SIST IEC 60145:1995

Var-hour (reactive energy) meters

Applicable to newly manufactured induction type var-hour meters for the measurement of reactive energy of frequency between 40 Hz and 60 Hz, of an accuracy class of 3.0 for ordinary usage, and to their type tests.

Compteurs d'énergie réactive (varheuremètres)

Applicable aux varheuremètres à induction neufs, d'usage courant, de classe de précision 3,0. de fréquences comprises entre 40 Hz et 60 Hz, et à leurs essais de type.

Števci jalove energije

General Information

• Status: Published
• Publication Date: 31-Jul-1995
• ICS: 17.220.20 - Measurement of electrical and magnetic quantities
• ICS: 29.260.20 - Electrical apparatus for explosive atmospheres
• ICS: 91.140.50 - Electricity supply systems
• Technical Committee: MEE - Equipment for electrical energy measurement and load control
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Aug-1995
• Due Date: 01-Aug-1995
• Completion Date: 01-Aug-1995
• Ref Project: IEC TR 60079-15:1987 - Electrical apparatus for explosive gas atmospheres. Part 15: Electrical apparatus with type of protection 'n'

Overview

SIST IEC 60145:1995 specifies the requirements for induction type var-hour meters designed to measure reactive energy in the frequency range of 40 Hz to 60 Hz. This standard is applicable to newly manufactured meters with an accuracy class of 3.0 intended for ordinary usage, and provides detailed guidance on their type tests, mechanical and electrical requirements, classification, markings, and accuracy verification. The standard ensures uniformity and reliability in the measurement of reactive energy, supporting accurate monitoring and billing in electricity supply systems.

Key Topics

• Scope

  • Applies to induction type var-hour (reactive energy) meters for new installations.
  • Frequency range covered: 40 Hz to 60 Hz.
  • Accuracy class addressed: 3.0, suitable for general use.

• Definitions

  • Clarifies essential meter components such as meter rotor, register (counting mechanism), terminal block, and circuits (current, voltage, auxiliary).
  • Describes major measurement terminologies: reference voltage, rated maximum current, reference frequency, error definitions, and meter constant.

• Classification

  • Meters categorized by accuracy class and degree of phase displacement (0, 60, or 90 degrees).

• Mechanical Requirements

  • Specification for non-hygroscopic materials and protection against corrosion.
  • Dustproof casing with secure sealing.
  • Grouped, robust terminal blocks and appropriately designed registers and covers.

• Electrical Requirements

  • Standard basic currents and reference voltages defined.
  • Power losses limited for both voltage and current circuits.
  • Dielectric strength and insulation requirements.
  • Limits on permissible temperature rise during operation.

• Markings and Nameplates

  • Mandatory manufacturer and meter information, including serial number, type, rated values (voltage, current, frequency), and meter constant.
  • Clear designation of the intended circuit type and essential technical specifications.

• Accuracy and Testing

  • Error limits and performance criteria under normal and varied conditions (temperature, voltage, frequency, and external magnetic fields).
  • Requirements for starting, running with no load, and endurance under fault conditions (short circuit tests).
  • Detailed method for type, routine, and sampling tests.

Applications

The use of var-hour (reactive energy) meters as per SIST IEC 60145:1995 is vital in:

• Electricity Supply Systems:
  Accurate measurement of reactive power in residential, commercial, or industrial installations to ensure correct billing and efficient grid management.
• Utility Metering:
  Var-hour meters are a standard tool for utilities to monitor and manage reactive energy consumption, which affects overall grid stability and power factor correction initiatives.
• Compliance and Procurement:
  Manufacturers, utilities, and procurement entities refer to this standard to ensure consistency in product quality, testing processes, and regulatory compliance for newly installed meters.

Related Standards

To provide a comprehensive approach to metering and energy measurement, consider these related standards:

• IEC 62053 series: Standards for various accuracy classes and technologies of electricity meters.
• IEC 62054: Specifications for meter test equipment, installation, and maintenance.
• IEC 60044: Instrument transformers, often used with var-hour meters.
• IEC 62056: Data exchange for meter reading and control.
• SIST EN 50470: European standard for electricity metering devices.

