ISA-367G Line Protection and Control Device

The ISA-367G is an integrated line protection and control device that provides protection, measurement, control, and operation functions for transmission lines.
Basic Configuration
Protection Functions:
1. Phase current over-limit recording element with independent threshold
2. Three-stage undervoltage-locked directional overcurrent protection (directional element and undervoltage element can be set independently) with independent enable/disable capability
3. Undervoltage-locked phase current post-acceleration protection
4. Three-phase single-shot auto-reclosing (with optional synchronization check, dead-line check, and overcurrent lockout functions)
5. Underfrequency load shedding with slip frequency lockout
6. Undervoltage load shedding with voltage slip lockout
7. Zero-sequence directional overcurrent protection for ungrounded systems
8. Overload protection
9. Control circuit break alarm with optional reclosing lockout function
10. Bus PT break alarm (optionally blocking voltage-related protections) and line PT break alarm (optionally blocking auto-reclosing)
11. Independent operating circuit and fault recording
Measurement and Control Functions:
1. 3 position status signals collected via the operating circuit
2. 8 status input channels, configurable for reclosing lockout, external trip input, external alarm input, external reset, and maintenance input
3. Multiple software status signals, including general fault signal, reclosing ready flag, and protection soft switch status
4. 19 telemetry measurements: Ia, Ib, Ic, Ua, Ub, Uc, 3I0, Uab, Ubc, Uca, 3U0, Pa, Pb, Q, S, φ, Fr
5. Remote control of switches and soft switches, with operation logging and statistics
6. Large-capacity event recording, SOE recording, self-check recording, and instantaneous protection lockout recording
7. Harmonic analysis up to the 11th order
8. Bay-level interlocking remote control function with rules consistent with the five-prevention host
Other Functions: Optional voltage switching module
2 Protection Principles
1 Phase Current Over-limit Recording Element
The phase current over-limit recording element has an independent over-limit threshold setting d797 and records the over-limit condition of each phase separately, generating independent phase current over-limit records including the start time, duration, and maximum current of each phase's over-limit event.
1) Per-phase recording facilitates detailed and comprehensive disturbance analysis.
2) This record is not used for alarms but solely for disturbance analysis.
3) The device interface provides a function to view phase current over-limit records.
4) The setting of d797 should be above the maximum load current (to avoid unnecessary frequent recording) while ensuring sufficient sensitivity for minimum fault currents.