Unit of competency: UETTDRTS23A - Conduct evaluation of power system substation faults


Retrieved from: https://training.gov.au/Training/Details/UETTDRTS23A  13/02/2020


Unit Descriptor

Unit Descriptor 

1) Scope: 


1.1) Descriptor 


This Competency Standard Unit covers the procedure in evaluating power system incidents by following a process of downloading event and disturbance record information from protection relays. This includes interpreting such items as, alarms, relay targets, relay settings, event records, disturbance records and sequence of events records. It also encompasses the evaluation and or investigation of relay operation, relay schemes functionality and relay settings.

Application of the Unit

Application of the Unit 



This competency standards unit is intended to apply to any recognised development program that leads to the acquisition of a formal award at AQF level 6 or higher.



Licensing/Regulatory Information

License to practice 



The skills and knowledge described in this unit may require a licence/registration to practice in the work place subject to regulations for undertaking of electrical work. Practice in workplace and during training is also subject to regulations directly related to Occupational Health and Safety, electricity/telecommunications/gas/water industry safety and compliance, industrial relations, environmental protection, anti discrimination and training. Commonwealth, State/Territory or Local Government legislation and regulations may exist that limits the age of operating certain equipment.


Prerequisite Unit(s) 





Granting of competency in this unit shall be made only after competency in the following unit(s) has/have been confirmed.

Where pre-requisite pathways have been identified. All competencies in the Common Unit Group must be have been completed plus all the competencies in one (1) of the identified Pathway Unit Group(s):

Common Unit Group


Unit Code

Unit Title



Use engineering applications software on personal computers



Apply Occupational Health and Safety regulations, codes and practices in the workplace



Fabricate, assemble and dismantle utilities industry components



Solve problems in d.c. Circuits



Use drawings, diagrams, schedules, standards, codes and specifications



Compile and produce an energy sector detailed report



Provide engineering solutions for problems in complex multiple path circuits problems



Provide solutions to basic engineering computational problems



Solve problems in electromagnetic devices and related circuits



Solve problems in electromagnetic devices and related circuits



Provide engineering solutions to problems in complex polyphase power circuits



Apply sustainable energy and environmental procedures



Working safely near live electrical apparatus



Implement and monitor the power system organisational OHS policies, procedures and programs



Implement and monitor the power system environmental and sustainable energy management policies and procedures


Literacy and numeracy skills 



Participants are best equipped to achieve this unit if they have reading, writing and numeracy skills indicated by the following scales. Description of each scale is given in Volume 2, Part 3 “Literacy and Numeracy”









Employability Skills Information

Employability Skills 



The required outcomes described in this unit of competency contain applicable facets of Employability Skills. The Employability Skills Summary of the qualification in which this unit of competency is packaged will assist in identifying Employability Skill requirements.

Elements and Performance Criteria Pre-Content

6)  Elements describe the essential outcomes of a competency standard unit

Performance Criteria describe the required performance needed to demonstrate achievement of the element. Assessment of performance is to be consistent with the Evidence Guide.

Elements and Performance Criteria




Plan for the evaluation of power system events


OHS practices/procedures and Environmental and sustainable energy procedures, which may influence the evaluation of power system failures, are reviewed and determined.



Purpose of the evaluation of power system events, are established after data is analysed and expected outcomes of the work are confirmed with the appropriate personnel.



Organisational established procedures on policies and specifications for the evaluation of power system failures are obtained or established with the appropriate personnel.



Testing procedures are discussed with/directed to the appropriate personnel in order to ascertain the project brief.



Testing parameters are established from organisational established procedures on policies and specifications.



Equipment/tools and personal protective equipment are selected based on specified Performance Criteria and established procedures.



Work roles and tasks are allocated according to requirements and individuals’ competencies.



Work is prioritised and sequenced for the most efficient/effective outcome, completed within an acceptable timeframe to a quality standard and in accordance with established procedures.



Liaison and communication issues with other/authorised personnel, authorities, clients and land owners are resolved and activities coordinated to carry out work.



