Glossary terms beginning with R

Terms used within Transpower
Click one of the letters above to go to the page of all terms beginning with that letter.
R&I diagram

The R&I diagram is a single line representation of all or part of a Transpower station showing relevant details of the primary equipment, overlaid with details of the protection functions and the instrumentation.

rack

A standard-sized open frame on the front of a cabinet to support rack-mounting protection, communications or other low voltage equipment and equipment mounted on standard-sized plates.

racking/out (up/down)

Move a withdrawable type circuit-breaker into/out of its operating position.

radiation

The emission and propagation of waves transmitting energy through space or through some medium.

radio contact point

A location adjacent to a transmission line where radio communication to the access permit issuing station or relaying station is achieved in all weather conditions.

ramp

Move a generator or HVDC link to a designated load level at a specified rate.

ramp rate

The rate of increase or decrease at which the power is increased or decreased on a generator, HVDC link, or load. Expressed as MW/minute.

ramp up (HVDC)

The automatic change in mercury arc or thyristor pole power transfer during start-up, shutdown, or faults to attempt to maintain the required overall HVDC power transfer.

rated average life

Is the total operated hours when 50 % of a large group of lamps still survive. High pressure sodium lamps have long lives in excess of 20,000 hours. Compact fluorescent lamps have lives in excess of 10,000 hours.

rated voltage (arrester with spark gaps)

The maximum permissible rms value of power frequency voltage, applied between the line and earth terminals of the arrester with series gaps, at which the series gaps will reseal following sparkover.

rationalisation

Disconnector/earth switch rationalisation is to remove non-essential equipment from existing Transpower substations in order to reduce maintenance costs and system complexity while still maintaining the flexibility required for system operation.

RCA

For a measuring relay, the angle between the phasors representing two of the relay’s input energising quantities which is used for the declaration of the performance of the relay. [IEC 50 (446)].

RCB

An agreement made by the contact operator with an RCB holder whereby:a specified HVAC circuit will not be re-energised either automatically or by operator action; or a specified HVDC circuit will not be re-energised or have its voltage mode changed by operator action. A reclose block also serves as a formal notification to the operator that live line work is in progress. A reclose block is thus required irrespective of whether auto-reclose is installed on the circuit being worked on or not.

RCD

A device that senses a current imbalance as a result of earth leakage from that circuit and will disconnect that circuit when the imbalance exceeds a predetermined level.

re-commissioning tests

Tests similar to commissioning tests which are made after equipment has been modified or disturbed.

reactive gases

Are chemically active, corrosive and toxic.

reactive power

Energy that flows in the power system between alternators, capacitors, SVCs, etc. and inductive and capacitive equipment such as transmission lines and low power factor loads. It is the product of the voltage and out-of-phase components of the alternating current and is measured in vars.

reactive power control

A control system which monitors and controls reactive power flows to ensure system voltages remain within minimum and maximum limits. See also "not available to the reactive power control".

reactor

An electromagnetic device providing inductive reactance for current limiting and compensation for excessive capacitive currents.

reactor type on-load tap changer

An OLTC fitted with an impedance which may be additional taps on the main winding or a separate reactor to prevent short circuiting of the tapping section of the winding during tap changes.

ready for livening

The state of equipment which is not yet commissioned but declared as ready to be connected to the power system.

Ready for Livening Notice

The Transpower notice which confirms that the equipment to be livened is ready to be connected to the power system.

ready for service

A declaration made by an operator to the service centre. It indicates that an item of equipment which is released can be returned to the operational control of the service centre, that is the release can be terminated.

real time

From 13:00hrs on the day, up to and including 23:59 hours of the following day.

recall time

The estimated time required during the work for the contractor to: return the equipment in a condition suitable for service, and be clear of the equipment.

recently livened equipment warning notice

A notice to warn employees that the equipment listed is capable of being livened by an operating procedure, and which states that no further work can be done without an authorisation.

recipient (of authorisations)

An employee who requests, receives, holds, may request transfer of, and returns an authorisation. [SR - EI April 1995].

recipient-applied safety measures (SR-EI)

See safety measures.

reclaiming

A reconditioning process with the addition of anti-oxidants that remove most of the oil's oxidation products by an absorbent bed, such a Fullers earth.

reclamation

A reconditioning process that removes most of the oil’s oxidation products by an absorbent bed, such as Fullers earth, and that adds an anti-oxidant.

reclose block

An agreement made by the contact operator with an RCB holder whereby:a specified HVAC circuit will not be re-energised either automatically or by operator action; or a specified HVDC circuit will not be re-energised or have its voltage mode changed by operator action. A reclose block also serves as a formal notification to the operator that live line work is in progress. A reclose block is thus required irrespective of whether auto-reclose is installed on the circuit being worked on or not.

reclose block approval

Approval by the service centre to the contact operator for a reclose block to be issued.

recloser

The recloser is a self-controlled circuit-breaker with integral protection. It automatically recloses to restore service if a fault is temporary. It is capable of being programmed for repetitive reclosing operations.

