude proportional to frequency difference between the two systems when synchronising mode is selected.

System status:
KCQ104EJD42 is fitted with a system status relay. When power is ok and unit is working correctly the relay activates. It will release on alarm or when unit is not powered.
Normal operation                : Closed contact
Alarm condition/unpowered  : Open contact

"SPOT ON" synchronisation  -  CB closing time compensation
The dynamically controlled CB closing time compensation provides SMOOTH synchronising, avoiding the engine/generator couplings being exposed to excessive torque forces. If FAST synchronisation is the priority, accurate "SPOT-ON" synchronising will still be maintained even with a large frequency difference between the power sources.

The System "P" synchronising principle
The relay closure is initiated at "T" when the breaker coil is energised and finalises at "P", assuring a precise "12 o'clock" synchronisation (figs 1 and 2). Allowed frequency difference is adjustable between 0.1Hz and 2Hz.

Typical setting for smooth synchronising is 0,2Hz. The angle "a" varies according to the calculated frequency difference between the two systems. The synchroniser operation and accuracy is not influenced by distorted voltage waveforms or harmonics.

Synchronisation
Green lamps indicate voltage presence on reference source (BUS PWR, only when generator is powered) and incoming generator (GEN PWR). Green lamps also indicate that voltage and frequency differential between the two systems are within the limits. The synchronising relay will close when above conditions are achieved.

A green lamp (CB close) indicates the closing command to the breaker. Frequency difference and voltage limits, circuit breaker closing time, speed control relays pulse length/rate and synchronising mode are user settable on unit rear.

Note: The CB Close LED will flash when unit is ready for synchronising, but inhibit input is open or synchronising mode is not selected.