Keeping var-hour meters compliant with SIST IEC 60145:1995 ensures reliable, consistent, and accurate measurement of reactive energy, supporting efficiency and transparency in modern electricity distribution networks.

Standards Content (Sample)

SLOVENSKI STANDARD
01-avgust-1995
Števci jalove energije
Var-hour (reactive energy) meters
Compteurs d'énergie réactive (varheuremètres)
Ta slovenski standard je istoveten z: IEC 60145
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
91.140.50 Sistemi za oskrbo z elektriko Electricity supply systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

NORME CEI
INTERNATIONALE IEC
INTERNATIONAL
Première édition
STANDARD
First edition
Compteurs d'énergie réactive (varheuremètres)
Var-hour (reactive energy) meters
de reproduction réservés — Copyright — all rights reserved
© CEI 1963 Droits
No pa of this publication may be reproduced or utilized in
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CONTENTS
Page
FOREWORD
PREFACE 5
Clause
1. Scope 7
2. Units 7
Definitions 7
3.
13 4. Classification
5. Mechanical requirements
6. Electrical requirements
Markings of meters — Nameplates 7.
8. Accuracy
Connection diagrams and terminal markings 9.
Graphical symbols for var-hour meters APPENDIX —

— 5 —
INTERNATIONAL ELECTROTECHNICAL COMMISSION
VAR-HOUR (REACTIVE ENERGY) METERS
FOREWORD
1) The formal decisions or agreements of the I.E.C. on technical matters, prepared by Technical Committees on which
all the National Committees having a special interest therein are represented, express, as nearly as possible, an inter-
national consensus of opinion on the subjects dealt with.
2) They have the form of recommendations for international use and they are accepted by the National Committees in
that sense.
3) In order to promote this international unification, the I.E.C. expresses the wish that all National Committees having
as yet no national rules, when preparing such rules, should use the I.E.C. recommendations as the fundamental basis
for these rules in so far as national conditions will permit.
4) The desirability is recognized of extending international agreement on these matters through an endeavour to harmonize
national standardization rules with these recommendations in so far as national conditions will permit. The National
Committees pledge their influence toward that end.
PREFACE
These Recommendations were prepared by Sub-Committee 13A, Integrating meters, of Technical
Committee No. 13, Measuring instruments.
Drafts were discussed at meetings held in Stockholm in 1958 and in Paris in 1960. The final draft
was submitted to the National Committees for approval under the Six Months' Rule in April 1961.
The following countries voted explicitly in favour of publication :
Austria
Netherlands
Belgium
Norway
Czechoslovakia
Romania
Denmark Sweden
Finland Switzerland
France
Turkey
Germany
Union of Soviet Socialist Republics
Hungary
United Kingdom
Italy Yugoslavia
Japan
VAR-HOUR (REACTIVE ENERGY) METERS
1. SCOPE
The present recommendations apply only to newly manufactured induction type var-hour meters
for the measurement of reactive energy of frequency between 40 and 60 Hz (c/s), of an accuracy
class of 3.0 for ordinary usage and to their type tests.
They do not apply to special types of var-hour meters except multi-rate meters.
They do not apply to instrument transformers, even when used in conjunction with the meters
covered by these recommendations.
2. UNITS
The units employed in these recommendations are those adopted by the International Electro-
technical Commission.
DEFINITIONS
3.
Some of the following terms have been taken from those given in the International Electrotechnical
20 (Publication 50 (20) (1958). In such cases the appropriate I.E.V. reference is
Vocabulary, Group
given. Some other terms or their definitions have been added especially for these recommendations.
(reactive energy meter)
3.1 Var-hour meter
An integrating instrument which measures reactive energy * in var-hours or in suitable multiples
thereof.
3.2 Induction meter
A meter in which fixed coils carrying current act upon a conducting moving element, generally
a disk, in which flow currents induced by the coils (I.E.V. 20-25-065).
is not available in the I.E.V., and general definitions for reactive power and energy do not
* The term reactive energy
exist for cases where the alternating quantities are not sinusoidal.
For these reasons the present recommendations are based on the following practical definitions, which are strictly
correct only for sinusoidal voltages, but which are for practical purposes true where the voltages and currents are nearly
sinusoidal.
Reactive energy in a single-phase circuit
Quantity measured by a perfect watt-hour meter which carries the current of a single-phase circuit and a voltage equal
in magnitude to the voltage across the single-phase circuit but in quadrature therewith. The reactive energy of an inductive
circuit is positive.
Reactive energy in a polyphase circuit
The algebraic sum of the reactive energies of the phases.
Because these practical definitions of reactive energy assume sinusoidal quantities, the inductive or capacitive state
of a circuit in these recommendations is given by the factor " sin ".
y
— 9 —
3.3 Multi-rate meter
A meter provided with a number of registers each becoming operative at times corresponding
to differing rates of charge (I.E.V. 20-25-110).
3.4 Meter rotor
The moving part of a meter upon which the fixed windings react.
Driving element of an induction meter
3.5
One of the working parts of the meter which produces a torque by its action on the moving element.
It generally comprises an electro-magnet with its control devices (I.E.V. 20-35-185).
Meter braking element
3.6
That part of a meter which is intended to produce a braking torque by its action on the moving
element. It comprises one or more magnets and their setting device (I.E.V. 20-35-190).
Register of a meter (counting mechanism)
3.7
That part of a meter which registers the energy, or more generally the value of the quantity measured
by the meter (I.E.V. 20-35-180).
3.8 Meter base
The back of the meter by which it is fixed and to which are attached the frame, the terminal block
and the cover (I.E.V. 20-35-160).
3.9 Meter cover
The enclosure on the front of the meter, made sometimes of transparent material, but generally
including transparent parts through which the movement of the disk can be seen, and the counting
mechanism read (I.E.V. 20-35-170).
3.10 Meter case
This comprises the base and the cover (I.E.V. 20-35-175).
Meter frame
3,11
That part to which are affixed the driving element, the counting mechanism, usually the braking
element, and sometimes the adjusting devices (I.E.V. 20-35-165).
3.12 Terminal block
A support made of insulating material on which all terminals of an instrument, or part of them,
are grouped together (I.E.V. 20-35-135).
Terminal cover
3.13
Auxiliary cover which covers the meter terminals and the ends of the wires or the cables from the
apparatus connected to these terminals (I.E.V. 20-35-195 modified).
3.14 Current circuit
That part of a meter through which flows the current in the circuit which it measures, or a pro-
portional current supplied by a current transformer (I.E.V. 20-35-205 modified).

