Download Chapter-18 Testing Sets for Testing of Energy Meters

Chapter-18
Testing Sets Used For Testing of Energy Meters.
One classification of the testing sets is on the basis of type / make, which is given as
under:
a- Electro-Mechanical / Rotary Electrical Energy Meters Test Sets.
b- Solid State /Electronic/ Computerized Electrical Energy Meters Test Sets.
Another classification is based on the type of testing ( i.e. on-load or off-load) it can
offer, and is appended as below:
-
ON-LOAD Testing:
* Zera.
* Omicron.
-
OFF-LOAD / PHANTOM-LOAD Testing.
* ZFB.
* L & G Type 4.3.( Electro-Mechanical / Rotary Electrical Energy
Meters Test Set.
* Cal port + Cal source (Microprocessor Based).
* Cal mate (Microprocessor Based).
* MTE Type PTS 3.3 C ( Portable Test System, Microprocessor
Based).
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Some of the features of few testing sets are appended as follows:
A-
L & G Type 4.3.( Electro-Mechanical / Rotary) Electrical Energy
Meters Test Set.
This testing set is electromechanical / Rotary type. L & G stands for Landies and
Gyre manufacturer. It is only meant for off load testing (Phantom load testing). Phantom
means fictitious load. It consists of three units as given below. These units must be
interconnected properly through appropriate cables supplied with the testing set.
1. Power Supply unit.
2. Load and Power Factor unit.
3. Digital reference standard energy meter (Accuracy Class 0.05) with comparator.
4. Additional gadgetry called as scanning head (Digital or electromechanical ) is
also needed to get feed back from the Target (Under Test) Energy Meter
1.
Power Supply unit.
The input required to power supply unit is Three-Phase, Four wire, 440 volts
A.C, and is Phase sensitive. i.e. if phase sequence of input supply is wrong, test set
indicates this by turning power supply light into Red colour; other wise Green light
indicates proper phase sequence.
Power supply Unit produce Low voltages proportionate to CT and PT
voltages for Load and Power Factor unit.
This unit has different electromechanical knobs for appropriate controls.
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2.
Load and Power Factor unit.
This unit gets its supply from power supply unit and produce appropriate CT current
and P.T voltage, selectable by rotary switches. Phase angle control is also provided by
a rotary knob.
Voltage output (P.T) selection ranges from 57.7 V AC, 3-Φ,4-wire (phase to
neutral) which is equal to 100 V AC, 3-Φ, 4-wire (phase to phase) to 63 V AC, 3-Φ,4wire (phase to neutral) which is equal to 110 V AC, 3-Φ,4-wire (phase to phase), etc.
Current output ( C.T) selection ranger are of two types i.e.
Course current settings: 10 A or 100 A.
Fine current settings
: 0 to maximum for each course setting (10 A or 100A)
Phase Angle / Power Factor Adjustment: This is provided from 0o to 90o
lagging or leeding ( corresponding to P.F 1 to 0 respectively) with a fine setting
rotary knob.
3. Digital reference standard energy meter (Accuracy Class 0.05) with
comparator.
This unit is reference standard energy meter ( Accuracy class 0.05) also having a
key pad for different selections, which includes:
-
Power or energy measurements.
-
Error measurements.
-
Star / Delta connection.
-
Meter (under test) constant data entry key.
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4. Additional gadgetry called as scanning head (Digital or electromechanical )
The scanning head is not a part of test set, though it is needed additionally to
complete the test setup. Digital scanner is employed for digital energy meter (under test /
target) and electromechanical scanner for electromechanical energy meter (under test / target)
It is needed to get feed back from the Target (Under Test) Energy Meter i.e reads the
revolutions or impulses, for comparison purpose.
B-
Cal port + Cal source (Microprocessor Based).
This testing set comprises of two units called as source unit and the port unit.
This testing set offer both types of testing of energy meter i.e. “ON-LOAD test” and “OFFLOAD test”.
The test units have LCD display, numeric and function key pads for receiving data
like meter data, transformer data, admin data, consumer data etc.
Source unit takes single phase 220V AV supply as input and produce proportionate
low voltages for V.T and C.T respectively.
The output of the source unit is then feed to port unit, which offers different options
for testing like star / delta connection, energy or power measurements / error measurements,
in-feed voltage and current selection for target energy meter etc.
The scanning head used with this test set is hybrid scanner i.e. have a switch selection
for digital or electromechanical versions of the (Target)energy meter.
In collaboration with a computer and this test set, automatic testing can be performed.
For storage and display of data (hard copy) printer can be attached with the testing set
computer.
Other feature like harmonic analysis and wave form analysis make this set better than
L&G type described earlier.
C-
Cal mate (Microprocessor Based).
This testing set comprises of one unit called as calmate based on microprocessor, and
comprises of both units (source and the port unit), contained in a single unit, which makes
this test set more compactable.
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This testing set offer both types of testing of energy meter i.e. “ON-LOAD test” and
“OFF-LOAD test”.
The test units have LCD display, numeric and function key pads for receiving data
like meter data, transformer data, admin data, consumer data etc.
Calmate takes single phase 220V AV supply as input and produce proportionate low
voltages for V.T and C.T respectively.
The Calmate offers different options for testing like star / delta connection, energy or
power measurements / error measurements, in-feed voltage and current selection for target
energy meter etc.
The scanning head used with this test set is hybrid scanner i.e. have a switch selection
for digital or electromechanical versions of the (Target) energy meter.
In collaboration with a computer and this test set, automatic testing can be performed.
For storage and display of data (hard copy) printer can be attached with the testing set
computer.
Other feature like harmonic analysis and wave form analysis make this set better than
Cal port + Cal source type described earlier.
D-
MTE Type PTS 3.3 C ( Portable Test System, Microprocessor
Based).
This testing set is a single unit based on microprocessor, includes a reference standard
energy meter of accuracy class 0.05. Both on-load and off-load testing features are offered by
this testing set. It also includes clamp-on C.T for on load testing (with out disturbing the
metering system).
Despite energy measurement or error measurement automatically, it can display
vector diagram, wave form. Harmonic analysis and register test feature are also available.
Transformer test includes Burden measurement of voltage transformer and current
transformer each.
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General
The “PTS 3.3 C” portable test system consists of an integrated three phase current
and voltage source and a three phase electronic reference standard of accuracy class 0.05 %.
Characteristic features of PTS 3.3 C are its wide measuring range, high accuracy, and
high tolerance to unwanted external influences.
The PTS 3.3 C allows the monitoring of meter installation as well as analysis of the
local mains conditions.
Advantages

Easy verification of meters under precise load conditions, using the
built-in, compact current and voltage source.

Automatic operation with predefined load points without the need for
an external PC.

Exchangeable compact flash (CF) memory card for measurement
results and customer data.

Display of vector diagram and phase sequence for analysis of the
supply conditions

User-friendly system for data input and operation of combined source
and reference meter.

The system may be used either as a stand-alone reference standard
meter, or together with the integrated power source.
Functions

Independent generation of single or three phase loading conditions for
verification of meters.
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
Active, reactive and apparent energy measurement for three-phase, 3
or 4 wire, system with integrated error calculator and pulse output.

Vector diagram, harmonic spectrum, wave-form and rotary field
display for analysis of the mains conditions.

Burden measurement of Current Transformer (CT) and Potential
Transformer (PT).
Applications

On site meter measurement testing

Verification of energy registration.

Verification of the circuit load conditions.
Options

Software CALSOFT.

Error compensated clip-on CT’s up to 100 A.
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