In-Country Training
On
Operation, Maintenance, Protection & Control of 33/11 kV Substation
Project Name: Design, Supply, Installation, Testing & Commissioning of 33/11 kV sub-stations with source end feeder bays.
Contract No: BREB/UREDS/W-01A-001/02/2016-2017
BREB/UREDS/W-01A-002/03/2016-2017
BREB/UREDS/W-01A-004/04/2016-2017
2. TRANING ON
11 KV BREAKER WITH PANEL
33 KV INDOOR BREAKER WITH PANEL
33 KV OUTDOOR BREAKER
RELAY SETTING TOOLS
SHORT VISIT ON RMU
3. HOW BREAKER WORKS?
A mechanical device capable of making, carrying and breaking currents
under normal conditions as well as under specified abnormal
conditions such as those of short circuit.
Fault Occurs
Relay
• Senses &
Relay Contact
Closes
Circuit Breaker
• Trip Coil Energises
• Operating Mechanism Starts
• Contacts Separate
• Arcing between Contacts
• Arc Extinguishes
• Circuit Breaker Fully Opens Fault Cleared
7. Dielectric Recovery Property Of Various Media
101
0
20
40
100 1000
SF6
10000
60
80
Vacuum
N2
H2
Time [micro-seconds]
Dielectricrecoveryvoltage[kV]
8. Interruption Principle
PUFFER TYPE:
Involves compression of gas between a static piston and a moveable
cylinder during interruption action.
Compressed gas is blown through nozzle in which arc is burning.
SELF EXTINGUISHING TYPE:
Heat/ionization effect of arc causes gas pressure to increase in sealed arc
chambers.
Over pressure causes turbulence in gas and forces it out as soon as nozzle
starts to open.
This phenomena has strong effect on arc, making it thinner,
cooling, interrupting and providing rapid dielectric recovery
11. Interruption Principles
SPIRAL CONTACTS
* To prevent overheating and contact
erosion, the arc is kept rotating
*The special geometry of the spiral
contacts generates a radial magnetic
field in all the areas of the arc column
12. Motor Switching with VCB
ARC EXTINCTION AT CURRENT ZERO IS NOT POSSIBLE.
(MIN +/-5A FOR ALL MANUFACTURERS)
CURRENT CHOPPING IS IN EVITABLE FOR INDUCTIVE
LOADS
I.E.SPECIFICALLY MOTORS WITH LOW LOAD
CURRENTS(e.g.NO LOAD)
MOTOR HARMONICS GIVES RISE TO VIRTUAL CURRENT
CHOPPING
Better solution with SF6 CB
13. Capacitor Switching with VCB
CAPACITOR SWITCHING AT LOWER CURRENT IS DIFFICULT WITH VCB
BECAUSE…..
GAP BETWEEN MOVING CONTACT AND FIXED CONTACT IS VERY LESS
(8-10MM APPROX).CONTACT SPEED IS ALSO LOW (1M/S.APPROX)
AT LOWER CAPACITTIVE CURRENTS, ARC EXTENGUISHES EARLY
WITH HIGH RESTRIKING VOLTAGE (VOLTAGE OF CAP IN ADDITION)
ACROSS CONTACTS WITH A GAP OF 2MM APPROX.
Result
Multiple restrikes hinders smooth switching of capacitors
and capacitor as well as VCB contacts may damage
Better solution with SF6 CB
14. SF6 & VACUUM SWITCHING TECHNOLOGIES
SF6 CIRCUIT BREAKER VACUUM CIRCUIT BREAKER
SF6 GAS PRESSURE MONITORING VACUUM CAN NOT BE MONITORED.
POSSIBLE.
FALL IN PRESSURE CAN BE ANNUNCIATED. LOSS OF VACUUM WILL BE KNOWN WITH
CB FAILURE.
CAN INTERRUPT RATED CURRENT EVEN HAS TO BE TAKEN OUT FOR
AFTER GAS PRESSURE FALLS DOWN TO REPLACEMENT OF POLES.
ATMOSPHEREIC PRESSURE.
GOOD ELECTRICAL ENDURANCE. GOOD ELECTRICAL ENDURANCE.
INTERRUPTING CHAMBERS CAN BE INTERRUPTERS TO BE REPLACED (COST OF
MAINTAINED. REPLACEMENT 40% OF CB ).
SF6 BREAKER IS RUGGED. SENSETIVE TO ROUGH HANDLING.
WELL SUITED TO MOTOR DUTY OPERATIONS RELATIVEY INFERIOR FOR MOTOR
OVER VOLTAGE UNDER 2.5P.U. SWITCHING. SURGE PROTECTION ESSENTIA
17. 11 KV BREAKER (HHV-12)
Contacts protected against
oxidation and contamination
Vacuum interrupter embedded
in the resin poles
Vacuum interrupter protected
against shocks, dust and
humidity
Ensured operation under
different climatic conditions
Limited switching energy
High number of operations
Operating mechanism with high
reliability
20. Outdoor Vacuum Circuit Breaker OFVP 36
10000 operations at no load.
10000 operations at rated current.
Wide range of power supply
voltages of the electrical
accessories.
Mechanical anti-pumping device to
prevent re-closing due to both
electrical and mechanical controls.
Uses Hermetically sealed
interrupters.
Cabinet mounted on Hot-Dip
Galvanised steel structure.
Option to extend structure for
instrument transformers.