— 11 —
3.15 Voltage circuit
That part of a meter supplied by the voltage of the circuit it is to measure or by a proportional
voltage supplied by a transformer or voltage divider (I.E.V. 20-35-210 modified).
3.16 Auxiliary circuit(s)
Circuit(s) within the meter case and connected to an auxiliary device, for example, an hour meter,
a clock, a trip coil, a relay.
Basic current
3.17
The value of the current which serves as a basis for these recommendations.
Rated maximum current
3.18
The value of current up to which the meter purports to meet the highest accuracy requirements
of these recommendations.
3.19 Reference voltage
The value of voltage which forms the basis of these recommendations, if the meter is marked for
one voltage only.
If the meter is marked for a range of voltages of which the ratio between the upper and lower limits
does not exceed 1.3 *, the reference voltage is the arithmetic mean of the extreme values of the range,
for all tests except those prescribed in Sub-Clauses 8.2.1 and 8.2.5.
If the meter is marked for two voltages of which the ratio between the higher one and lower one
exceeds 1.3, these two voltages are to be considered as reference voltages and all the tests are to be made
for both.
-hour meters for 3-phase circuits, the reference voltage will be the voltage applied to the
In var
voltage circuit(s), which may include external devices.
Reference frequency
3.20
The frequency which forms the basis of these recommendations.
3.21 Reference speed
The number of revolutions per minute of the rotor when the meter carries reference voltage, and
basic current, sin y = 1.
3.22 Reference torque
The torque of the rotor when at rest, when the meter carries reference voltage and basic current,
sin = 1.
*U
upper
1.3
U
lower
— 13 —
3.23 Constant of a var-hour meter
Coefficient giving the relation between the reactive energy nominally measured by a meter and the
corresponding angular movement of the rotor.
It is usually expressed as var-hours per revolution (varh/rev) or in revolutions per kilovar-hour
(rev/kvarh).
Reference temperature
3.24
The ambient temperature for which the meter is intended.
3.25 Type tests
Qualifying tests which are made on a meter, or on a small number of meters of the same type.
3.26
Routine tests
Tests carried out on every meter in a consignment.
3.27
Sampling tests
Tests carried out on a sample of a consignment.
3.28 Errors
a) Absolute error
The indicated value of reactive energy minus its true value . expressed algebraically (I.E.V.
20-40-085 modified).
b) Relative error
The ratio of the absolute error to the true value of the reactive energy (I.E.V. 20-40-090 modified).
c) Percentage error
Relative error x 100.
3.29 Distortion factor
The ratio between the r.m.s. value of the harmonic content obtained by subtracting the funda-
mental wave from a non-sinusoidal periodic quantity and the r.m.s. value of the non-sinusoidal quantity.
It is usually expressed as a percentage.
3.30 Mean temperature coefficient
The ratio between the relative variation of a quantity and the change of temperature which
produces it.
4. CLASSIFICATION
4.1 Var-hour meters may be classified according to :
— Class of accuracy, each class being denoted by a number corresponding to the percentage accuracy
limit at basic current and sin = 1 under the conditions of Sub-Clause 8.2.1.
p
In this edition of the recommendations the meters concerned are classified as 3.0.

