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The potential difference between two points of a conducting wire
A volt is the amount of potential necessary to cause 1 coulomb to produce 1 joule of work
The Rate of flow of electrons or through conductor
One ampere of current flows through a wire when 1 coulomb flows past a point in one second
An ohm is the unit of resistance to current flow
Define Ohm’s Law
All electric quantities are proportional to each other and can therefore be expressed as mathematical formulas.
From an electrical system perspective, what is a fault?
when a path to ground other than the intended path is established
explain a series circuit
one path for current flow
the current is the same at any point in the circuit
explain a parallel circuit
circuits that have more than one path for current flow
State Kirchhoff’s voltage law
The algebraic sum of the voltage sources and voltage drops in a closed circuit must equal zero
State Kirchhoff’s current law
The algebraic sum of the currents entering and leaving a point must equal zero
State the three rules for series circuits
- The current is the same at any point in the circuit.
- The total resistance is the sum of the individual resistors.
- The applied voltage is equal to the sum of the voltage drops across all the resistors.
State the three rules for parallel circuits
- The total current flow in the circuit is equal to the sum of the currents through all the branches
- The voltage drop across any branch of a parallel circuit is the same as the applied voltage
- The total resistance of a parallel circuit is the reciprocal of the sum of the reciprocals of the individual branches
Define inductive reactance
- The current-limiting property of an inductor in an AC circuit caused
- When magnetic lines of flux cut through a coil, a voltage is induced in the coil.
- An induced voltage is always opposite in polarity to the applied voltage referred to as counter-electromotive force (CEMF).
- The amount of induced voltage is proportional to the rate of change of current
What determines the strength of the magnetic field when current flows through a conductor
- The direction of the current flow determines the polarity of the magnetic field
- The amount of current determines the strength of the magnetic field.
In what form is energy of an inductor stored
A Magnetic Field
Define capacitive reactance
- The current-limiting property of a capacitor in an AC circuit
- As a capacitor is charged, an impressed voltage is developed across its plates as an electrostatic charge is built up. The impressed voltage is the voltage provided by the electrostatic charge. This impressed voltage opposes the applied voltage and limits the flow of current in the circuit
List three factors that determine the capacitance of a capacitor
- The surface area of the plates
- The distance between the plates
- The type of dielectric used
In what form is energy of a capacitor stored
A capacitor stores energy in an electrostatic field
What is the “Real Power”? What is the “reactive power”?
What is the “apparent power
- Real Power
- Measured in watts (W), is produced only when electrical energy is converted into some other form.
- Reactive Power
- Quantified as VARs when there is no net energy transfer of energy to a load. Calculated by multiplying reactive voltage by reactive current. Can be produced by inductive or capacitive loads.
- Apparent Power
- Quantified as VA. The complex vector sum of Real and Reactive Power and is what is measured in a circuit
Define power factor
Power factor (PF) is a ratio of the true power to the apparent power
- Angle Theta
- Is the cosine of the power factor
What is a transformer
- a magnetically operated device that can change values of
- voltage, current, and impedance without a change of frequency
- Transformers can be divided into three classifications:
- 1. Isolation transformer
- 2. Autotransformer
- 3. Current transformer
What is the PSSP
1T-12 Operating Orders
The constraints required to be applied to the power system to provide worker protection from power system hazards
What is the relationship between the PSSP and the SPR
SPR: A book of rules and instructions which govern work done on the power system.
PSSP: The System Operating Order which defines how the SPR are applied consistently throughout the power system
What must happen after a SPG is in effect (workers responsibilities)?
tested to verify isolation before grounding and blocking begins
verify that required grounding and blocking devices are in place before work begins.
With respect to Power System Definition, equipment included on BC Hydro’s power system as it relates to PSSP will be defined where?
System operating orders, distribution operating orders, station and circuit one-line diagrams
Each piece of major equipment on the power system will be uniquely identified by...
