isolator by anuj
TRANSCRIPT
ISOLATOR
Standards Referred
IEC 62271-102 (High Voltage Switch gear and control
gear)
IEC 61128 (Alternating current disconnectors – Bus-
transfer current switching by disconnectors)
IEC 60060-1 (High-voltage test techniques)
IS: 9921 (Alternating current disconnectors)
IEC 60694 (Common Specifications For High-Voltage
Switchgear and Controlgear Standards)
Purpose of Isolators
Used to isolate the circuit under no load
conditions.
Used for isolation of networks for small
switching currents (<0.5 A) and also for
commutation currents.
Cannot be used to make or break the
circuit.
It is used in addition to Circuit Breakers.
Types of Isolators
Horizontal centre Break isolator (Two column Rotary Disconnector) (72.5KV – 765 KV)
Horizontal Double break Isolator( Three column rotary Disconnector) (12 KV – 765 KV)
Vertical Break Isolator( Two column Vertical Break Disconnector) (<25KV)
Knee Type Isolator (33KV – 765KV)Pantograph Isolator( Single column
Disconnector)(145KV – 765KV)
Horizontal centre break Isolator
Horizontal Double break Isolator
Vertical Break Disconnector
Knee Type
Pantograph Insulator
Operating Mechanism
Motor Operating MechanismSpur Gear followed by Worm Gear is installed for smooth operation and self locking
Manual with Gear MechanismHand operation with Worm Gear is used for self locking capability
Manual OperationHand operation using lever is
practiced
Spur Gear Worm Gear
Earth Switch
Connected between line conductor and
earth.
Usually mounted on frame of isolator.
Interlocked mechanically and electrically
with isolators
Single Coloumn Earth Switch
TerminologyParticulars Data for 400
KV
Rated Current under site conditions at 50ºC ambient
2000/3150Amp.
Rated Short Circuit current of Isolator and E/S for 1 sec.
50KA(rms)
Rated dynamic short circuit withstand current of Isolator and E/S.
125 KA(peak)
Rated Mechanical terminal Load
Dielectric Withstand Capacity 520 KVrms
One min. power freq. withstand voltagei. Against Groundii. Against Isolating Distance
520KVrms610KVrms
1.2/50 µsec. Impulse withstand voltagei. Against Groundii. Against Isolating Distance
1425KV(peak)1450(+240)KV(peak)
Corona Extinction Voltage 320 KVrms
Operating Time Less than 12 Sec.