Three Phase Portable Reference Standard

Model LH

The three phase reference standard meter (TPRS-1107) from SANDS is portable equipment. The main objective of this device is to calibrate the errors in three-phase and single-phase energy meters i.e. the meter under test (MUT). The TPRS supports both static and electro-mechanical types of meters. It can also be used to compute the voltage, current, energy, power factor etc of the meter under test. It has an LCD display, an alphanumeric keypad that makes it easy for the user to operate the TPRS. It can be interfaced with the PC for data analysis. It has a capability of storing up to 8000 test results.


  • Storage of 8000 test results with search facility
  • Primary calibration LED (kWh and KVArh)
  • Graphical Display 240 x 128 with backlit
  • Membrane keypad with separate keys for alphabetsand Numbers”
  • Sofware diagnostic feature
  • Data transfer through RS-232 serial port
  • External portable printer for on-site printing (optional)
  • Current transformer ratio checking
  • Simultaneous test for CT operator meters in primary and secondry side of CT


  • High current range clamp on CT with cable
  • Low current range clamp on CT with cable
  • Cable for ring CT
  • Cable for field & laboratory use
  • Scanner with stand
  • Snap switch for Manual Operation
  • Communication cable for downloading
  • Base computer software
  • Portable Printer Optional
  • Optical probe for DLMS Dial test


  • Elimination of human error
  • Confident test results
  • Portable, compact & easy to use
  • Interface to an External printer (optional)
  • Voltage clip – type Connectors for safety
  • Testing without service interruptions
  • No external projections, by which the epuipment could be damanged
  • DLMS meter also calibrate throught optical probe
  • 8000 Records storage
  • Complete calibration and testing for CT operator

Working with TPRS

Following steps are involved in performing calibration of meter using TPRS.

  1. Perform power – up operation of the TPRS.
  2. Select the settings menu from the main menu.
  3. In settings select the connection type option and select the appropriate options (for more details refer settings menu).
  4. Then select the Meter calibration option and select the calibration mode (for more details refer settings menu).
  5. Selection of Meter Calibration from Main menu.
  6. Meter Details: Meter detail screen will appear to enter the meter related information like meter serial number, consumer number, consumer ID, meter type, etc. This information is saved along with the record of the meter for future reference.
  7. Entering Calibration parameters: On pressing F3 the calibration parameters screen will appear according to calibration mode selected. Here user should enter the No of pulses, energy type, test time etc. Key F3 should be pressed to proceed to next screen.
  8. Performing actual test. The actual computation of error is done here. The method to compute error will depend upon the calibration parameters and meter calibration mode selection. After computation the error report (record) id stored. User can view it in records menu.

Connection Diagram

Model LH+

Technical Specifications

TPRS-1107-H TPRS-1107-L TPRS-1107-LH TPRS-1107-H+ TPRS-1107-L+ TPRS-1107-LH+
Applications HT Meters LT-CT operated meters HT Meters HT Meters LT-CT operated meters HT Meters
LT-Whole current meters LT-CT operated meters LT-Whole current meters LT-CT operated meters
LT-Whole current meters CT Ratio test for
LT-CT operated meters
LT-Whole current meters
CT Ratio test for
LT-CT operated meters
Direct Mode
Current 10mA-10A 10mA-10A 10mA-10A NA NA NA
Accuracy 0.2S / 0.2 0.2S / 0.2 0.2S / 0.2
Clamp on Mode
/Primary current
Current NA 500mA-100A* 500mA-100A* NA 500mA-100A* 500mA-100A*
Accuracy 0.5S / 0.5 / 0.2S / 0.2 0.5S / 0.5 /0.2S/0.2 0.5S / 0.5 /0.2S 0.5S / 0.5 /0.2S
Current Measurement
Current NA NA NA 50mA-10A 50mA-10A 50mA-10A
Accuracy 0.2S 0.2S 0.2S
Display Resolution & Parameters
• Volage 0.01 V
• Current 0.0001 A
• Power Factor 0.001
• Frequency 0.001 Hz
• Energy 0.00001 Wh
• Error Percentage 0.00%
• To analyse the waveform distortion
• o identify cases of CT saturation
• Available for both Voltage and Current channels
• Voltage and Current Harmonic Distortion
• Analysis upto 21 st Harmonic
Instantaneous Measurement
• Simultaneous display of all Instantaneous parameters
• Phase-wise – Voltage, Current, Active & Reactive Current and power Factor
• Phase wise active,Reactive and Apparent Power
• Average Power Factor and Frequency
• Phase to Phase Voltage and Angle
• Dimension 275 x 210 x 110 mm (not exceeding)
• Enclosure ABS FR (V-O) (High Strength Moulded)
• Operating Temp -10 to 50 Deg C
• Storage Temp -25 to 70 Deg C
• Rel. Humidity 95% non-condensing
• Phasor diagram to visualise the phase sequence and lead / lag conditions
• Identification of CT reversal, Phase Sequence reversal, CT / PT interchange, Low Power factor
• IEC 60687
• IS 14697