1. Session 11: Application of Australian Standards to HV Switchgear Routine Testing
Session 11:
Application of Australian Standards to HV Switchgear
Routine Testing
Gabriel Ojeah
Consulting Engineer, Gadian Electrical Engineering Services
Abstract:
Though the AS 62271 series standards have been around, the existing AS
2067-2008: Substations and High Voltage Installations Exceeding 1 kV ac does
not explicitly mention the AS 62271 series standards as the Standards to apply
when dealing with high voltage switchgear. This has now been addressed in
the next version of AS 2067 (expected to be released in 2015) by updating
Clause 5.4.1 to include “Factory-built, type-tested high voltage switchgear shall
be manufactured and tested in accordance with relevant standards such as AS
62271.1, AS 62271.200, AS 62271.201 and AS 62271.203.”
This paper will examine the application of AS 62271.200-2005 to routine testing
of metal enclosed switchgear above 1kV and up to 52 kV.
Introduction
Standards are put in place for various purposes including specifying minimum
design requirements, specifying legislative requirements, providing purchasing
specifications, providing technical conditions for contracts, providing guidance,
etc.
On their own, Standards have no legal status and no requirement for
compliance. However, when Standards are called up in government legislation,
they become mandatory and can be subject to the scrutiny of the courts. Under
the Western Australian Electricity Act 1945 for instance, WA Electricity Supply
Standards & System Safety Regulations 2001 calls up AS 2067 in Schedule 3 -
Standards and codes containing obligatory provisions for network operators.
AS 2067 then calls up AS 62271.200 as the Standard according to which all
metal enclosed switchgear above 1kV and up to 52 kV shall be manufactured
and tested.
High Voltage Conference 2015 – IDC Technologies 1

2. Session 11: Application of Australian Standards to HV Switchgear Routine Testing
Basic Functions of Electrical Switchgear
The basic functions of electrical switchgear include control, protection and
isolation.
• Control: Mainly functional switching which makes it possible for voltage
supply to various loads to be switched on and off independently. Control
also includes emergency switching.
• Protection: Fast isolation of faulted circuits, thus offering protection for
equipment and personnel as well as aiding system security. Protection is
offered against faults such as overload, short circuit, overvoltage, etc.
• Isolation: Secure physical isolation of downstream circuits for
maintenance or other purposes so that such circuits can remain securely
disconnected from the energy source and made safe.
Main Components of Typical Switchgear Assembly
A typical switchgear assembly is shown in Figure 1. An assembly can be made
up of as many as 50 switchgear panels or more.
Figure 1: Typical Switchgear Assembly
The representation of a typical switchgear assembly on a single line diagram is
shown in Figure 2. This example shows two incomers and five feeders together
with a bus tie making up BUS A of the switchgear assembly. Through the bus
tie, BUS A is connected to BUS B which is similar to BUS A.
High Voltage Conference 2015 – IDC Technologies 2

3. Session 11: Application of Australian Standards to HV Switchgear Routine Testing
Figure 2: Single Line Diagram Representation of Typical Switchgear Assembly
Components of a typical switchgear panel include voltage transformers, earth
switch, disconnector, current transformers, circuit breaker, bus bars as well as
metering, protection and control devices. Components of a typical switchgear
panel are shown in Figure 3.
Figure 3: Typical Switchgear Panel
High Voltage Conference 2015 – IDC Technologies 3

4. Session 11: Application of Australian Standards to HV Switchgear Routine Testing
Applicable Standards for HV Switchgear Routine Tests
The draft Australian Standard 2067-2014 - Substations and High Voltage
Installations Exceeding 1 kV ac stipulates that factory-built, type-tested high
voltage switchgear shall be manufactured and tested in accordance with
relevant standards such as AS 62271.1, AS 62271.200, AS 62271.201 and AS
62271.203.
The rest of this paper will be devoted to applying Australian Standard
62271.200-2005 to routine testing of metal enclosed switchgear above 1kV and
up to 52 kV as well as applying relevant Australian Standards to routine testing
of the main switchgear components such as circuit breakers, voltage
transformers, current transformers, disconnectors and earth switches.
HV Switchgear Routine Tests Under AS 62271.200
The following routine tests are conducted under AS 62271.200;
Dielectric test on the main circuit (AS 62271.200 subclause 7.1)
Only short-duration power-frequency withstand voltage test is required and the
test is to be carried out in dry condition only.
With the continuity of the main circuit assured by closing the switching devices
(circuit breakers and disconnectors), the test voltage is applied to one phase at
a time with the other two phases earthed. Test duration is 1 minute and the test
is deemed successful if no disruptive discharge occurs.
Rate of increase of test voltage, test duration and acceptance criterion are
specified in subclause 6.3.1 of IEC 60060-1 (High-voltage test techniques –
Part 1: General definitions and test requirements. Requirements of the
measurement system are specified in IEC 60060-2 (High-voltage test
techniques – Part 2: Measuring systems)
The test voltages are given in Table 1a of AS 62271.1 (High-voltage switchgear
and controlgear - Part 1: Common specifications). An extract is shown below in
Table 1. The common values apply to phase-to-earth, and phase-to-phase
withstand while the values across the isolating distance apply where the
High Voltage Conference 2015 – IDC Technologies 4

