Where is the Communication Protocol to be followed by the PIC and field worker found?
The repeat-back procedures can be found in the SPR’s and also SOO 1T-13
What category of PSSP must a worker be authorized to in order to receive an SPG?
What is a Designated Isolation Point? Where would a DIP be recorded?
When equipotential grounding is not practicable at the worksite (This only applies to the station feeder cable work), worker control will be established at the Designated Isolation Point (DIP) by placing a Grounding/Blocking Protection Tag immediately upon receiving a SPG.
It is the worker’s responsibility to identify to the PIC if a DIP is required.
If DIP is identified then it must be agreed to during the issuing of the SPG and must be recorded on both the BC Hydro Control Centre and field worker’s SPG forms.
The DIP is to be the last point to have worker control removed before returning the SPG.
The PIC will confirm that Grounding/Blocking Protection Tags have been removed from the DIP as the first step of switching instructions to restore the equipment.
What fundamental questions must be answered by the field worker when returning an SPG to the PIC?
is equipment ready for service, whether or not worker protection grounding/blocking is removed, station riser’s installed and phasing req’d
What System Operating Order defines the life cycle of an SPG card?
What are the PIC’s responsibilities following the return of an SPG declared “Not Ready for Service”?
Check the “Not Ready for Service” box on the SPG card and file it in the returned pile.
What are the PIC’s responsibilities following the return of an SPG with “Worker Protection Grounds Applied”?
Check the “Worker Grounds Applied” box on the SPG card and check the “Not Ready for Service” box on the SPG card and file it in the returned pile.
What are the PIC’s responsibilities following the return of an SPG with phasing requirements?
The PIC will have to include phase checks in the switching order when switching the equipment back into service.
What is a Guarantee of Isolation and how is a GOI recorded?
A Guarantee of Isolation is an assurance from one authority to another that a piece of equipment is isolated and will remain so. It is tagged where required and also recorded in the logs of each desk.
What is a Transfer of Operating Authority and how would a TOA be recorded between a Load Desk and adjacent Grid Desk at FVO?
A TOA is tagged in the mimic and also logged in both desk logs.
What category of PSSP must a worker be authorized to in order to receive a Live Line Permit?
What category of PSSP must a worker be authorized to in order to receive an Assurance of No Reclose Permit?
What is a Guarantee of No Reclose?
A GNR is a guarantee between two adjacent authorities that reclosing is off and will remain so.
What tool is used by the Load Operator to log the issuing and returning of Live Line Permits, Assurance of No Reclose Permits, and Guarantee of No Recloses?
CROW and also the desk log for on the fly LLP
What should a Load Operator always reference prior to switching in a substation?
Load Operator should always reference the Stating Operating Order prior to switching in a substation.
Describe the “5 R’s” of switching.
Readings: All associated readings on ccts being switched from the max demand sheets
Ratings: Ratings of all equipment involved can they handle the anticipated load
Recloser: Is there a recloser on the ccts being switched. Should they be turned off prior to switching
Reactors: Are there reactors on the ccts being switched, what is there impedance and how will they share the loading during parallel switching
Regulators: Are there voltage regulators on the ccts being switched, are the ccts same source or different source? Field parallel or station parallel for NCO rules
What is a low-side or low-voltage tie?
A low-voltage tie is when two transmission lines are tied together on the secondary side (or low side) of the station transformers instead of the primary side (or high side)
What are the two general types of isolation points? Give examples of each type.
The two types are:
Conventional: disconnect switches, circuit switchers, fuses, rack-out cct breakers, etc.
Non-Conventional: Temporary line cuts like riser, a section of bus, a flying tap, a jumper between two dead-ends, a drop lead, etc.
What must be done to an isolation point in order for it to be used in support of a Safety Protection Guarantee?
The isolation point must be tagged in the field and on the PSSP MIMIC display
True or False – Voltage Transformer secondaries are Level 5 equipment and therefore, when located inside a Clearance zone, should be opened and tagged Self Protection to prevent backfeed prior to going to work.