reconditioning

A process to remove fine solids, free and soluble water, volatile acids and sludge from insulating oil by filtration and hot oil vacuum dehydration. Work, other than inspection and repairs, which involves significant dismantling to replace deteriorated or worn components or to carry out corrosion repairs. Also where the cost of the repair work meets the criteria of TP.GS 03.01 Appendix G. The work is normally carried out in a workshop environment.

record

Documentation/information providing temporary or enduring business value, including data on computer systems, created or recieved and maintained by Transpower in the transaction of business and kept as evidence of such activity. Transpower hardcopy records are stored and managed off-site by an out-sourced records management service provider.

rectifier

A self contained unit for converting a.c. mains to d.c. for charging a battery and supplying the load. This name is usually associated with modern switch-mode units.

recycled SF6 gas

Is SF6 gas that has been recovered and returned to equipment.

recycling

In the context of TP.MS 13.01T, this term comprises the process of SF6 gas recovery, reclaiming, storage, reuse, further treatment or disposal.

Reduced Security Notice

A notice issued by the grid operator in accordance with section 5.2 of the Grid Security Code. [GOSP glossary].

reduced volage operation

Control: For the thyristor pole only, the HVDC voltage can be manually reduced from 350 kV to 250 kV to:maintain HVDC transfer when high pollution on insulators is causing multiple line protection operations, increase converter Mvar demand, which helps control high a.c. system voltage. HVDC Protection: Automatically selected after a failed restart attempt at full voltage: Thristor pole (pole 2) voltage reduced from 350 kV to 250 kV, in 12 pulse operation, Mercury arc pole (pole 1) voltage reduced from 270 kV to 135 kV, by changing from 12 to 6 pulse operation. See also reduced voltage operation control.

reference electrode

An electrode the potential of which is accurately reproducible and serves as a basis of comparison in the measurement of other electrode potentials.

refurbishment

A term used for the drying out and tightening of windings, repair and replacement of faulty and substandard components, replacement of gaskets, treatment or replacement of oil and removal of corrosion and repainting.

regeneration

A proprietary process which uses re-refining and blending techniques to product insulating oil with essentially new oil characteristics.

regenerative braking

MFL x strength reduction (SRF) (SRF allows for variation in material properties, strength reductions in manufacturing processes, wear and other forms of degradation and variables in strength.).

regional operator

A person who carries out power system equipment operating and/or control functions to the requirements of the System Operator and Asset Owner.

regulator

An auto-transformer of one winding which is intended to be connected in series with a circuit in order to alter its voltage.

reinforced concrete

Means concrete containing more than 0.6% by volume of reinforcing, steel in the form of bar, rod or mesh.  Tensile forces within the concrete section are usually assumed to be resisted by the reinforcing steel.

REL

A statement transferring operational control of specified equipment for a specified purpose and time. A special case is contract release a long term release given for specified equipment to be operated in accordance with a contract agreement.

relative

The maximum amount of moisture (saturation or dew point) that can be absorbed into air varies greatly with temperature and absolute pressure. When air is at the saturation point, it is said to have humidity of 100%. The relative humidity of air at any time is the percentage of moisture contained in it as compared with the maximum amount it is capable of holding at the same temperature and pressure.

relay

Within the context of TP.CP 01.04, the word relay refers to stand alone protection relays, pre-assembled protection modules and pre-assembled protection cabinets.

relay (power systems)

A device designed to produce predetermined changes in one or more electrical output circuits when certain conditions are fulfilled in the electrical input circuits controlling the device.

Relay and Instrument diagram

The R&I diagram is a single line representation of all or part of a Transpower station showing relevant details of the primary equipment, overlaid with details of the protection functions and the instrumentation.

relay characteristic angle

For a measuring relay, the angle between the phasors representing two of the relay’s input energising quantities which is used for the declaration of the performance of the relay. [IEC 50 (446)].

release

A statement transferring operational control of specified equipment for a specified purpose and time. A special case is contract release a long term release given for specified equipment to be operated in accordance with a contract agreement.

release return

A statement made that the control of previously released equipment is returned.

reliability

The failure rate, e.g. the number of failures per year based on experience over a long time period, e.g. 10 years or more.

remote

Away from equipment, either in a control room or off site.

remote earth

The centre of the planet, or such other realistic distance, that the voltage rise at the position due to an earth fault is not measurable between that position and a more remote position.

Remote Operated Vehicle

An unmanned submersible.

remote site supervisor

The employee in charge of work party members working remote from the transmission circuit access permit recipient.

remote terminal unit

The processor at the outstations of a SCADA system. It transmits or receives data to or from an area operating centre or service centre.

remotely controlled station

A usually unattended station which is controlled by means of SCADA.

removed from service

See operational states.

repair time

The time duration between occurrence of a permanent fault on a circuit and completion of repairs.

replacement criteria

The mechanical condition reached by a hanger bracket whereby refurbishment or replacement is required to reinstate its original design strength requirement. Refer TP.SS 02.17.

reportable accident

An occurrence that shall be reported to the relevant asset owner which caused "Serious Harm" as defined by the Health And Safety In Employment Act, Section 2 and Section 2(4), or "Serious Injury" as defined by the Electricity Act, Section 16(2). Note: See also SR-EI Rule 311. [Health and Safety in Employment Act, and Electricity Act].