A number or alphanumeric designation
Explain what is meant by Central Control
- To ensure uniform control throughout the power system. A hierarchical central control arrangement is established by BC Hydro RTO
- Included in the hierarchy is the centralized control of the BC Hydro power system and defined stations
What is a PSSP Mimic Display?
A symbolic representation of the power system, used to indicate the operating positions of equipment and of field tagging
What is the definition of Operating Authority?
The right to control an assigned portion of the power system to establish the conditions required for and to issue Safety Protection Guarantees, Live Line Permits and Assurance of No Reclose Permits; to issue such Guarantees and Permits; and to establish work protection
Explain the responsibilities of both the PIC and the worker regarding Isolation for Safety Protection.
PIC: Responsible and accountable for determining the isolation required and the sequence of switching, locking and tagging necessary to isolate major equipment
Worker receiving a SPG: Responsible to check isolation using a combination of field checks and reference to operating diagrams and drawings. Testing will be required to ensure the equipment is deenergized before grounding and blocking
What are Distribution Operating Diagrams? What kinds of prints do they typically contain?
A family of drawings and schematic diagrams that represent the distribution system. Typically they are called Circuit Location Diagrams, Primary Maps, Distribution Operating Diagrams
What is the Official Log
Log which is used by the PIC to record system operation, Safety Protection Guarantees, Live Line Permits and Assurance of No Reclose Permits that are issued on the portion of the power system for which the PIC has operating authority.
What are Operating One-Line Diagrams
Electrical schematic diagrams that represent all station Level I through Level IV high voltage equipment
What is a Plant Alteration
Document that indicates changes required to a distribution system
What are the Power System Components?
All high voltage non integrated generating stations, high voltage circuits, switching stations, transformers, reactive equipment, distribution circuits and equipment used in the production (non integrated area), transmission and distribution of electrical energy
What does a Central Control Facility consist of?
a control room, communications equipment, mimic displays, logs, tags, operating orders, instructions, documentation and records a control room, communications equipment, mimic displays, logs, tags, operating orders, instructions, documentation and records.
What is Operating Responsibility
The responsibility for the operation and reliability of an assigned portion of the power system, as delegated by the hierarchical control arrangement
Operating Responsibility is documented in which SOO?
S.O.O.1J-11 and 1T-11A
What are PSSP mimic displays used for?
Used in operating the power system to indicate device status and for safety tagging of isolation points established for the purpose of issuing Safety Protection Guarantees, Live Line Permits and Assurance of No Reclose Permits.
A PSSP mimic display may consist of a combination of what
A combination of dynamic or static display boards, electronic displays (with a paper copy for backup), operating one line diagrams, or Distribution operating diagrams
With regards to switching, when is the mimic display tagged
After the switching is completed and before the SPG is issued
Is tagging part of the Switching process or the SPG process?
Is part of the switching process not the SPG process
What are the requirements for multiple SPGs with common isolation points?
Each guarantee will have its own set of tags on the mimic display
When are Distribution Operating Diagrams used as Mimic Displays?
Used to tag Distribution devices not shown on a Distribution mimic display
What is a Combination Display? What are the rules around tagging of Combination Displays?
- A combination of electronic displays, operating one line diagrams, or distribution operating diagrams
- When the mimic display consists of a combination of displays a caution tag marked “PSSP” with a note referencing one display to the other must be attached to each display
What Level of equipment is shown on PSSP Mimic Displays (not including Distribution Operating Diagrams used as Mimic Displays)?
All portions of distribution circuits where high voltage loops or multiple feeds exist
What is a Transfer of Operating Authority?
May be used by two PICs to move the operating boundary such that the required lines or electrical and mechanical apparatus are all within one area of control following the transfer
What is a Guarantee of No Reclose
A documented agreement from a neighbouring area, that is in control of a different authority, that there will be no reclosing at a specific location. Similar to a Assurance of No Reclose but given if part of the power system to be worked on is connected to plant controlled by a different authority
What is a Guarantee of Isolation?