— 15 —
— Degree of phase displacement, each class of single driving element * of a var-hour meter which is
characterized by the nominal phase displacement between the voltage and current magnetic
fluxes in the principal air gaps when the voltage and current applied to this single driving
element are in phase.
Var-hour meters which are the subject of these recommendations usually fall into one of three
classes : 0, 90 and 60.
MECHANICAL REQUIREMENTS
5.
5.1 General
All insulating materials used in the construction of meters shall be substantially non-hygroscopic.
All parts which are subject to corrosion under normal working conditions shall be effectively
protected against corrosion due to atmospheric causes. Any protective coating shall not be liable to
damage by ordinary handling nor injuriously affected by exposure to air, under ordinary conditions of
service.
5.2 Case
The meter shall have a reasonably dust-proof case, which can be sealed such that the mechanism
of the meter is only accessible after breaking the seals.
Metal cases of meters for use on a voltage exceeding 250 V to earth shall be provided with means
for the effective connection of an adequate earthing conductor.
5.3
Windows
If the meter case is not transparent, one or more windows shall be provided for reading the register
and the observation of the rotor. These windows shall be covered by plates of transparent material,
which cannot be removed without breaking the seals.
5.4 Terminals — Terminal block
The terminals shall be grouped in a terminal block of adequate mechanical strength. They shall
permit the connection of both solid and stranded conductors. It shall be possible easily to disconnect
the voltage terminals from the current terminals.
The manner of fixing the conductors to the terminals shall ensure adequate and durable contact
such that there is no risk of loosening or undue heating. The holes in the insulating material which form
a prolongation of the terminal holes shall be of sufficient size to accommodate the insulation of the
conductors.
5.5 Terminal cover
The terminals of a meter shall have a separate cover which can be sealed independently of the meter
cover. The terminal cover shall enclose the actual terminals, their fixing screws, and if required a suitable
length of the external conductors, and their insulation.
* Driving element here includes any necessary accessory resistors, inductors and shunts.