Why are gas relays opened and tagged Caution when isolating a substation power transformer?
To make sure they don’t accidently operate while crews are working around or on transformers.
How is a transfer bus used to maintain service to a feeder position that is coming out of service?
The transfer bus allows two feeders to be paralleled together and then carry the feeder being taken out of service on the transfer bus by breaking the parallel
Describe how series reactors can affect load sharing when paralleling feeders.
The impedance of the reactors will determine how the current will flow once the parallel connection is made
Where is the criteria listed for D3 switching involving series reactors?
Define feeder cable.
Feeder cable is the underground portion of a feeder that delivers power from the substation to the first switchable device in the field.
Where is the isolation of a feeder cable typically mimicked?
Both AREVA and POCC
How do cablemen request for station risers to be removed in advance of planned feeder cable work?
They will add it to the comments section of the Outage Request Form in CROW
How is the removal of station risers mimicked?
It is mimicked in AREVA by toggling the appropriate station pothead symbol to “risers removed”
What is ferroresonance?
It is a phenomenon that can occur on electric circuits that contain a capacitance in series with a nonlinear saturable inductance. When ferroresonance occurs, it is typified by unpredictable nonlinear over voltages with high harmonic content and can lead to equipment damage and failure.
Where is the feeder cable switching procedure to be followed by Load Operators found?
What must be done prior to opening pothead sleeves on a feeder cable and why?
Prior to pulling the pothead sleeve, confirm current to be less than 2 amps. This procedure ensures that load will not be dropped or a parallel broken on the sleeve.
What is a standby circuit?
A standby circuit is a dedicated circuit that carries no load and that can parallel two feeders in the field via a NO switch
How can a standby and partial standby circuits be identified on AREVA and POCC?
A standby circuit is identified by a solid red box around the feeder text and a partial standby circuit is identified by a red dashed box around the feeder text
How can maximum demand readings be used to help make operational decisions?
They will help in the calculation to make sure that equipment ratings or relay settings will not be exceeded.
How can a feeder’s kVA report be used to help make operational decisions?
When sectionalizing and off-loading a feeder it will allow the operator to open and close switches with confidence that equipment ratings and relay settings will not be exceeded.
What operating prints are currently used in the Control Centre to operate and mimic the URD system?
Underground Distribution Diagrams, Underground Distribution Schematics, or Distribution Operating Diagrams
Describe a URD loop system?
This is an underground system that has multiple feeds to provide alternate sources for the URD primary. Normally the loop will have a dedicated NO switch roughly ½ way through the loop itself.
What is the normal procedure for switching on a URD loop system?
Switching must be “break” before “make” unless testing has been done to confirm phasing.
What factors must be considered when closing a loop on the URD system and why?
Make sure the phasing is correct and the amount of current flowing once closed will not blow fuses and the parallel will be able to be broken
What is the purpose of a CNE?
The purpose of a CNE is to energize new equipment in the substation.
What part of the power system requires a CNE for the commissioning of equipment?
Inside the substation fence or the station one-line
Following the completion of a CNE, what must be done if an updated EMS one-line display is not ready for upload to reflect the changes to the system?
Notify the day shift manager of the changes and they will have the one-line updated ASAP.
What is a Plant Alteration?
Plant Alteration is the addition or removal of distribution equipment outside the station fence and less than 60 kV
What is the purpose of the PA process and what operating order is the process defined in?
What is PAT?
Plant Alteration Tracking program tracks the PA’s from issue to completion
What is the role of the PA Coordinator?
PA Coordinator completes the PA in PAT and requests new drawings if required.
When working on a PA to install a new underground loop connection, at what point is a Safety Protection Guarantee required?
Before terminating the last cable at either end, worker must request SPG from the PIC
with isolation devices from both ends of the cable. No SPG is required to pull the cable in
an empty duct. Cable is installed without any SPG.
What are the Load Operator’s responsibilities following the completion of a PA?
The load operator will make sure that the Mimic is up to date with all the changes and then signoff the PA as complete and file for the PA Coordinator.
