Changyuan Shenru ISA-351G Line Protection and Control Device

ISA-351G is an integrated feeder protection and control device that implements protection, measurement and control, and operation functions for feeders, transformer groups, and sections.
Protection Functions
1) Phase current over-limit recording element with independent threshold
2) Three-stage current protection that can be independently enabled or disabled
3) Inverse-time overcurrent protection with selectable extreme, very, or general operating characteristics
4) Phase current acceleration protection with selectable pre-acceleration or post-acceleration
5) Selectable three-phase primary/secondary automatic reclosing (with optional synchronization check and dead voltage check)
6) Under-frequency load shedding with slip/no-slip blocking
7) Under-voltage load shedding with voltage slip blocking
8) Zero-sequence overcurrent protection with zero-sequence direction, compatible with different grounding methods
9) Overload protection
10) Control circuit break alarm with optional reclosing blocking function
11) Bus PT break alarm with optional blocking of voltage-related protections
12) External input protection with settable delay that can be enabled or disabled
13) Independent operating circuit and fault recording
14) Remote ground fault line selection test trip function for ungrounded systems (automatic identification of line grounding)
15) Blocking of simplified bus protection

Measurement and Control Functions:
1) 3 position remote signals collected via the operating circuit; 8 (expandable to 20) remote signal inputs, with options for blocking reclosing, external trip input, external alarm input, external reset, and device maintenance; multiple soft remote signals, including general fault signal, reclosing charging flag, and protection soft壓板
2) 21 remote measurements: Ia, Ib, Ic, Ua, Ub, Uc, 3I0, Uab, Ubc, Uca, 3U0, Pa, Pb, Q, S, φ, Fr, 3I01, 3I05
3) Remote control of switches and soft壓板, with recording and statistics of remote control operations
4) Large-capacity event recording, SOE recording, self-check recording, and instantaneous protection blocking recording
5) Harmonic analysis function up to the 11th order
6) Remote control function with interlock rules consistent with the five-prevention host