Function Range or value Accuracy
*Trip time at 0 to 10 x Idunre,
unrestrained function
Min. = 5 ms
Max. = 15 ms
-
*Reset time at 10 x Idunre to 0,
unrestrained function
Min. = 15 ms
Max. = 35 ms
-
**Trip time, unrestrained negative
sequence function
Min. = 10 ms
Max. = 20 ms
-
**Reset time, unrestrained negative
sequence function
Min. = 10 ms
Max. = 30 ms
-
Critical impulse time 2 ms typically at 0 to 5 x IdMin -
*Note: Data obtained with single three-phase input current group. The operate and reset times for T2WPDIF/
T3WPDIF are valid for an static output from SOM.
**Note: Data obtained with two three-phase input current groups. The rated symmetrical currents are applied on
both sides as pre- and after-fault currents. The fault is performed by increasing one phase current to double on
one side and decreasing same phase current to zero on the other side.
6.2 High impedance differential protection, single phase
HZPDIF (87)
IP14239-1 v4
6.2.1 Identification
M14813-1 v4
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
High impedance differential
protection, single phase
HZPDIF
SYMBOL-CC V2 EN-US
87
6.2.2 Functionality
M13071-3 v13
High impedance differential protection, single phase (HZPDIF) (87) functions can be used when
the involved CTs have the same turns ratio and similar magnetizing characteristics. It utilizes an
external CT secondary current summation by wiring. Actually all CT secondary circuits which are
involved in the differential scheme are connected in parallel. External series resistor, and a voltage
dependent resistor which are both mounted externally to the IED, are also required.
The external resistor unit shall be ordered under IED accessories in the Product Guide.
HZPDIF (87) can be used to protect generator stator windings, tee-feeders or busbars, reactors,
motors, auto-transformers, capacitor banks and so on. One such function block is used for a high-
impedance restricted earth fault protection. Three such function blocks are used to form three-
phase, phase-segregated differential protection.
Section 6 1MRK 502 066-UUS B
Differential protection
144
Technical manual
To Next Page
Loading...
