Differential Protection - Hitachi Relion 670 Series Product Manual

Line differential protection RED670
Version 2.2
Table 10. Basic IED functions, continued
IEC 61850 or function Description
name
ALTMS Time master supervision
ALTIM Time management
CAMCONFIG Central account management configuration
CAMSTATUS Central account management status
TOOLINF Tools information
COMSTATUS Protocol diagnostic
Table 11. Local HMI functions
IEC 61850 or function Description
name
LHMICTRL Local HMI signals
LANGUAGE Local human machine language
SCREEN Local HMI Local human machine screen behavior
FNKEYTY1–FNKEYTY5 Parameter setting function for HMI in PCM600
FNKEYMD1–
FNKEYMD5
LEDGEN General LED indication part for LHMI
OPENCLOSE_LED LHMI LEDs for open and close keys
GRP1_LED1– Basic part for CP HW LED indication module
GRP1_LED15
GRP2_LED1–
GRP2_LED15
GRP3_LED1–
GRP3_LED15

4. Differential protection

High impedance differential protection, single phase
HZPDIF
High impedance differential protection, single phase
(HZPDIF) functions can be used when the involved CT
cores 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 can be used to protect 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.
32
Restricted earth-fault protection, low impedance
REFPDIF
M13071-3 v13
Restricted earth-fault protection, low-impedance function
(REFPDIF) can be used on all directly or low-impedance
earthed windings. The REFPDIF function provides high
sensitivity and high speed tripping as it protects each
winding separately and thus does not need inrush
stabilization.
The REFPDIF function is a percentage biased function with
an additional zero sequence current directional comparison
criterion. This gives excellent sensitivity and stability during
through faults.
REFPDIF can also protect autotransformers. Five currents
are measured at the most complicated configuration as
shown in Figure 5.
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M13047-3 v20
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