Protection Relaying and Control System. The protective relaying system proposed to be provided for transmission lines, auto- transformers, reactors and bus bars to minimize the damage to the equipment in the events of faults and abnormal conditions, is dealt in this section. All main protective relays shall be numerical type with IEC 61850 communication interface and should have interoperability during integration of numerical relays to communicate over IEC61850 protocol with RTU/SAS/IEDs of different OEMs. All numerical relays shall have built in disturbance recording feature. The protection circuits and relays of transformer and reactor shall be electrically and physically segregated into two groups each being independent and capable of providing uninterrupted protection even in the event of one of the protection groups failing, to obtain redundancy, and to take protection systems out for maintenance while the equipment remains in service.
Protection Relaying and Control System. The protective relaying system proposed to be provided for transmission lines, auto- transformers, reactors and bus bars to minimize the damage to the equipment in the events of faults and abnormal conditions, is dealt in this section. All main protective relays shall be numerical type with IEC 61850 communication interface and should have interoperability during integration of numerical relays to communicate over IEC61850 protocol with RTU/SAS/IEDs of different OEMs. All numerical relays shall have built in disturbance recording feature. The protection circuits and relays of transformer and reactor shall be electrically and physically segregated into two groups each being independent and capable of providing uninterrupted protection even in the event of one of the protection groups failing, to obtain redundancy, and to take protection systems out for maintenance while the equipment remains in service.
a) Transmission Lines Protection
b) Auto Transformer Protection
i) Numerical Differential protection
ii) Numerical Restricted earth fault protection
iii) Numerical Back-up Over-current and earth fault protection on HV and IV side
iv) Numerical Over fluxing protection on HV and IV side
v) Numerical Overload alarm Further, Numerical Back-up Over-current and earth fault protection on HV and IV side of autotransformer shall not be combined with other protective functions in the main relays and shall be independent relays. Besides these, power transformers shall also be provided with Xxxxxxxx relay, Magnetic oil Gauge (MOG) with low oil level alarm, protection against high oil and winding temperature and pressure relief device etc. Suitable monitoring, control (operation of associated circuit breaker and isolator) and protection for LT auxiliary transformer connected to tertiary winding of auto-transformer for the purpose of auxiliary supply shall be provided. The over current and other necessary protection shall be provided for the auxiliary transformer. These protection and control may be provided as built in feature either in the bay controller to be provided for the auxiliary system or in the control and protection IEDs to be provided for autotransformer.
c) 765 kV and 400 kV Reactor Protection
i) Numerical Differential protection.
ii) Numerical Restricted earth fault protection
iii) Numerical Back-up impedance protection Besides these, reactors shall also be provided with Xxxxxxxx relay, Magnetic Oil Gauge (MOG) with low oil level alarm, protection against o...