5. Session 11: Application of Australian Standards to HV Switchgear Routine Testing
clearance between open contacts is designed to meet the functional
requirements for disconnectors.
Rated voltage
Ur
kV (rms value)
Rated short-duration power-frequency withstand voltage
Ud
kV (rms value)
Common value Across the isolating distance
3.6 10 12
7.2 20 23
12 28 32
17.5 38 45
24 50 60
36 70 80
52 95 110
Table 1: Power-Frequency Withstand Test Voltages Extracted from Table 1a of AS 62271.1
Test on auxiliary and control circuits (AS 62271.200 subclause 7.2)
This test is based on AS 62271.1 subclause 7.2 and consists of the following;
• Inspection of auxiliary and control circuits for verification of conformity
with circuit diagrams and wiring diagrams
• Functional tests
• Verification of protection against electric shock
• Dielectric tests
A visual inspection of the auxiliary and control circuits would include looking out
for such items as physical damage, quality of the individual components, quality
of the assembly, mounting, wiring termination, adequacy of terminal strips,
adequacy of cable ducts, protection of wiring from heat & sharp objects, etc.
The General Arrangement (GA) drawings are checked in detail against the
physical installation and updated as necessary. The Schematic drawings are
checked in in detail against the physical installation to verify continuity of the
physical wiring, cable numbers, wire numbers, device details, types of contacts,
functional correctness, etc. The Schematic drawings are updated to reflect as-
built condition.
High Voltage Conference 2015 – IDC Technologies 5

6. Session 11: Application of Australian Standards to HV Switchgear Routine Testing
Functional tests are conducted to verify the proper functioning of auxiliary and
control circuits in conjunction with the other parts of the switchgear. The
functional tests would include verification of voltage switching through individual
MCBs, mechanical/electrical operation of switching devices, status of switching
device auxiliary contacts, anti-pumping device operation, under-voltage relay
operation, reduced voltage operation of circuit breaker open & close coils, etc.
Verification of protection against electric shock is done by visual inspection to
ensure that metallic partitions and shutters provide protection against direct
contact with the main circuit. It also includes visual inspection to verify safe
access to auxiliary and control equipment that can be touched during normal
operation. Where protection against electric shock cannot be satisfactorily
verified through visual inspection, earthed metallic parts need to be checked for
continuity to the earthing point. The continuity test is conducted at 30 A dc with
a result of less than 0.1 Ω.
Dielectric test involves power-frequency voltage withstand tests at 1 kV for 1
second between the auxiliary and control circuits connected together as a
whole and the frame of the switchgear. For parts that are insulated from each
other during normal operation, if practicable, the test is also conducted between
each part and the other parts connected together and connected to the
switchgear frame. The dielectric test is considered to be successful if no
disruptive discharge occurs.
Measurement of the resistance of the main circuit (AS 62271.200
subclause 7.3)
Unlike the tests we have considered so far, AS 62271.1 is not applicable.
Rather, this test is subject to agreement between the manufacturer and the
user. If the agreement is to use AS 62271.1, the test is covered in subclause
7.3 which stipulates a dc test current of between 50 A and the rated current. It
also stipulates acceptable resistance as not exceeding 120% of the resistance
measured before the temperature-rise test during Type testing. If tests at lower
High Voltage Conference 2015 – IDC Technologies 6

7. Session 11: Application of Australian Standards to HV Switchgear Routine Testing
current yield high resistance, the test is to be repeated at a higher current as
close as possible to the rated current before this can be correctly diagnosed as
a bad contact.
Tightness Check (AS 62271.200 subclause 7.4)
Tightness check is based on leakage rate of the fluid (gas or liquid). This test is
based on AS 62271.1 subclause 7.4. Methods for measuring or calculating the
leakage are provided.
Design and Visual Checks (AS 62271.200 subclause 7.5)
The switchgear is checked to verify compliance with the purchase/design
specifications. A comprehensive checklist can be produced from the
information in subclause 5 (Design and construction) of this Standard.
Partial Discharge Measurement (AS 62271.200 subclause 7.101)
This test is subject to agreement between the manufacturer and the user. A
test procedure is provided in Annex B of this Standard.
Mechanical operation tests (AS 62271.200 subclause 7.102)
The switching devices are operated several times to ensure that they open and
close correctly within the specified limits of the supply voltage and pressure as
well as to ensure that the mechanical interlocks work properly. Withdrawable
parts are inserted and removed several times to verify satisfactory operation.
The specified number of operations for mechanical operations tests is 5.
Pressure tests of gas-filled compartments (AS 62271.200 subclause
7.103)
Gas-filled compartment excluding those rated 50 kPa (relative pressure) and
below are tested for 1 min at 130% of the design pressure.
High Voltage Conference 2015 – IDC Technologies 7

