Medium voltage electronic sectionalizers AutoLink
Save time, effort and money!
The ROCKWILL AutoLink sectionalizer is an isolating device that automatically isolates the faulted section of the overhead network when a permanent fault occurs. If a temporary fault occurs, the AutoLink allows the upstream recloser or breaker to clear the fault without interrupting the circuit. Both AutoLink electronic sectionalizer and the wireless version of Autolink, AutoLink, are designed to improve reliability and service continuity.
Increased reliability and continuity of service, discriminating between temporary and permanent faults
Inventory reduction: one size fits all current ratings
Simple and quick installation without special tools
Reduces maintenance time: field configurable and resettable
Reduced operation costs
Only three voltage levels: 15, 27 and 38 kV
Nominal current and number of counts settable by user
No external power source required
AutoLink family: single-phase, loadbreak, mechanical three-phase and wireless three-phase
Independent of the time-current curve
The sectionalizer is applied in three phase power system with AC 50Hz and rated voltage 10-40.5kV. It is installed on distribution overhead line to isolate fault when corporated with recloser or circuit breaker. When fault occurs on the line, the faults current reaches or exceed preset threshold value, the sectionalizer can remember the tripping times of upstream recloser. When it reaches preset times, it drops down to trip automatically.
Sectionalizer can drop down to trip automatically on the condition as given below:
First, the faults current exceeds presetting pickup current. Second, the counting time reaches presetting value (1, 2, 3 or 4). Third, the circuit loses voltage and the current is lower than 300mA. The Sectionalizer will trip automatically if the aforesaid conditions occur simultaneously. If any of aforesaid conditions doesn’t occur, the Sectionalizer will not trip automatically.
This sectionalizer uses micro-computer and operating trip mechanism and does not require external auxiliary supply.
The current transformer built in the cutout sectionalizer can detect the current of the main circuit and send the output to the electronic control for digital handling. When a fault occurs, the upstream recloser (or circuit breaker) open, the circuit loses voltage and the current is lower than 300mA, the electronic controller can remember this opening time as a “count”, when it reach the presetting number (1 to 4), the sectionalizer will automatic trips within 180ms of fault interruption to isolate fault. Then the upstream recloser ( or circuit breaker) close to restore power supply to the healthy section of the system to limit outage scope and protect the mainfeeder in service. If the fault is temporary and is cleared before the sectionalizer counter reaches the presetting number, the sectionalizer remains closed and resets to its original state after its reset time expires.
Normally, the sectionalizer is applied in conjunction with an upstream recloser or circuit breaker.Refer to the diagram.
The recloser applied in the substation is set( “1 fast and 2 slower’)3 shots to lockout and 6 unitscutout sectionalizers (F1, F2, F3, F4, F5, F6) are applied in the four branch line to separate 7 section( L1, L2, L3, L4, L5, L6, L7). The counts of F1 is set to 3 time, F2, F3, F5, are set to 2 times and F4,F6 are set to 1 times.
1. If there is a fault E1 in section L5, a fault current flow the recloser and sectionalizer F1, F3, F4,The recloser trip and all the line lost voltage, The sectionalizer F4 trip after it reach to the presetting “count” number 1 and isolate the fault section L5, the rescloser reclose and restore the healthy section L1, L2, L3, L4, L6, L7 to service.
2. If a fault E2 in section L6, a fault current flow the recloser and sectionalizer F1, F5,the reclosertrips; if the fault is temporary, the recloser reclosesto restore the line in service, then the sectionalizer F1, F5 remains closed and resets to its original state after a presetting time since itdoes not reach the presetting count number,. if the fault is permanent, the recloser failsto reclose successfully and trip again, all the line lost voltage and the sectionalizer F5 trip to isolate faultsection L6 after it reaches the presetting count number.
3. The sectionalizer F1 remain closes state since it does not reach the presetting count number. The recloser reclosesagain and restore the healthy section L1, L2, L3, L4, L5, to service.
4.If a fault E3 in section L2, a fault current flow the recloser and sectionalizer F1, the recloser trip.If the fault is temporary the recloser reclose to restore the line in service, then the sectionalizer F1remains closed and resets to its original state after a presetting time since it does not reach the presetting count number. If the fault is permanent,the recloser fail to reclose successfully and tripagain all the line lost voltage and the sectionalizer F1 trip to isolate fault section L2 after it reach the presetting count number 3, The recloser reclose again and restore the healthy section L1 to service.
The count number of sectionalizer is set 1 time normally as it applied in the end of substation
because almost fault occurring at the end of substation is permanent and is set 2 or 3 times applied
on the overhead line because almost fault applied on the overhead line is temporary. In this co-ordination, the sectionalizer can easily and optimized co-ordinate.
|4||Pickup current rating||A||8~400A||8~400A||8~400A|
|5||Short time withstand current(RMS)||KA||10||10||10|
|6||Short circuit withstandtime||s||1||1||1|
|7||Short time withstand current (PEAK)||KA||16||20||20|
|8||Counting time||time||1, 2, 3, 4||1, 2, 3, 4||1, 2, 3, 4|
|9||Max memory time||S||20||20||20|
|10||Max reset time||S||20||20||20|
|11||Permissible deviation of pick up current for memory rest time||%||±10||±10||±10|
|13||Main circuit resistance||μ Ω||≤400||≤400||≤400|
|15||Horizontal pulling force of terminal||N||250||250||250|
|16||Manual open moment||N·m||——||——||——|
|17||Manual open force||N||≤120||≤120||≤120|
|18||BIL(phase to ground)||KV||110||185||185|
|20||PFWV(phase to ground)||dry||
|22||PFWV of control circuit||KV||2||2||2|
|23||Dirty proof grade||Class||Ⅳ||Ⅲ||Ⅲ|
|24||Ice proof thickness||mm||≤7||≤1||≤1|
|25||Pickup current (four classes) and Counting time can be set||——||YES||YES|
|26||Mechanical interlocking for 3 phase devices and automatic reset||——||YES||YES|