MCDGV4 Full Generator Protection with Block Differential

The generator differential protection relay MCDGV4 is a high precision protection for medium and high power generators. The step-up transformer can be integrated into the protection zone (unit protection/ block protection). In addition to the phase and earth differential protection, the device provides a variety of generator-specific protection functions. The “all-inclusive” package comprises also phase, earth current, voltage, frequency and power protection. In addition to that the device offers an undervoltage directional reactive power protection with reconnection function and an adjustable Fault Ride Through (FRT) with AR detection. The intuitive operating concept with plausibility checks and extensive commissioning functions such as the built-in fault simulator allows a safe and time-optimized maintenance and commissioning. The parameter setting and evaluation software Smart view SE can be used consistently across the entire family of devices.


Protection Functions   ANSI
Generator differential protection, Id>, Id>> 87G
Generator- and step-up transformer differential protection (block/unit protection) 87GT
Restricted earth fault IdE>, IdE>> 64REF / 87N
I, time overcurrent and short circuit protection, all elements can be configured for          directional or non-directional supervision. Multiple reset options
(instantaneous, definite time, reset characteristics according to IEC and ANSI).              Voltage controlled overcurrent protection by means of adaptive parameters                    Voltage dependent overcurrent protection
Negative phase sequence overcurrent protection
50P, 51P, 67P                  51C                                  51V
I2>, unbalanced load protection with evaluation of the negative phase sequence currents 46
Generator unbalanced 46G
Overload protection with thermal replica and separate pick-up values for alarm and trip functions 49
IH2/In, inrush detection with evaluation of the 2nd harmonic Inrush
IG, earth overcurrent and short circuit protection, all elements can be configured for      directional (multi-polarising) or non-directional supervision. Tremendous reset options  (instantaneous, definite time, reset characteristics according to IEC and ANSI). 50N/G, 51N/G, 67N/G
IE, sensitive earth overcurrent- and short circuit trip, all steps directional or non-directional 50Ns, 51Ns, 67Ns
V<, V>, V(t)<, under- and overvoltage protection, time dependent undervoltage protection 27, 59
Voltage asymmetry supervision (V012)
V1, under and overvoltage in positive phase sequence system                                        V2, overvoltage in negative phase sequence system
Each of the six frequency protection elements can be used as: f<  fs, df, dt, ROCOF, DF/DT, vector surge, ... 81U/O, 81R, 78
VX, residual voltage protection or bus bar voltage for synch check                                   or 100% - stator ground fault via evaluation of third harmonic 27TN / 27A / 59A / 59N
Phase distance (backup) protection 21P
Power swing blocking 68
Load blinder  
Out of step tripping (pole-slip protection) 78
ExP, external alarm and trip functions  
PQS, Power protection 32, 37
PF, Power factor 55
FRT (Fault Ride Through Including controlled by AR-feature) 27 (t, AR)
Q(V) Protection (undervolt. dep. directional reactive power protection with reclosing disengaging)  
10-Minutes-Mean-Square-Sliding Supervision: adjustable according to VDE-AR 4105  
Synch check 25
Volts / Hertz 24
Loss of field (excitation) 40
Inadvertent energization 50/27
Supervision Functions ANSI
CBF, circuit breaker failure protection 50BF
TCS, trip circuit supervision 74TC
LOP, loss of potential 60FL
FF, fuse failure protection via digital input 60FL
CTS, current transformer supervision 60L
CLPU, cold load pickup  
SOTF, switch onto fault  
THD supervision  
Breaker wear with programmable wear curves  
Recorders: Disturbance recorder, fault recorder, event recorder, trend recorder