8. Session 11: Application of Australian Standards to HV Switchgear Routine Testing
Tests of auxiliary electrical, pneumatic and hydraulic devices (AS
62271.200 subclause 7.104)
The electrical, pneumatic and other interlocks together with control devices that
have a predetermined sequence of operation are tested five times in
succession at the most unfavourable limit (upper or lower) of the auxiliary
supply. An example would be attempting to close a circuit breaker with the
close release coil disabled and making another attempt with the close release
coil energised at a voltage just above the lower limit. This test differs from
functional test because it is conducted repeatedly under adverse conditions.
The test is considered to be satisfactory if the auxiliary device;
• Operates properly without adjustments between repeated operations
• Remains in good operating condition after the tests
• The ease of operation is practically the same before and after the tests.
Tests after erection on site (AS 62271.200 subclause 7.105)
After erection, the switchgear is tested to check correct operation.
The following tests are required;
• Main circuit short-duration power-frequency withstand voltage test at 80
% of the values indicated in subclause 7.1 provided the test has been
done at full test voltage during the factory routine test.
• Tightness tests as specified in subclause 7. 4 are conducted.
• For gas-filled compartments which are filled onsite, measurement of fluid
condition as specified in subclause 7.106 is conducted after filling.
The same operational tests conducted during the factory routine test would be
beneficial.
High Voltage Conference 2015 – IDC Technologies 8

9. Session 11: Application of Australian Standards to HV Switchgear Routine Testing
Measurement of fluid condition after filling on site (AS 62271.200
subclause 7.106)
For fluid-filled compartments, the condition (pressure, volume, etc.) of the fluid
is determined in order to verify compliance with the manufacturer's
specification.
Switchgear components not specifically covered by AS
62271.200
AS 62271.200 deals with the switchgear in general but not specifically with
individual components such as the circuit breakers, disconnectors, contactors,
earth switches, current transformers and voltage transformers which are dealt
with in other standards. Routine testing of these major components are taken
care of as follows;
• Circuit Breakers: AS 62271.100 (High-voltage switchgear and
controlgear Part 100: High-voltage alternating current circuit-breakers)
• Disconnectors and Earth Switches: AS 62271.102 (High-voltage
switchgear and controlgear Part 102: Alternating current disconnectors
and earthing switches)
• Contactors: AS 60470 (High-voltage alternating current contactors and
contactor-based motor starters)
• Current Transformers: AS 60044.1 (Instrument transformers Part 1:
Current transformers)
• Voltage Transformers: AS 60044.2 (Instrument transformers Part 1:
Inductive voltage transformers)
• Protection Relays: The following constitute a good reference for
protection relay routine testing:
o System functional design specification
o IEC 60255 series Standards
High Voltage Conference 2015 – IDC Technologies 9

10. Session 11: Application of Australian Standards to HV Switchgear Routine Testing
Summary
Though Standards on their own have no legal status and no requirement for
compliance, they become mandatory when called up in government legislation
and as a result can be subject to the scrutiny of the courts.
The relevant Australian Standards and other documents for routine testing of
HV switchgear and its major components are summarised in Figure 4.
Figure 4: Relevant Standards and Documents for HV Switchgear Routine Tests
High Voltage Conference 2015 – IDC Technologies 10
Switchgear:
AS 2067
AS 62271.200
AS 62271.1
Protection Relay:
System functional design
specification
IEC 60255 series
Standards
Circuit Breaker:
AS 62271.100
Earth Switch:
AS 62271.102 (also for
Disconnector)
Current Transformer:
AS 60044.1
Voltage Transformer:
AS 60044.2
Contactor:
AS 60470

11. Session 11: Application of Australian Standards to HV Switchgear Routine Testing
References
AS 2067-2014 - Substations and High Voltage Installations Exceeding 1 kV ac.
AS 62271.200 - High-voltage switchgear and controlgear Part 200: A.C. metal-
enclosed switchgear and controlgear for rated voltages above 1 kV and up to
and including 52 kV.
AS 62271.1 - High-voltage switchgear and controlgear Part 1: Common
specifications.
AS 62271.100 - High-voltage switchgear and controlgear Part 100: High-
voltage alternating current circuit-breakers.
AS 62271.102 - High-voltage switchgear and controlgear Part 102: Alternating
current disconnectors and earthing switches.
AS 60470 - High-voltage alternating current contactors and contactor-based
motor starters
AS 60044.1 - Instrument transformers Part 1: Current transformers.
AS 60044.2 - Instrument transformers Part 1: Inductive voltage transformers.
AREVA PIX 12–17–24 kV Air-insulated switchgear Installation, Operation &
Maintenance Manual No. AMTNoT 060-02, Edition 03/2009.
High Voltage Conference 2015 – IDC Technologies 11