What is a PACTOR?
PACTOR is a Protection, Control and Telecom Operation Report that is used to bring new protection, control and telecommunications into service.
When commissioning protection, control, and telecommunications equipment; when is a PACTOR not required?
PACTOR is not required if the equipment installed is being done with a CNE. You don’t require a CNE and a PACTOR
Briefly describe the process for commissioning a brand new field recloser with supervisory control.
The field worker would call in the PA as complete. There would also be an energization plan including testing steps. Confirm the recloser is located in AREVA and follow the energization and testing plan step by step. Update drawings to show the new recloser and notify the day shift manager that the equipment is now in service and any temp AREVA screens can now be made permanent. Complete PA
What is differential protection?
Differential protection operates when the difference in the current entering and exiting the transformer goes beyond a preset threshold.
What is the advantage of using differential protection over simple over-current protection to protect transformers?
By using differential protection the transformer protection would only operate on internal faults and not normal load conditions or external faults.
What is the limitation of using over-current relays to employ differential protection?
The over-current relays must be set above any error current that can flow on an external fault. This reduces sensitivity.
How do percentage differential relays increase the sensitivity of differential protection?
They use operate and restraint coils. On an internal fault, the high magnitude differential current overcomes the restraint, and the relay operates.
How can magnetizing inrush current pose a problem to differential protection?
Magnetizing inrush current appears to a differential relay as an internal fault because it doesn’t flow out the other side of the transformer. Higher end relays are designed to block tripping if the second harmonic gets beyond a set threshold.
How are a gas relay’s alarm and trip outputs triggered?
An alarm is triggered if a fault causing gas to displace the oil in the relay chamber. A trip is initiated upon a larger fault that vaporizes the oil resulting in a build-up of gas pressure. This pressure will trigger a gas relay micro-switch to initiate trip
What two conditions in combination will trigger “bullet-hole” protection?
A low oil alarm and gas accumulation alarm are connected in series to initiate a trip.
How does a winding temperature device measure temperature? What is it used for?
Temperature measured by the thermometer depends on the top oil temperature and the current in the transformer winding. Used in protecting against overload and will initiate alarms, cooling, and tripping as required.
How are faults cleared on substation transformers without high-side circuit breakers?
A SOG will operate causing the remote line terminal protection to operate.
What is transformer auto isolation?
If a circuit breaker trips on protection the transformer disconnects are automatically opened to isolate the transformer. They cannot be closed until the lockout is reset manually.
It is a separate, time delayed output of the relay. The first step for relay operation is to send trip signals to the circuit breakers, then it will start timing. When the timing is finished the relay sends open commands to the required disconnects and locks them out through an 86 device.
What type of relay is generally used in bus protection?
Overcurrent relays. These over-current relays may be torque controlled using under-voltage or distance elements.
How must the phase and neutral relays of bus protection be set in terms of coordination?
Phase relays must be set above the max load current and must coordinate with feeder phase over-current relays. The neutral relay only needs to be set above the ma load unbalance, so the neutral relay can be set more sensitively.
What is the purpose of torque control and how does it function?
Torque control is used on buses that have very heavy load, and keeps the bus protection from operating on load current. It ensures if the fault is on a feeder the feeder protection operates first, and if the fault is on the bus, then bus protection will operate.
What is the risk in using the under-voltage method of torque control?
Loss of voltage to the under-voltage relay may cause bus protection misoperation
Why would a distance relay be used to provide torque control?
A distance relay is used where a feeder reactor is located on the source side of the feeder breaker. It is used to detect a bus fault and then provide torque control to the CO relay
What is the risk in using the distance method of torque control?
Loss of voltage to the distance relay will prevent bus protection operation for a bus phase fault.
Describe typical substation feeder relaying.
The feeder breaker will trip on a phase-to-ground fault, phase-to-phase fault or a three-phase fault.
How is a feeder fault cleared if the feeder circuit breaker fails to operate?
If the feeder circuit breaker failed to open on a fault, then the bus protection circuit breaker would open.