reportable defect

Any defect that is not expected given normal wear and tear or deterioration, or where a prescribed limit or tolerance has been reached which is not rectifiable during scheduled periodic servicing and maintenance, is a reportable defect.

required carryover (communications)

The period of carryover time required for a particular site.

required line life

The length of time the line is required to stay in service without any upgrading to meet transmission requirements. This information will be provided by the divisional office on request.

required reserve

The period of carryover time required for a particular site.

residual current

The fault current to earth - equal to three times the zero sequence current (I0).

residual current protection device

A device that senses a current imbalance as a result of earth leakage from that circuit and will disconnect that circuit when the imbalance exceeds a predetermined level.

residual voltage

This is the bectorial sum of the phase to earth voltages at any point on the system. As the positive and negative sequence voltages sum to zero, it is the sum of the zero sequence voltages. It is commonly measured by using 3 single phase voltage transformers connected in earthed-star/broken-delta.  The output voltage equals the residual votage at that point on the system.

residual voltage (arresters)

The voltage that appears between the line and earth terminals of a surge arrester during the passage of discharge current.

resistor

An electrical resistance of specified value used to control the discharge of fault currents to earth. These are air cooled and in the case of the two types currently used by Transpower, have been fabricated from stainless steel sheet.

resource consent

A consent to use land, air or water granted by the local government under the Resource Management Act. The consent usually imposes limits to that use.

restart

The HVDC equivalent of auto reclose for ac transmission circuits.

restoration (of equipment)

The action of reconnecting to the power system equipment that has been manually or automatically removed from service during a grid emergency.

restricted area

An area under the control of the operator containing hazards to personal safety or where work will present a risk to the security of the power system. Access is controlled by the issue of an entry approval.

restrike (circuit-breaker)

A resumption of current between the main contacts of a circuit-breaker during a breaking operation with an interval of zero current for more than a quarter-cycle of power frequency.

restrike time

Is time for lamps to reach full light output when the lamp is switched off and then switched on immediately.

return period

Means the statistical return period of a weather-related event, load or load effect.

review panel

the group of people appointed to examine a near-final draft of the standard to check for accuracy, compatibility with other standards, contractual, legislative and commercial impact.

RFS

A declaration made by an operator to the service centre. It indicates that an item of equipment which is released can be returned to the operational control of the service centre, that is the release can be terminated.

RG

Resistive Glaze.

ring main unit

Modular extendable metal-clad switchgear designed primarily for distribution applications up to 11 kV, incorporating fused switch, isolating switch, or circuit-breaker compartments. The circuit-breakers are vacuum or SF6 filled interrupter bottles and are non-withdrawable.

risk

The effect of uncertainty on objectives. In the context of safety and health, risk is the combination of the likelihood and consequence of events with adverse safety outcomes.

risk of trip (R/T)

An operating condition where there is a possibility of equipment tripping or HVDC blocking, resulting from work being done on or near power system equipment.

risk owner

Is a person or entity with the accountability and authority to manage a risk (ISO31000).

road

Means a public thoroughfare ordinarily used by motor vehicles.

Rochester TR

A proprietary TR which Transpower has standardised on. The TR is from the Rochester TR100 series recorders and has either 32/64 (TR132), 16/32 (TR116) or 8/16 (TR108) analogue and digital inputs respectively. Most sites will have the TR132 installed.

Rogers Ratio

A method for diagnosing the condition of a transformer or a type of fault by the use of combustible gas ratios.

ROV

An unmanned submersible.

roving operator

An operator carrying out operating duties at more than one station under the direction of the area operator.

RPC

A control system which monitors and controls reactive power flows to ensure system voltages remain within minimum and maximum limits. See also "not available to the reactive power control".

RTU

The processor at the outstations of a SCADA system. It transmits or receives data to or from an area operating centre or service centre.

RTV

Room Temperature Vulcanised.

ruling span

Also known as the equivalent span or the mean effective span (MES), is defined as the level dead-end span whose tension represents the tension in every span of a series of suspension spans under teh same loading conditions.

run up time

Is the time for lamps to reach full light outputs when switched on.

run-up

The process of bringing rotating machinery up to operating speed from being stationary.

runbacks

runbacks

running earths

A portable device designed to connect a moving conductor or wire rope, or both, to an electrical earth. These devices are normally placed on the conductor or wire rope adjacent to the pulling and tensioning equipment located at either end of a sag section. It is primarily used to provide safety for personnel during construction or reconstruction operations.

running machine

An alternator or synchronous condenser that is running at synchronous speed.

running voltage

The voltage at the terminals of a running machine, or of a part of the power system to which another part is to be paralleled.

rupture disk

A protective device for relieving excess pressures in enclosed containers (e.g. transformers, metal-enclosed switchgear, pressure vessels or air compressors) consisting of a thin disk of corrosion resisting metal, graphite or polycarbonate carefully controlled as to thickness. The disk is designed to burst, giving a large opening for the rapid release of pressure. Also known as burst disk, rupture disk.