Download Unit Number- 2460887

-SQA-SCOTTISH QUALIFICATIONS AUTHORITY
HIGHER NATIONAL UNIT SPECIFICATION
GENERAL INFORMATION
-Unit Number-
2460887
-Superclass-
XK
-Title-
SINGLE AND DOUBLE ENERGY TRANSIENTS
-----------------------------------------DESCRIPTIONGENERAL COMPETENCE FOR UNIT: Applying basic theory to the analysis of
single energy electric circuit transients.
OUTCOMES
1.
evaluate the transient responses of a series circuit under d.c. conditions;
2.
evaluate the transient responses of a series circuit under a.c. conditions;
3.
analyse and test the operation of a series circuit under specified
conditions.
4.
describe the performance of an RLC series circuit under d.c. conditions
CREDIT VALUE:
1 HN Credit
ACCESS STATEMENT: Access to this unit is at the discretion of the centre.
However, it would be beneficial if the candidate had working knowledge of
complex numbers and exponential operators. This may be evidenced by
possession of HN units:
2460877 Single Phase AC Networks
2660027 Transmission Lines
or similar qualifications or experience.
----------------------------------------For further information contact: Committee and Administration Unit, SQA,
Hanover House, 24 Douglas Street, Glasgow G2 7NQ.
Additional copies of this unit may be purchased from SQA (Sales and Despatch
section). At the time of publication, the cost is £1.50 (minimum order £5.00).
Unit No. 2460887
Continuation
HIGHER NATIONAL UNIT SPECIFICATION
STATEMENT OF STANDARDS
UNIT NUMBER:
2460887
UNIT TITLE:
SINGLE AND DOUBLE ENERGY TRANSIENTS
Acceptable performance in this unit will be the satisfactory achievement of the
standards set out in this part of the specification. All sections of the statement of
standards are mandatory and cannot be altered without reference to SQA.
OUTCOME
1.
EVALUATE THE TRANSIENT RESPONSES OF A SERIES
CIRCUIT UNDER D.C. CONDITIONS
PERFORMANCE CRITERIA
(a)
(b)
(c)
(d)
Correctly explain the responses of a series circuit under the
application and removal of a D.C. supply.
Correctly evaluate the circuit time constant.
Correctly evaluate the voltages and current at various times in a
series circuit.
Correctly evaluate the time taken to attain various voltages and
currents in a series circuit.
RANGE STATEMENT
Series circuit types: resistor capacitor; resistor inductor.
Evaluated parameters: time constant; capacitor voltage; resistor voltage;
inductor voltage; initial current; instantaneous current; steady state current; time.
EVIDENCE REQUIREMENTS
Written and graphical evidence of the candidate’s knowledge and understanding
of the responses of a series circuit to the application and removal of a D.C.
supply.
Calculations of time constant, voltages and current for a minimum of two time
values as detailed in performance criteria (b) and (c).
A minimum of two calculations of time as detailed in performance criterion (d).
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Unit No. 2460887
Continuation
OUTCOME
2.
EVALUATE THE TRANSIENT RESPONSES OF A SERIES
CIRCUIT UNDER A.C. CONDITIONS
PERFORMANCE CRITERIA
(a)
(b)
Correctly explain the responses of a series circuit under the
application of an a.c. supply.
Correctly evaluate the voltages and currents at various times and
switching angles in a series circuit.
RANGE STATEMENT
Series circuit types: resistor inductor; resistor capacitor.
Evaluated parameters: capacitor voltage; resistor voltage; inductor voltage;
initial current; steady state current; transient current; instantaneous current.
EVIDENCE REQUIREMENTS
Written and graphical evidence of the candidate’s knowledge and understanding
of the responses of a series circuit under a.c. conditions.
Calculations of voltages and currents for a minimum of two time values and two
switching angles.
OUTCOME
3.
ANALYSE AND TEST THE OPERATION OF A SERIES CIRCUIT
UNDER SPECIFIED CONDITIONS
PERFORMANCE CRITERIA
(a)
(b)
(c)
Explanation of the operation of an R-C series circuit under
specified conditions is correct.
Transient responses of a series circuit are correctly determined by
measurement.
A report on the test of a series circuit under specified conditions is
concise and complete.
RANGE STATEMENT
Circuit test: voltage measurements; current measurements; time measurements.
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Unit No. 2460887
Continuation
EVIDENCE REQUIREMENTS
Written and graphical evidence in the form of a report of the candidate’s
knowledge and understanding of the operation of an R-C series circuit under
specified conditions as detailed in performance criteria (a) - (c).
OUTCOME
4.
DESCRIBE THE PERFORMANCE OF AN RLC SERIES CIRCUIT
UNDER D.C. CONDITIONS
PERFORMANCE
(a)
(b)
Correctly describe that for a double energy transient to occur, the
network must contain inductance L and capacitance C.
Correctly explain the response for an RLC series circuit under the
application of a D.C. supply.
RANGE STATEMENT
Responses: undamped; critically damped; overdamped.
EVIDENCE REQUIREMENTS
Written and/or oral evidence of the candidate’s knowledge and understanding of
the performance of an RLC series circuit under d.c. conditions.