A guarantee from a neighbouring authority that required isolation points under the neighbouring control have been locked and tagged before issuing a clearance to local crews.
What are the responsibilities of the PIC?
- Direct the operation and tagging of devices classified as level I through IV.
- Direct the isolation of any necessary level V devices, i.e. those level V devices listed on Safety Protection Guarantees.
- Issue all Clearances, Test and Work Permits, Guarantees of Isolation, Guarantees of NoReclose, Live Line Permits and Assurance of No Reclose Permits as may be required for the safe undertaking of work on the assigned portion of the power system.
- Maintain the official log.
- Keep a record of all Safety Protection Guarantees, Guarantees of Isolation, Guarantees of No Reclose, Live Line Permits and Assurance of No Reclose Permits issued.
- Hold a file of all cancelled permits.
- Maintain the mimic displays that represent the conditions on the portion of the power system for which the PIC has operating authority.
What is Customer Isolation?
To be followed when electrical isolation is required from the power system. This procedure will ensure that workers authorized by BC Hydro have isolated the electrical supply to the customer, and will not reconnect the supply until requested to do so by the customer
Where are the detailed responsibilities and procedures for issuing, receiving and returning Safety Protection Guarantees described?
In SPR 600
Immediately following the receipt of a SPG, a worker will
- Confirm the isolation (which may include level V devices).
- After receiving the SPG, but before going to work on the isolated equipment, the SPG holder will ensure that appropriate testing is performed to confirm de-energized conditions immediately prior to applying grounds.
Can the Self Protection remain on the equipment after the SPG has been returned?
Before the Safety Protection Guarantee is returned and prior to the removal of working grounds, the Self Protection that was applied must be removed and the auxiliary devices returned to their normal in-service positions provided no other Self Protection tags are in place
What is Self Protection?
Safety Protection Guarantee that a worker authorized to PSSP category 5 or 6 can apply on conductors or equipment for with a Clearance or Test and Work Permit is not required
Each PIC will have specific information and documentation applicable to the PIC’s area of operation. The information will be kept current and readily available. Examples of the required documentation are:
- Operating One Line Diagrams
- Distribution Operating Diagrams
- Unit Isolation Schematics (for non-integrated generating stations)
- Log Books
- System and Distribution Operating Orders
- Safety Protection Guarantees
- Switching Order Forms
What is a Switching Order Form
When a switching step sequence consists of three or more steps, the PIC shall use a Switching Order form and shall record the Switching Order number in the Log
All personnel involved in a work project involving two or more persons must participate in detailed __________ ___________ on all of the following occasions
- Tailboard discussions
- Before the work commences
- During the course of the work as required to accommodate changes in the work plan
- At the conclusion of the work
Fully explain the Switching Order Procedure?
- Specify the switching assignment and identify the operations and sequence of the operations.
- Confirm that the person that is to do the switching is authorized.
- Review the switching order carefully.
- Before performing an operation specified in the switching order, verify the location and operation of the correct equipment by checking the designations on the switching order and on the equipment.
- The mimic display will be updated by the PIC when the switching order is completed. The exception to this is specified in S.O.O. 1T-12F 3.0
What must be done if an unsupported field tag is discovered
The matter will be referred to the PIC, and then by the PIC to the PIC’s manager. The manager or PIC will undertake a thorough investigation and then the PIC can authorize removal of the tag if appropriate
Explain the Repeat Back Procedure
- The PIC shall issue directives in a clear, concise, and definitive manner;
- Shall ensure the recipient of the directive repeats the information back correctly;
- And shall acknowledge the response as correct or repeat the original statement to resolve any misunderstandings
What is System Component
Specific information for personnel required to have access, switch, or to work on the power system, must be trained in PSSP and relevant sections of the SPR as specified in operating order 1T-12
What is Functional Component
The functional component training will contain the appropriate safety and operating procedures for a specific function of the power system