Electrical Test Equipment

Question 1

instruments used to measure current
in electrical circuits. Available in clamp-on and halo
styles.

Answer 1

Ammeters

Question 2

instruments
used to locate faults on primary underground cable and are
composed of a time domain reflectometer (TDR) and a surge
generator.

Answer 2

Arc Reflection Systems

Question 3

instruments used to trace the
route of underground cables. They are commonly used as the first
step in fault locating, and consist of a transmitter and hand-held
receiver.

Answer 3

Cable Locator

Question 4

refers to the two most common methods of connecting a cable
locator. The conductive method is where the transmitter is
connected directly to the conductor. The inductive method is where
the transmitter is placed over the cable route.

Answer 4

Conductive/Inductive Tracing

Question 5

a device that attaches
directly to the meter end of a phasing tester and is used to test
cables for faults. This instrument does not locate a fault, it simply
indicates the integrity of a run of cable.

Answer 5

DC Hi-Pot Tester

Question 6

an electrical
device used in conjunction with the surge generator to determine
the exact location of a primary underground cable fault.

Answer 6

Digiphone Pinpointer

Question 7

used to read voltage
and test continuity on low-voltage circuits and equipment. There
are many different types with varying functions.

Answer 7

Digital Multimeter

Question 8

used primarily in substations on subtransmission and
transmission equipment. This instrument is used to detect a
breakdown in insulation, which can impact the power factor of a
circuit.

Answer 8

Insulation Power Factor Tester

Question 9

Also referred to as a “Megger,” a device used to test the insulation in electrical apparatus,
cables, wire, or networks.

Answer 9

Insulation Tester

Question 10

instruments that are used to
check the condition of each insulator of a string. These meters can
be used while the line is energized.

Answer 10

Insulator Tester

Question 11

an instrument used
to measure very low levels of resistance. Its most important
application is to test the resistance of contacts in substation
switches and circuit breakers.

Answer 11

Micro-Ohmeter

Question 12

instruments used to determine the
insulating strength of insulating oils used in transformers, circuit
breakers, and other electrical apparatus

Answer 12

Oil Tester

Question 13

Also known as the rotation meter,
is a low-voltage instrument used
as a reference tool. It ensures that the phase sequence is not
accidentally changed due to maintenance work performed on a
transformer bank or three-phase pad-mount transformer.

Answer 13

Phase Sequence Indicator

Question 14

a high-voltage instrument
used to read voltage and prove phase sequence. Proving phase
sequence is necessary when work is performed on a junction of the
main line feeder circuit in both overhead and underground.

Answer 14

Phasing Meter

Question 15

These instruments are used when a
problem exists on a secondary circuit or service. The problem may
occur at random times and is undetectable during a single visit by a
utility technician. These instruments can be attached and left at the
location for a given period of time.

Answer 15

Recording Volt/Ammeter

Question 16

a specialized device used to confirm when a regulator is in the
neutral position.

Answer 16

Regulator Neutral Detector

Question 17

used on
underground secondary and service cables to determine the exact
location of a fault.

Answer 17

Secondary Fault Locator

Question 18

troubleshooting devices used to apply load to service conductors
while the customer’s main is opened. This allows a determination
to be made as to whether the problem exists on the utility or
customer side of the meter.

Answer 18

Service Conductor Tester

Question 19

Also referred to as a thumper, is used to apply a current to a faulted cable. With the aid of a
listening device such as the digiphone pinpointer, a lineworker can
listen for the electrical discharge at the fault location. This allows for
accurate and precise fault location.

Answer 19

surge generator

Question 20

used to determine the distance from the
connection point to the fault on underground cable. This device has
a scope that displays a wave that shows small waves and dips that
indicate the location of splices, transformers, and faults.

Answer 20

Time Domain Reflectometer (TDR)

Question 21

used to verify the turns ratio between the primary and secondary
coils of a transformer.

Answer 21

Transformer Turns Ratio Tester

Question 22

used to check for the
presence of voltage on an electrical circuit. These devices are most
commonly used prior to installing personal protective grounds.

Answer 22

Voltage Detector

Question 23

most commonly used on primary lines and equipment energized
between 2kV and 34.5kV. Reading and understanding your
company’s policies and the manufacturer’s recommendations
are critical before using any of these instruments. Always wear
approved personal protective equipment when using these
instruments.

Answer 23

High-voltage Test Equipment

Question 24

most commonly used on secondary lines and equipment energized
between 0 and 600 volts. Customer contact is common when
working with these instruments, because the circuits being tested
are often connected to customer property.

Answer 24

Low-voltage Test Equipment

Question 25

Explain Phase Sequence

Answer 25

Phase sequence refers to the order the three phase conductors are connected to lines or equipment. It is important to maintain phase sequence when performing maintenance work on the phase conductors. Phasing sets are used on primary lines, and phase sequence indicators are used on secondary lines to help ensure that phase sequence is maintained.

Question 26

Explain the Phasing Procedure

Answer 26

Phasing a primary feeder consists of the following steps: 1. Proof test the meter 2. Adjust the meter to the proper setting 3. Verify the correct voltage on both sides of the open point 4. Confirm phase sequence

Question 27

Explain Primary Fault Locating

Answer 27

Primary fault locating is most commonly performed with arc-reflection systems. These systems consist of a TDR and surge generator. The TDR determines the approximate distance to the fault and the surge generator, used with a sensitive listening device, helps determine the exact location of the fault.

Question 28

Explain Secondary Fault Locating

Answer 28

Secondary fault locating is usually performed on direct buried cable. The route of the cable is first determined using a cable locator. A transmitter is then attached to the cable which emits a signal at the point of the fault that is detected by a receiver. This manual depicted an “A” frame style receiver on page 44, however, there are other types available.

Question 29

Explain Substation Test Equipment

Answer 29

Many different instruments are used in substations. Substation test equipment is complex and requires a greater level of understanding and training than required for many of the instruments used on low-voltage and high-voltage lines.