24691 version 1
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Demonstrate knowledge of a.c generators for hydro-electric generation
Level
4
Credits
15
Purpose
People credited with this unit standard are able, for ac generators for hydroelectric generation, to: describe the components; demonstrate knowledge of
the principles of operation; demonstrate knowledge of excitation systems;
and demonstrate knowledge of protection systems.
Subfield
Electricity Supply
Domain
Electricity Supply - Power System Management
Status
Registered
Status date
19 May 2008
Date version published
19 May 2008
Planned review date
31 December 2013
Entry information
Open.
Accreditation
Evaluation of documentation and visit by NZQA and
industry.
Standard setting body (SSB)
Electricity Supply Industry Training Organisation
Accreditation and Moderation Action Plan (AMAP) reference
0120
This AMAP can be accessed at http://www.nzqa.govt.nz/framework/search/index.do.
Special notes
1
This unit standard is intended for, but not restricted to, workplace assessment. The
range statements within the unit standard can be applied according to enterprise
specific equipment, procedures and processes.
2
Safety of personnel and plant must be a priority throughout the assessment. If the
safety requirements are not met the assessment must stop.
 New Zealand Qualifications Authority 2016
24691 version 1
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3
Performance and work practices in relation to the elements and performance criteria
must comply with all current legislation, especially: the Electricity Act 1992, and any
regulations and codes of practice recognised under that statute; the Health and
Safety in Employment Act 1992; and the Resource Management Act 1991.
Electricity supply industry codes of practice and documented industry procedures
include the Safety Manual – Electricity Industry (SM-EI) (2004) Wellington: Electricity
Engineers’ Association. A full list of current legislation and industry codes is
available from the Electricity Supply Industry Training Organisation, PO Box 1245,
Hamilton.
4
The phrase in accordance with industry requirements is implicit in all elements and
performance criteria in this unit standard.
5
Industry requirements include all the documented workplace policies, procedures,
specifications, business and quality management requirements relevant to the
workplace in which assessment is carried out.
Elements and performance criteria
Element 1
Describe the components of a.c. generators for hydro-electric generation.
Performance criteria
1.1
The components of a.c. generator stators for hydro-electric generation are
described.
Range
1.2
The components of a.c. generator salient pole rotors for hydro-electric
generation are described.
Range
1.3
includes but not limited to – horizontal or vertical configuration, stator
core, steel laminations, insulation, insulation classification,
ventilation ducts, clamping, stator windings, multi-turn and single bar
type, lap or wave connection, distribution factor, cooling systems,
open or closed ventilation, neutral star connection, earthing
transformer, earthing resistor or reactor, voltage transformers,
current transformers.
rotor spider, rim, pole construction, method of pole attachment, field
windings, damper windings, cooling fans, slip rings, brush
composition, brush holders, speed sensing, permanent magnet
generator (PMG), speed wheel, brakes and brake track.
The components of bearings for a.c. generators for hydro-electric generation
are described.
Range
pedestal bearings, thrust bearings, guide bearings, construction and
composition of bearing surfaces, cooling, lubrication, high pressure
oil injection, jacking, bearing and shaft currents, shaft brush.
 New Zealand Qualifications Authority 2016
24691 version 1
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Element 2
Demonstrate knowledge of the principles of operation of a.c. generators for hydro-electric
generation.
Performance criteria
2.1
The operating limitations of hydro-electric generators are described in
accordance with manufacturers’ specifications.
Range
2.2
Hydro-electric generator operation is described in accordance with
manufacturers’ specifications.
Range
2.3
capability limits, Volts Amps (VA) rating, full load rated power factor,
prime mover power, rotor current, stator current, stability limits,
load/rotor angle, pole slipping, stator voltages, runaway speed,
electrical and mechanical stresses, vibration.
electro-magnetic induction, armature reaction, iron and copper
losses, eddy current losses, windage losses, leakage flux, Volts
Amps Reactive (VAR), sharing/transformer reactance, transmission
line loading effect on voltage, braking-friction, dynamic.
Control of hydro-electric generators is described.
Range
operating point, synchronising, tail water depressed/synchronous
condenser operation, spinning reserve, reactive power VAR control.
Element 3
Demonstrate knowledge of excitation systems for a.c. generators for hydro-electric
generation.
Performance criteria
3.1
Components of a rotating excitation system used in an a.c. generator for hydroelectric generation are described.
Range
3.2
pilot exciter, main exciter, brushless excitation, Automatic Voltage
Regulator (AVR), amplidyne, field circuit breaker, rotor field
discharge.
Components of a static excitation system used in an a.c. generator for hydroelectric generation are described.
Range
thyristor rectifiers, excitation supply transformer, AVR,
standby/current regulator, follow-up unit, null balance meter, field
circuit breaker, rotor field discharge, field flashing, VAR
droop/sharing, limiters, Proportional-Integral Derivative (PID) control,
power system stabiliser.
 New Zealand Qualifications Authority 2016
24691 version 1
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3.3
Labelled block diagrams are constructed showing all components.
Element 4
Demonstrate knowledge of protection systems for a.c. generators.
Performance criteria
4.1
The purpose and function of protection relays in terms of relay operation is
described.
Range
4.2
The purpose and function of overcurrent and earth fault relays is described.
Range
4.3
Stator phase to phase and phase to earth faults, stator fault
overcurrent, undervoltage, overvoltage, stator overtemperature,
stator fire, negative phase sequence current, generator differential
protection, overall differential protection, reverse power, overspeed,
rotor earth fault, resistance temperature detectors.
two or three phase faults, inverse-time, overcurrent relays.
The purpose and function of differential protection is described.
Range
currents, discharge of fire extinguishing medium.
Please note
Providers must be accredited by NZQA, or an inter-institutional body with delegated
authority for quality assurance, before they can report credits from assessment against
unit standards or deliver courses of study leading to that assessment.
Industry Training Organisations must be accredited by NZQA before they can register
credits from assessment against unit standards.
Accredited providers and Industry Training Organisations assessing against unit standards
must engage with the moderation system that applies to those standards.
Accreditation requirements and an outline of the moderation system that applies to this
standard are outlined in the Accreditation and Moderation Action Plan (AMAP). The
AMAP also includes useful information about special requirements for organisations
wishing to develop education and training programmes, such as minimum qualifications for
tutors and assessors, and special resource requirements.
Comments on this unit standard
Please contact the Electricity Supply Industry Training Organisation info@esito.org.nz if
you wish to suggest changes to the content of this unit standard.
 New Zealand Qualifications Authority 2016