MERIT To gain a pass in this unit, a candidate must meet the standards set out
in the outcomes, performance criteria, range statements and evidence
requirements.
To achieve a merit in this unit, a candidate must demonstrate a superior or more
sophisticated level of performance. This may be demonstrated by:
(i)
(ii)
analytical skills;
logical presentation of work.
-----------------------------------------
ASSESSMENT
In order to achieve this unit, candidates are required to present sufficient
evidence that they have met all the performance criteria for each outcome within
the range specified. Details of these requirements are given for each outcome.
The assessment instruments used should follow the general guidance offered by
the SQA assessment model and an integrative approach to assessment is
encouraged. (See references at the end of support notes).
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Unit No. 2460887
Continuation
Accurate records should be made of the assessment instruments used showing
how evidence is generated for each outcome and giving marking schemes
and/or checklists, etc. Records of candidates’ achievements should be kept.
These records will be available for external verification.
SPECIAL NEEDS
Proposals to modify outcomes, range statements or agreed assessment
arrangements should be discussed in the first place with the external verifier.
 Copyright SQA 1997
Please note that this publication may be reproduced in whole or in part for
educational purposes provided that:
(i)
(ii)
no profit is derived from the reproduction;
if reproduced in part, the source is acknowledged.
5
Unit No. 2460887
Continuation
HIGHER NATIONAL UNIT SPECIFICATION
SUPPORT NOTES
UNIT NUMBER:
2460887
UNIT TITLE:
SINGLE AND DOUBLE ENERGY TRANSIENTS
SUPPORT NOTES: This part of the unit specification is offered as guidance.
None of the sections of the support notes is mandatory.
NOTIONAL DESIGN LENGTH: SQA allocates a notional design length to a unit
on the basis of time estimated for achievement of the stated standards by a
candidate whose starting point is as described in the access statement. The
notional design length for this unit is 40 hours. The use of notional design length
for programme design and timetabling is advisory only.
PURPOSE The purpose of this unit is to provide an understanding of single and
double energy transients for candidates who will be studying electrical principles
in later stages of their course.
CONTENT/CONTEXT This unit is designed to:
(a)
(b)
develop competence in applying basic theory to the analysis of single and
double energy electric circuit transients;
provide underpinning knowledge to support HN Units specialising in
electrical, electronic and telecommunication engineering.
Corresponding to outcomes 1-3:
It is recommended that the candidate will:
Outcome 1
Evaluate the transient responses for a series circuit under d.c. conditions.
Series circuit types: RC charging; RL charging; RC discharging; RL discharging;
associated voltage/time and current/time characteristics; associated equations;
evaluative parameters; time constant; capacitor, resistor voltage; inductor,
resistor voltage; initial, instantaneous and steady state current; time.
Outcome 2
Evaluate the transient responses for a series circuit under a.c. conditions.
Series circuit types; RC charging; RL charging; transient, steady state and
instantaneous current; associated voltage and current against time
characteristics for various switching angles; associated equations.
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Unit No. 2460887
Continuation
Evaluated parameters: capacitor resistor voltage; inductor, resistor voltage;
initial, steady state, transient and instantaneous current.
Outcome 3
Analyse and test the operation of an R-C series circuit under d.c. or a.c.
conditions.
Circuit operation: explanation of transient responses; use of current formulae;
use of equipment (or computer simulation package).
Circuit test: voltage, current, time measurements; recording of transient
responses.
Report: circuit operation, measurement results and characteristics under
specified conditions (using relevant equipment or computer simulation package).
Outcome 4
Describe the performance of an RLC series circuit under d.c. conditions.
Responses: damped, critically damped, overdamped, associated current against
time characteristics for the four typical responses.
APPROACHES TO GENERATING EVIDENCE This unit should be taught within
a classroom environment where access to a laboratory or computers with
relevant simulation packages should be readily available.
ASSESSMENT PROCEDURES
Outcome 1
Structured questions using supplied mathematical formulae and circuit diagrams.
Outcome 2
Structured questions using supplied mathematical formulae and circuit diagrams.
Relevant computer simulation packages could be used for graphs.
Outcome 3
Structured questions for performance criterion (a) and for performance criteria
(b) and (c) a report on a practical circuit test or computer simulation for a RC
series circuit.
Outcome 4
Structured questions for PCs (a) and (b).
packages could be used for graphs.
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Relevant computer simulation
Unit No. 2460887
Continuation
PROGRESSION This unit may lead on to any of the following HN units:
3471547 Electrical and Magnetic Fields
2660027 Transmission Lines
REFERENCES
1.
2.
3.
4.
Guide to unit writing.
For a fuller discussion on assessment issues, please refer to SQA’s
Guide to Assessment.
Information for centres on SQA’s operating procedures is contained in
SQA’s Guide to Procedures.
For details of other SQA publications, please consult SQA’s publications
list.
 Copyright SQA 1997
Please note that this publication may be reproduced in whole or in part for
educational purposes provided that:
(i)
(ii)
no profit is derived from the reproduction;
if reproduced in part, the source is acknowledged.
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