Non-Protection Features - GE MiCOM P40 Agile Technical Manual

P44x/EN AP/Hb6
(AP) 5-8
element can be used for SOFT/TOR logic. The fourth element can be configured for
stub bus protection in 1½ circuit breaker arrangements.
• 50N/51N: Instantaneous and time-delayed neutral overcurrent protection. Four
elements are available.
• 67N: Directional earth fault protection (DEF) - This can be configured for channel
aided protection, plus two elements are available for backup DEF.
• 67 / 46: Directional or non-directional negative sequence overcurrent protection - This
element can provide backup protection for many unbalanced fault conditions.
• 32N: Maximum of Residual Power Protection - Zero sequence Power Protection This
element provides protection against high resistance faults, cleared without using a
communications channel.
• 27 / 59: Undervoltage and overvoltage protections - Four-stage, configurable as either
phase to phase or phase to neutral measuring. Stage 1 may be selected as either
Inverse Definite Minimum Time (IDMT) or Definite Time (DT) and stage 2 is DT only.
• 37: Undercurrent Protection – this element consists of two independ stages protection,
with two independent time-delay setting.
• 81U / 81O: Underfrequency and overfrequency protection – This element can provides
a four-stage time-delayed underfrequency protection and two-stage time-delayed
overfrequency protection.
• 49: Thermal overload Protection - with dual time constant. This element provides
separate alarm and trip thresholds.
• 50 / 27: Switch on to fault (SOTF) and Trip On Reclose (TOR) protections - These
settings enhance the protection applied for manual circuit breaker closure.
• 78 / 68: Power swing blocking - Selective blocking of distance protection zones
ensures stability during the power swings experienced on sub-transmission and
transmission systems (stable swing or Out of Step condition = loss of synchronism).
The relay can differentiate between a stable power swing and a loss of synchronism
(out-of-step).
• 85: Channel Aided schemes with basic schemes, Permissive Underreach (PUP) and
Permissive Overreach (POP) transfer trip schemes and Blocking schemes.
• Weak infeed echo logic.
• Accelerated Trip features (Loss of Load – Zx extension).
• 46 BC: Broken conductor detection - To detect network faults such as open circuits,
where a conductor may be broken but not in contact with another conductor or the
earth.
• 50 BF: Circuit breaker failure protection - Generally set to backtrip upstream circuit
breakers, should the circuit breaker at the protected terminal fail to trip. Two stages
are provided.
• VTS: Voltage transformer supervision (VTS). - To detect VT fuse failures. This
prevents maloperation of voltage dependent protection on AC voltage input failure.
• CTS: Current transformer supervision - To raise an alarm should one or more of the
connections from the phase CTs become faulty.
• CVTS: Capacitive Voltage Transformer Supervision – to supervise voltage divider
capacitors supervision when residual voltage is greater than the set value.
1.2.2

Non-Protection Features

The P442 and P444 relays have the following non-protection features:
• 79/25: Autoreclosure with Check synchronism - This permits up to 4 reclose shots,
with voltage synchronism, differential voltage, live line/dead bus, and dead bus/live
line interlocking available. Check synchronism is optional.
• Measurements - Selected measurement values polled at the line/cable terminal,
available for display on the relay or accessed from the serial communications facility.
Application Notes
MiCOM P40 Agile P442, P444