14.2. Objective.
14.3. General Principles.
(1) No item of electrical equipment shall be allowed to remain connected to the State Transmission System unless it is covered by minimum specified protection aimed at reliability, selectivity, speed, stability and sensitivity.
(2) All Users shall co-operate with STU to ensure correct and appropriate settings of protection to achieve effective, discriminatory removal of faulty equipment within the target clearance time specified in this Section.
(3) Protective Relay settings shall not be altered, or protection relays bye-passed and/or disconnected without consultation and agreement between all affected Users. In a case where protection is bye-passed and/or disconnected by an agreement, then the cause must be rectified and the protection restored to normal condition as quickly as possible. If agreement has not been reached, the electrical equipment shall be removed from service forthwith.
14.4. Protection Coordination.
14.5. Fault Clearance Times & Short-time Ratings.
Nominal Voltage
Minimum Short Circuit current rating &
duration for Switchgear
Target Fault clearance Time
KV
KA(rms)
Seconds
msec.
220 KV
40
1
160
132 KV
40
1
160
14.6. Generator Requirements.
14.7. Transmission Line Requirements.
Main 1
Main 2
• A single scheme three zone, non-switched numeric distance protection with standard built in features like single and three phase tripping, carrier inter-tripping, IDMT over current and earth fault, power swing blocking and LBB protection shall be provided as main protection.
• The backup protection shall be at least two directional IDMTL over current relays and one directional earth fault relay.
• For short transmission radial lines, appropriate alternative protection schemes may be adopted.
• For 33 KV feeders, emanating from Grid S/S, adequate protection with proper co-ordination should be provided at Grid S/S.
14.8. Transformer Requirements.
i. All 220 KV class power transformers shall be provided with numeric fast acting differential, REF, open delta (Neutral Displacement Relay) and over-fluxing relays. In addition, there shall be back up IDMTL over current and earth fault protection with directional features. For parallel operation, such back up protection shall have inter-tripping of both HV and LV breakers. For protection against heavy short circuits, the over current relays should incorporate a high set instantaneous element. In addition to electrical protection, transformer own protection viz. Buchholz, OLTC oil surge, gas operated relays, winding temperature protection, oil temperature protection, PRV relay shall be provided for alarm and trip functions.
ii. For 132 KV and 33 KV class transformers of capacity 10 MVA and above, the protection shall be same as mentioned in 14.8 (1) (i) except over-fluxing, REF and PRV relays.
iii. For 132 KV and 33 KV class power transformers less than or equal to 10 MVA provided on either Transmission or Distribution System, over current and E/F with high set instantaneous element along with auxiliary relays for transformer trip and alarm functions as per transformer requirements, shall be provided.
14.9. Sub-Station Fire Protection.
14.10. Calibration and Testing.
Section 14 • Bihar Electricity Grid Code, 2010
14. Protection.
bihar-electricity-grid-code-2010-sec-14.json
•
Section 14
{
"act_title": "Bihar Electricity Grid Code, 2010",
"act_slug": "bihar-electricity-grid-code-2010",
"section_label": "Section",
"section": {
"number": "14",
"title": "14. Protection.",
"chapter": null,
"content": "14.2. Objective.\n14.3. General Principles.\n(1) No item of electrical equipment shall be allowed to remain connected to the State Transmission System unless it is covered by minimum specified protection aimed at reliability, selectivity, speed, stability and sensitivity.\n(2) All Users shall co-operate with STU to ensure correct and appropriate settings of protection to achieve effective, discriminatory removal of faulty equipment within the target clearance time specified in this Section.\n(3) Protective Relay settings shall not be altered, or protection relays bye-passed and/or disconnected without consultation and agreement between all affected Users. In a case where protection is bye-passed and/or disconnected by an agreement, then the cause must be rectified and the protection restored to normal condition as quickly as possible. If agreement has not been reached, the electrical equipment shall be removed from service forthwith.\n14.4. Protection Coordination.\n14.5. Fault Clearance Times & Short-time Ratings.\nNominal Voltage\nMinimum Short Circuit current rating &\n\t\t\t\tduration for Switchgear\nTarget Fault clearance Time\nKV\nKA(rms)\nSeconds\nmsec.\n220 KV\n40\n1\n160\n132 KV\n40\n1\n160\n14.6. Generator Requirements.\n14.7. Transmission Line Requirements.\nMain 1\nMain 2\n• A single scheme three zone, non-switched numeric distance protection with standard built in features like single and three phase tripping, carrier inter-tripping, IDMT over current and earth fault, power swing blocking and LBB protection shall be provided as main protection.\n• The backup protection shall be at least two directional IDMTL over current relays and one directional earth fault relay.\n• For short transmission radial lines, appropriate alternative protection schemes may be adopted.\n• For 33 KV feeders, emanating from Grid S/S, adequate protection with proper co-ordination should be provided at Grid S/S.\n14.8. Transformer Requirements.\ni. All 220 KV class power transformers shall be provided with numeric fast acting differential, REF, open delta (Neutral Displacement Relay) and over-fluxing relays. In addition, there shall be back up IDMTL over current and earth fault protection with directional features. For parallel operation, such back up protection shall have inter-tripping of both HV and LV breakers. For protection against heavy short circuits, the over current relays should incorporate a high set instantaneous element. In addition to electrical protection, transformer own protection viz. Buchholz, OLTC oil surge, gas operated relays, winding temperature protection, oil temperature protection, PRV relay shall be provided for alarm and trip functions.\nii. For 132 KV and 33 KV class transformers of capacity 10 MVA and above, the protection shall be same as mentioned in 14.8 (1) (i) except over-fluxing, REF and PRV relays.\niii. For 132 KV and 33 KV class power transformers less than or equal to 10 MVA provided on either Transmission or Distribution System, over current and E/F with high set instantaneous element along with auxiliary relays for transformer trip and alarm functions as per transformer requirements, shall be provided.\n14.9. Sub-Station Fire Protection.\n14.10. Calibration and Testing.",
"footnote": "",
"is_definition": false,
"sort_order": 38
},
"prev_section": "38",
"next_section": "40"
}