Risk control measures are identified, prioritised and evaluated against the work schedule.



Relevant work permits are secured to coordinate the performance of work according to requirements and/or established procedures.


Carry out the evaluation of power system events


Circuit/systems modelling is used to evaluate alternative proposals as per established procedures.



OHS and sustainable energy principles, functionality and practices to reduce the incidents of accidents and minimise waste are incorporated into the project in accordance with requirements and/or established procedures.



Following evaluation of power system events, decisions are made on the basis of safety and effective outcomes according to requirements and/or established procedures.



Mathematical and /or engineering models of the evaluation of power system events are used to analyse the effectiveness of the finished project as per requirements and established procedures.



Technical advice is given regarding potential hazards, safety risks and control measures so that monitoring and preventative action can be undertaken and/or appropriate authorities consulted, where necessary, in accordance with requirements and established procedures.



Essential knowledge and associated skills are applied to analyse specific data and compare it with compliance specifications to ensure completion of the project within an agreed timeframe according to requirements.



Testing of power system is undertaken according to requirements and established procedures.



Work teams/groups are arranged/coordinated/evaluated to ensure planned goals are met according to established procedures.



Solutions to non-routine problems are identified and actioned, using acquired essential knowledge and associated skills, according to requirements.



Quality of work is monitored against personal performance agreement and/or established organisational and professional standards.



Strategic plans are developed incorporating organisation initiatives as per established procedures.


Complete the evaluation of power system events


Final evaluation of all relevant data pertaining to the power system event is undertaken to ensure the recommendations comply with all requirements and include all specifications and documentations needed to complete the project.



Appropriate personnel are notified of completion and reports and/or completion documents are finalised/commissioned.



Reports and/or completion documents are submitted to relevant personnel/organisations for approval and, where applicable, statutory or regulatory approval.



Approved copies of the evaluation of power system event documents are issues and records are updated in accordance with established procedures.

Required Skills and Knowledge


8)  Essential Knowledge and Associated Skills (EKAS): This describes the essential skills and knowledge and their level, required for this unit.

Evidence shall show that knowledge has been acquired of conducting evaluation of power system faults within a substation.

All knowledge and skills detailed in this unit should be contextualised to current industry practices and technologies.

KS01-TTS23A Power system substation faults evaluation

Evidence shall show an understanding of power system substation faults evaluation to an extent indicated by the following aspects:

T1 OHS enterprise responsibilities encompassing:

·         Provisions of relevant health and safety legislation

·         Principles and practice of effective occupational health and safety management

·         Management arrangements relating to regulatory compliance

·         Enterprise hazards and risks, control measures and relevant expertise required

·         Characteristics and composition of workforce and their impact on occupational health and safety management

·         Relevance of enterprise management systems to occupational health and safety management

·         Analysis of working environment and design of appropriate occupational health and safety management systems

·         Analysis of relevant data and evaluation of occupational health and safety system effectiveness

·         Assess resources to establish and maintain occupational health and safety management systems.

T2 Power distribution network documentation encompassing:

·         Requirements for the use of manuals, system diagrams/plans and drawings and for plans such as work method statements for the control of OHS risks

·         Types and application of power distribution network documentation drawings and documents - wiring and schematic diagrams, drawings and switching symbols, mechanical drawings dealing with the power distribution network, project charts, schedules, graphs, technical manuals and catalogues, instruction/worksheets sheets.

·         Interpretation of different diagrams and documentation on LV and HV systems - overhead distribution extensions, underground distribution extensions, distribution substation, street lighting system

T3 Measurements and the interpretation and analysis of those measurements related to the plant and/or equipment type encompassing:

·         Type of measurements - timing, current, voltage, capacitance, inductance, impedance, phase angle, phase shift, resistance, dielectric dissipation factor, frequency, polarisation index, ratio, vector group, temperature

·         Interpretation and analysis the use of techniques - digital comparison of data, extrapolation, use of graphs and charts, statistics and tables, mathematical calculation of expected values and comparison with manufacturers data and measurements

·         Techniques in the processes involved in follow-up actions and recommendations resulting from analysis and interpretation of results and measurements.