— 17 —
When the meter is fixed, no access to the terminals shall be possible without breaking the seals
of the terminal cover.
5.6 Register (counting mechanism)
The register may be of the pointer or of the drum type.
The principal terms in which the register records shall be the kilovar-hour (kvarh) or the megavar-
hour (Mvarh).
In drum type registers, the terms in which the register records shall be marked adjacent to the
assembly of drums.
In pointer type registers, the terms in which the register records shall be marked adjacent to the
1 Mvarh/div ", and adjacent to the other dials shall be marked
units dial in the form " 1 kvarh/div " or "
the number of kilovarhours or megavarhours respectively corresponding to one division of each dial.
For example, in a meter registering in terms of kilovarhours, the units dial shall be marked " kvarh/div "
and adjacent to the other dials to the left of the units dial shall be marked 10 — 100 — 1 000 — etc.
Decimal dials or drums shall be coloured, or encircled in colour, the fastest moving being graduated
and numbered.
The register shall be able to record, starting from zero, for a minimum of 2 500 hours for meters
500 hours for those marked " 1 500 hours ", the reactive
marked " 2 500 hours " and a minimum of 1
= 1.
energy corresponding to rated maximum current at reference voltage and sin
y
Register markings shall be indelible and easily readable.
Meter rotor, direction of rotation
5.7
The edge of the rotor near to an observer viewing a meter from the front shall move from left
to right on inductive or capacitive load, according to the intended use of the meter. The direction of
rotation shall be marked by a clearly visible, indelible arrow.
a visible mark to facilitate revolution counting.
The edge and upper surface of the disk shall car ry
Other marks may be added for stroboscopic or other tests, but such marks shall be so placed as not to
interfere with the use of the main visible mark for photo-electric revolution-counting.
5.8 Iron cores
The iron cores of current and voltage windings shall not be relied upon for stiffening the frame
structure.
6. ELECTRICAL REQUIREMENTS
6.1 Standard basic currents
Standard basic currents are :
1-2-5— 10-20-30-50 and 100 A.
— 19 —
Standard reference voltages
6.2
Standard reference voltages are :
57.7-63.5-100-110-127-190-220-240-380-420-480-500 and 600 V.
Voltages underlined are identical with those in I.E.C. Publication 38.
Power losses *
6.3
a) Voltage circuit
The loss in each voltage circuit of a meter at reference voltage(s) and reference frequency shall
not exceed 5 W and 10 VA.
Current circuit
b)
The apparent power taken by each current circuit of a current transformer operated meter at
basic current shall not exceed 5 VA.
6.4 Dielectric strength
Var-hour meters and their accessories, except instrument transformers, which are covered else-
where, must be such that they lose none of their dielectric qualities when subjected to normal se rvice
voltages.
A meter or accessory is considered to satisfy the foregoing condition if it withstands satisfactorily
the dielectric proving test stated hereafter.
Further, the insulating materials employed must be such that they lose none of their dielectric
qualities under the influence of atmospheric humidity. All hygroscopic and combustible material used
as insulation must be treated to avoid the penetration of moisture.
The dielectric test shall only be applied to complete meters and not to unassembled components,
and shall only be applied once to any meter.
The insulation between all circuits of a meter (including any metal parts in contact therewith)
other than circuits of auxiliary devices operating at voltages below 70 V and the frame of the meter shall
withstand the application of an alternating test voltage of 2 000 V r.m.s. The circuits of auxiliary
devices operating at voltages below 70 V shall be connected to the frame of the meter during this test.
During the above test all exposed metal parts shall be connected to the frame of the meter. If the
meter has a moulded insulation base then, during the above test, it shall be laid on its back on a flat metal
surface which shall also be connected to the frame of the meter.
The insulation between two circuits which include windings on the same iron core, and between
which line-to-line voltage appears when the meter is in service, shall withstand the application of an
alternating test voltage of 2 000 V r.m.s.
The insulation between each circuit of the meter including metal parts in contact therewith and
each and every other circuit which can be separated therefrom other than circuits of auxiliary devices
* These losses refer to those parts of the voltage and current circuits within the meter case.

— 21 —
operating at voltages below 70 V shall withstand the application of an alternating test voltage of twice
the line-to-line reference voltage with a minimum of 600 V. During this test the circuits of auxiliary
devices operating at less than 70 V shall be connected to the frame of the meter.
The insulation between the frame of the meter and auxiliary circuits operating at voltages below
70 V shall withstand the application of an alternating test voltage of 250 V r.m.s.
The test voltage shall be substantially sinusoidal, and of frequency between 40 and 60 Hz (c/s).
It shall derive from a source of not less than 500 VA and it shall be applied for one minute.
...