How does a fused cutout function?
The cutout is a fuse link that can be closed. Under a fault condition the fused link melts and the cutout hinges swing open.
What is an expulsion fuse?
An expulsion fuse is the type of fuse used in the cutouts.
How does the fault protection provided by vista switchgear differ from that of a switching kiosk?
A switching kiosk uses fused protection, where a vista switch uses load-interrupter switches in series with vacuum fault interrupters.
How are the majority of dead-front transformers protected?
They are protected expulsion fuses and backup current limiting fuses.
Can a bay-o-net fuse be used to break load in an LPT?
Technically it can, but BC Hydro’s practices say no.
How are shunt capacitor banks primarily protected? What benefits does this provide?
They are primarily protected by individual capacitor current-limiting and expulsion fuses. It can allow continued service by only removing the one damaged unit, prevents damage to adjacent units or personnel and can provide easy visual indication of a failed unit.
What means of protection can be provided to isolate a shunt capacitor bank from the system in the event of a major fault?
In the event of a major fault the breaker will trip separating the capacitor bank from the system.
Why is neutral-shift over-voltage protection applied to shunt capacitor banks?
To protect against a shift in the neutral potential that can be caused by failed cans
What type of feeder outage will a Load Operator be most concerned with?
Sustained outages on Level 4 portions of the feeder.
What are the most typical causes of feeder faults?
Trees or branches, MVA’s, animals, fire, insulator failure, broken cross arms, ice load, lightning, pothead failure, UD elbow failure, cable failure, etc.
What should a Load Operator suspect as the possible cause of a sustained feeder fault when there has been no report or evidence as to the cause of the fault?
Can be caused by a feeder cable fault
What are some typical causes of substation equipment outages?
Planned forced outages for maintenance or replacement, or non-planned FOS failure of equipment like faults in transformers, voltage regulators, reactors, etc. Capacitor banks may trip due to can failures. Circuit breakers and disconnects can fail during operation. Any cable may fail as well.
What has BC Hydro done within their substations to help prevent animals and birds from causing equipment outages?
BC Hydro has installed animal and bird guarding in substations to protect the busses and equipment from being contacted.
Where is BC Hydro’s feeder reclosing policy documented?
How long does a Load Operator have to attempt a manual reclose on a feeder circuit breaker following a trip?
How can a Load Operator determine if reclosing is permitted on a given feeder circuit?
The appendix of 1D-51 lists whether a feeder reclosing is permitted. In AREVA the breaker will have an X through it to indicate no reclosing.
Where is BC Hydro’s distribution substation bus reclosing policy documented?
How can a Load Operator determine if bus reclosing is permitted at a given substation?
The appendix of 1T-29B lists whether bus reclosing is permitted. In AREVA there is a statement right below the station label that says “FEEDER BUS RECLOSING IN EFFECT” if a station bus can be reclosed. If someone is in the station this will change to “DO NOT RECLOSE”. In general indoor substations will not have bus reclosing as the chance of a transient fault are pretty much zero
What is cold-load pickup?
Cold-load pickup is the loading imposed on the distribution system following a
prolonged service interruption, during which diversity among thermostaticallycontrolled
loads such as electric heaters, ranges, and air conditioners has been
When is a feeder outage considered to be momentary and when is a feeder outage considered to be sustained? What are the Load Operator’s responsibilities in terms of reporting?
Sustained outages are longer than 1 minute. Load Operators are responsible for notifying the System Control Manager on shift when a system event occurs that requires reporting such as a major loss of customers, electrical contact, or equipment damage.
How are Power Line Technicians dispatched?
Through the Hydro Restoration Center
How are Station Electricians and CPC Techs dispatched?
Dispatched through the control center. Follow 1T-82 for station callouts
General and role-specific logging procedures can be found in what operating order?
What must a Load Operator first do upon assuming PIC duties?
Must sign the log
When is a Switching Order required?
Switching order is required when more than 2 switching steps are being completed
The Switching Order procedure is defined in what operating order?
