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.
FEATURES & FUNCTIONALITY
| 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 51Q |
| 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 |
47 |
| 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 |
