Reclosers
What is exposure
Exposure is defined as end of the line fault current that will not be interrupted by the nearest upstream protective device within 3 seconds.
What does a sectionalizer do?
A sectionalizer is a device that opens to isolate a fault after it senses over current and a loss of voltage after set number of times, within a pre-determined amount of time, due to the operation of the next up-stream re-closing device.
How do you bypass a substation regulator?
Place in Manual, Step to Neutral, Power switch to off, close the bypass (DX), Open DB and DL.
Why are cap banks important in a distribution system?
keeps power factor close to 1 - which improves efficiency and provides economic savings. Also helps to maintain system voltage
Does DOC clear Line Regulators? Explain your answer
No. because the switch on a line regulator is a double throw switch, which is always energized. Instead we simply bypass a regulator when needed. It’s important to point out, that even if the regulator was isolated from the system, this would still not create an open point for a clearance
What is the purpose of Ground Trips, and which reclosers have them?
Ground Trips monitor phase imbalance on a 3-Phase circuit between phases A, B and C. If a phase imbalance exceeds the protection devices setting, the Ground Trip relay will open the protective device. Device Designations that start with T and V.
What is the benefit of a sectionalizer?
isolate fault, reduce number of customers impacted by an outage. For example, if the sectionalizer opens, the operator knows the fault is at the end of the line.
Do you need a Clearance to replace a Line Regulator?
No, work can be done under Clearance Exception Rule CH12-2 C (pg 142) in the APM.
what is the purpose of the kyle switch?
These Oil Switches bring the capacitor online and offline and are designed to break capacitive load.
Do you need a clearance to replace a sectionalizer?
Answer: No, work can be done under Clearance Exception Rule CH12-2 C (pg 142) in the APM.
Why is DOC concerned about the power controls for a recloser when picking up load from a downstream Normal Open.
Some recloser PT controls are only fed from one direction, which prevents the recloser from operating like a recloser when fed from the opposite direction. This condition is called “backfeeding” and simply means the old-style OCR will only operate 1 time before locking out, because the control power is de-energized when it operates.
How many clearance points does a sectionalizer have?
2
A regulator typically adjusts voltage by how much?
5/8% at ¾ of a volt increments (120V base 5/8%=.75 Volts)
How do you take an OH Capacitor Offline?
Place on manual, trip offline, and open the cutouts
Can you clear an OH Capacitor to use as a clearance point?
No, when you isolate an OH capacitor it does not create an open point in the system.
When establishing a clearance on a recloser, what is the preferred clearance point?
When you clear a sectionalizer, why do you have to remove load and line side jumpers?
to get a visual open (sectionalizers and reclosers do not have a visual open)
What are the differences between a substation regulator and a line regulator
The major difference between line and substation regulators is the fact that a line regulator has double throw bypass switches and substation regulators have 3 individual switches (DB, DX, and DL). Sub regulators also have to be in manual/neutral power switch to off to bypass. Substation regulators are also typically bigger in size, since they carry a larger load.
What do you do if there's a stuck kyle switch?
If a Kyle switch gets hung up, you’ll need to go back to the breaker to de-energize. De-energizing from the cabinet could burn it up. Upstream switches/elbows won’t have this high of a load break capability either, this is why you’d need to go all the way back to the breaker.
How do you clear a substation Regulator?
Place on Manual, Neutral, and power switched to off prior to closing substation regulator bypass switch DX, Open and Tag DB, Open and Tag DL
If a recloser has exposure, what has to be done to bypass it?
Some reclosers will have exposure when bypassed and as a result must be fused when bypassed to limit exposure.
If there is a fault between a sectionalizer and its upstream recloser what is the state of each device? Explain your answer
Sectionalizer would be closed b/c it didn't see the fault. Recloser would lock out since it saw the fault and it wasn't cleared during the reclosing process.
How can you tell the difference between a Substation Regulator that is under ECC control versus one that is under DOC control
Placement of the regulator. If its 44/45 (low side of 43s) it is typically DOC jurisdiction, 41 (high side of 43s) is typically ECC jurisdiction.
How do you take an UG capacitor offline?
Place on manual, trip offline, and de-energize from upstream device (elbow for DV and switches for livefront)
What steps have to be taken for the field to bypass V123456 for recloser maintenance?
place on local, disable reclosing, disable ground trips, close the bypass blades (creating loop), open the recloser (opening loop and dropping load), remove line and load side jumpers (eliminating backfeed)