Where are the definitions, rules, and procedures pertaining to Safety Protection Guarantees found?
In the Safety Practice Regulations (SPR) section 600
In addition to recording the issue of a Safety Protection Guarantee with an SPG card, what additional logging must take place?
The SPG must be entered into the paper based log for pending, issued, returned and completed.
What is the purpose of POCC?
To mimic level 4 main trunk equipment outside the substation fence
What operating order describes the guidelines for using and updating POCC?
What operating order describes specifically how POCC is to be used as a mimic display?
How are reclosers and SCADA switches displayed in POCC and why?
Reclosers and SCADA switches are displayed in blue and indicates that the device status must be verified in AREVA
What does the “L” symbol displayed in the POCC Schematic Window represent?
It represents a loop or possibility of back-feed
What is a composite schematic?
Composite schematics display multiple feeders on the same schematic.
Why is the POCC Geographic Window not used for operating in real time?
It is not maintained in real time and doesn’t always show the current status of the system
How can updates be made to POCC schematics in real time? What is the preferred method of updating a POCC schematic?
The preferable way to update a POCC Schematic is electronically with the
POCC Schematic “Editing” and “Redline” tools.
Generally speaking, what is the purpose of the CROW application?
To track outages, permit scheduling, operations logging, notifications, reporting and alarms
What line of operating orders are the CROW guidelines described in?
What are the four different browsers within CROW?
Outage requests, events, permit requests and station/field reclosing
What must be done in CROW when an approved Outage Request is taken?
You should implement the CROW
When should an implemented Outage Request in CROW be completed?
When you receive the call from the worker stating the job is completed
What events are logged in the CROW Events Browser?
Used to track forced outages, carried by, unusual conditions, alarms and EMS/SCADA
What events are logged in CROW as Forced Outages?
Events involving station equipment within their area of operating responsibility, outage events involving sustained distribution system feeder outages and associated equipment. Momentary feeder outages will not be entered in CROW as per DOO 1D-10, events involving Bulk customers that connect to the distribution system and events involving IPP generating units larger than 20 MW connected to
the distribution system.
What is the general purpose for logging Forced Outages in CROW?
• To capture availability/unavailability of equipment and circuits,
• To record significant operating reconfigurations that impact reliability,
• To record customer impacts, and
• To record SDR data.
What are Parent and Related Outages?
Parent outages are the highest cause of the outage. For example the parent outage a bus is out do to birds and bus breakers are open, so all associated feeders are out as a related outage
Why are Carried Bys logged in CROW?
To log abnormal feeder configurations and to un-approve LLP and ANRP’s on the feeder involved to be researched again
What is an Unusual Condition?
A change from the normal state or condition of equipment, that impacts the operation of the system or system equipment, where it is expected to be returned to its normal state in the near future.
What operating order describes alarm handling and the criteria for entering alarms in CROW?
How are AREVA analog alarms that are nuisance or may indicate failure of equipment entered into CROW?
They are entered as EMS/SCADA events not alarms
What is the purpose of the Permit Requests Browser (P3)?
It is used to track all of the LLP, ANRP and GNR permits
What is the purpose of the Reclosing Browser?
The primary function of the “Reclosing Browser” is to provide a tool that can
be used to inform the field of manual reclosing requirements.
What areas of the province use the Reclosing Browser?
Load desks 4-10
Every night, after the day’s permit requests have been processed, what manual task must be performed by the Load Operator and why?
Every night, after the day’s permit requests have been processed, the responsible Load Operator will sort through the “Reclosing Browser” and update two columns:
• Reclosing Off Required
• Reclosing On Required
What operating drawings are produced by DAD for use in the control room?
Distribution Operating Diagram (DOD), Underground Distribution Diagram (UDD) and Primary Maps
What is the purpose of the “Yellow Sheet Check” performed by the Load Operator?
• To check that a PA has been correctly updated on DAD and matches
the red mark up on the print (UDD or Primary Map)
• To compare a new print against the current print to make sure the new