T4 System components and layouts encompassing:

·         Distribution system layouts - overhead/underground, urban/rural, HV customers, high rise building systems, three phase lines, single phase lines, SWER systems, spur, parallel and ring systems, typical substation types.

·         Transmission system layouts - lines, buses, transformers and cables, line/bus layouts including single, double, ring and breaker and half systems, HV crossing methods.

T5 Calculation of fault levels encompassing:

·         Calculation of fault levels in symmetrical and asymmetrical fault conditions - types of faults, interconnected and radial systems, symmetrical components, representation of voltages and currents, sequence impedances of system plant, calculation/determination of sequence impedance networks, determination of operative sequence impedances, fault or arc impedances, first approximation techniques

·         Interrupting device capabilities - determination of fault current breaking capability and let through energy capability of fuses and circuit breakers, DC offset and transient condition effects

T6 Protection system types encompassing:

·         Requirements of a protection scheme - relationship to primary system design, purpose of protection, safety of persons, protection of plant, system instability, system break up, loss of customers, loss of revenue, protection zones, restricted schemes, unrestricted schemes, duplicate protection, local backup protection, remote backup protection, selectivity, discrimination, stability, sensitivity, reliability

·         Components of a protection scheme - current transformers, potential transformers, summation current transformers, interposing transformers, multitapped transformers, all-or-nothing relays, induction relays, balanced beam relays, directional relays, biased relays, solid state relays, microprocessor based relays, gas relays, thermal sensors, hardwired communication, powerline carriers systems, microwave systems, fibre optic systems, need for isolation, need for interfacing

·         Protection applied to buses - overload, differential, earth leakage, structure leakage, combined schemes, protection overlap

·         Protection applied to transformers - biased differential, gas, winding temperature, oil temperature

·         Protection applied to single/radial lines - overcurrent, earth leakage, slow earth leakage, distance, auto reclose, sectionalising, over voltage

·         Protection applied to interconnected lines - overcurrent, pilot wire, directional, directional overcurrent, current differential, phase comparison, current comparison, distance, impedance, admittance, offset

T7 Detailed operation and setting of discrete protection systems encompassing:

·         Earth fault protection - master earth leakage schemes, sensitive earth fault relays and schemes, residual earth fault scheme, core balance earth fault scheme, frame/structure earth leakage scheme, time graded discrimination, backup protection

·         Overcurrent protection - feeder overcurrent protection, instantaneous overcurrent schemes, inverse timed overcurrent schemes, types and location of components of an overcurrent scheme, CT summation, time graded discrimination, backup protection

·         Alarms and controls - auxiliary relays, voltage regulating relays, line drop compensation, gas relay types, gas relay scheme operation and setting, over temperature schemes

T8 Detailed operation of interdependent protection systems encompassing:

·         Overcurrent and earth leakage schemes including intertripping, interlocking and blocking - logic mapping, master control, electromechanical, electronic, shading coils

·         Pilot wire, phase comparison - opposed voltage schemes, circulating current schemes, location of components of a scheme, pilot supervisory techniques,

·         Load shedding, voltage control, parallel operation, load rejection

·         Busbar Protection and CB failure protection

·         Reclose systems - applications, single shot, multishot, blocking schemes, synchronisation checking.

T9 Detailed operation of complex protection systems encompassing:

·         Distance - characteristics, electromechanical, electronic, impedance, mho, offset mho, switched schemes, non-switched schemes, blocking schemes, bus zone

·         Differential, transformer differential, bus overcurrent - principles, feeder protection, transformer protection, bias systems, harmonic restraint, CT connections, bus protection, low impedance schemes, high impedance schemes, bus overcurrent schemes, generator protection, CT connections, special considerations, digital systems

·         Types of revenue metering

·         Applications of SCADA

·         Complex protection systems for communications

·         Harmonic control

·         Point on wave switching

Software/Hardware Used