ELECTRICAL POWER SYSTEM NOTES

IN THIS APPLICATION HAS THE FOLLOWING TOPICS

1. PROTECTION
- protective schemes
(i)core balanced protective schemes.
(ii) merz-price protective schemes.
(iii) pilot
(iv) pilot-less.
- types of relay systems
(i) permanent magnet moving coil.
(i) balanced beam
(ii) induction type carrying relay
(iv) the distance relay
(v)non-directional relay
(vi)solid state relay.

-types of unit protection

(i)generator protection
(ii) transformer protection
(iii) feeder protection

- non-unit protection
(i)directional current protection
(ii) distance protection
(iii) gradient time protection

2.OVERHEAD LINE CONSTRUCTION
- conductor/mechanical vibration

(i) swinging
(ii)dancing
(iii) jumping
(iv) high frequency vibration

- sag and tension
(i)ca-ternary method

-corona phenomenon
(i)disruptive
(ii)visible
(iii)critical
(iv)power loss

- operation of synchronous phase modifies
(i)lagging and leading
(ii)volt drop compensation


3. OVERHEAD LINE TRANSMISSION
- classification of transmission lines
(i)short, medium and long lines
- causes of surges in transmission line
(i)direct and indirect lighting stroke
(ii)open circuited lines
(iii)short circuited lines
(iv)an arching ground faults
--phenomenon surges explanation in transmission line
(i)surge velocity
(ii)surge impedance
(iii)open circuited and short circuited lines
--protection of transmission line against surges
(i)overhead earth wire
(ii)horn gaps
(iii)silicon and zinc oxides surge diverts
(iv)Peterson coil

4.UNSYMMETRICAL FAULTS
--types of power line faults
(i)single phase to ground fault (L - G)
(ii)3-phase faults (L - L -L)
(iii)double line to ground fault (L - L - G)
--description of symmetrical components
(i)positive, negative and zero sequence vector
(ii)Impendence connection matrices for fault
(iii)equivalent circuit for unsymmetrical fault
--operation of equivalent circuit and phase sequence matrix

5. POWER SYSTEM STABILITY
--synchronous generator stability
(i)power transfer regulation
(ii)derivation of equal area of criterion
(iii)change of load
(iv)change in transfer reluctance due to switches
(v)change in transfer reactance due to faults

--derivation of swing equation
--swing cap
--methods of improving both transients and steady state stability