Tamper Testing:A complex task made easier by tamper conditions simulator

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Metering community that includes the engineers from electrical utility, manufacturer & test laboratories are working harder and harder to reduce the revenue losses due to tampering in the energy meter by the consumer. Several years of study and experience reveals that there are numerous possibilities to manipulate with meters supply wiring. Tamper protection is highly important issue for utility, meter manufactures & test labs. Various governmental schemes such as APDRP/R-APDRP also emphasizing to have tamper proof meters. It is extremely challenging to remember & simulate all these various combination while testing the tamper proof functionality of single phase energy meter.

This application note explains how the tamper simulator (1phase) has made easier and systematic to test the tamper testing without making any change in the external connection in the meter.

Challenges in Tamper Testing

Test engineer encounter the following difficulties while testing the tamper recording or tamper proof feature in the single phase meters.

  • To remember all the possible wiring combination and permutation to test the tamper recording features
  • The process of simulating tamper conditions is time consuming , laborious and involves lot of manual connection-reconnections, which can result in connection errors, fatigue, danger due to electrical shock, improper, incomplete testing/checking of energy meters.

The Solution:- Tamper simulator

Several years of research & discussion with the metering experts in the field of tamper detection, analysis & diagnoses, meter testing & manufacturing; SNG has developed a tamper simulator based on microprocessor control circuits.

The simulator is capable of creating 38 different types of tamper conditions by just selecting the predefined tamper condition (see Annex 1 for all tamper test conditions) using the feather touch key pad. The selected tamper condition will be displayed on the LCD display. Operator need not to change any physical connection or to do re-wiring to create a tamper condition. Meter connection terminal is provided for easy and quick connection through spring loaded quick connectors.

The digital panel meters are provided to indicate the voltage, current & current during partial load.

A programmable timer is provided to programme the ON time, OFF time and number of cycle for which test has to be carried out as per tamper condition

The tamper simulator save the great amount of time and provides chances to diagnose the meter functionality thoroughly without fatigue to tester.


The tamper simulator has following features:-

  • Microprocessor based controller unit with keypad & LCD display to select and indicate the different tamper conditions (up to 38).
  • Digital Indication devices
    • Voltmeter to indicate the output voltage
    • Ammeters to indicate the main & Partial load current
    • Programmable Timer for ON-OFF control and number of cycle as per the tamper condition
  • Separate terminals are provided for connecting
    • Main & Partial load
    • Resistance & Capacitance
    • Reference standard for accuracy test
  • Meter connection by spring loaded quick connectors.
  • It is possible to provide scanner, error calculation and indication system to perform the accuracy test using scanning head. User can use any make of reference standard (Optional feature)
  • Possible to vary the firing angle in AC chopped signal

The below mentioned tamper conditions are the primary group of various simulated tampers condition (38):

  • Phase – Neutral connection
  • Current reversal
  • Different earth Fault
  • Injection of DC signals
  • Current Bypass
  • Neutral Removal
  • Injection of AC chopped Signals
  • Earthing using Resistive and capacitive load


The tamper simulator save the great amount of time and provides chances to diagnose the meter functionality thoroughly without fatigue to tester. The tamper simulator is designed to provide following benefits to test engineers such as

  • No laborious manual work to wire-rewire the meter under test.
  • No need to remember all tamper condition and corresponding wiring
  • Safe, easy & quick testing
  • Quick connections
  • Provision to connect the reference standard gives the chance to diagnose it more thoroughly and understanding

Technical Specifications

Input Supply Voltage 1ph 240 V, 50Hz (protected by fuse & MCB)
Output supply voltage Same as input
Output current Output Current Full load – 5 Amp @240V

Partial load – 2.5 Amp @240 V

Output loading Resistive load for full and partial loading
Display /Indications v  LCD display to indicate selected different tampers

v  Mains ON indication lamp

v  Voltmeter for output voltage

v  Ammeter for full load current

v  Ammeter for partial load current

Controls v  Mains ON/OFF switch

v  User friendly feather touch keypads to select different tamper conditions

v  Potentiometer to vary the firing angle in AC chopped signal

Connections Spring loaded quick acting device for MUT

Separate terminal for standard meter

Measurement of errors


System to measure error under different tamper conditions

v  Display and measurement unit

v  Scanning head to pick the pulse

Annex 1:- Tamper Conditions simulated by Tamper simulator Nomenclature

1S = Phase voltage (wire) at Supply side of meter 2S = Neutral voltage (wire) at supply side of meter
1L = Phase voltage (wire) at Load side of meter 2L = Neutral voltage (wire) at load side of meter



The conditions explained in this application note are with the objective to assist the test engineers to fight against the energy tampering where ever it is taking place. We request the readers of this application note to use the document carefully and ensure that it does not land up in the wrong hands.

In any case, SNG is not responsible and does not take any liability, in any form on spreading the content of the application with wrong intentions or for wrong purposes and subsequent losses or damage occurred due to it.

Our contact details

RPP Engineering & Consulting GmbH

Winzer Str 20, 53639 Königswinter Germany

Tel no +49 2223 906647

Email yknama@rpp-ec.com

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