Current transformer test set

The test set is designed to perform investigation or testing (calibration) of current measuring converters with a current of up to 300 kA.

Output current range is from 3kA to 300kA.


The test set generates damping sine current waveforms in the measurement loop (included in the scope of supply) with a first half-wave of 10±1 ms duration at a 50±5 Hz signal frequency. The amplitude of the first half-wave of the current can be adjusted in the range of 3 to 300 kA


The test set is recommended by the standard approved by PJSC Rosseti (STO 34.01-3.2-017-2022. Digital current transformers 6-750 kV) for analyzing the accuracy specifications of CTs of unified accuracy classes PR, TPX, TPY and TPZ used for protection, metering and measurements. The test set can be applied for:
  1. Analyzing the behavior of CTs used in relay protection systems under short-circuit conditions and in a transient short-circuit state accompanied by saturation of the magnetic core.
  2. Accuracy testing of protective current transformers for compliance with accuracy classes PR, TPX, TPY, TPZ according to IEC 61869-2-2015.
  3. Calibration of low-power instrument transformers (LPIT), including optical CTs with digital output.

The test set can be used by the laboratories of National Metrology Institutes, manufacturers of instrument and protective current transformers, power industry enterprises and by the territorial bodies of the Federal Agency for Technical Regulation and Metrology (Rosstandart).

General specifications



Amplitude range of the output current for “MarsTest-CT-300“

3-300 kA

Nominal primary current of the current sensor

10/25/250 kA

The maximum charging voltage of the capacitor bank

2,0 kV

The duration of the first half-wave of the current

(10±1) ms

The peak amplitude of the first half-wave of the current

300 kA

Standard deviation of the output current from its setpoint value

±10 %, or less

Charging time of the capacitor bank/p>

1 min, or less

Recommended interval between discharges

3 min, or more

Power supply voltage

(230±23%) V

Power supply frequency

(50 ± 1%) Hz

Power consumption

2 000 VA, or less

Average lifespan

10 years


Power control unit BUS

(635х560х740) mm

Scaling converter PTM-300kA

(810х510х430) mm

Dimensions of the busbar type current transformer under test:

Outside diameter

575 mm

Inside diameter

225 mm


275 mm


Power control unit BUS

150 kg, or less

Scaling converter PTM-300kA

80 kg, or less

Set of cables

3 kg, or less


Key benefits

CTs are tested under conditions that are the closest to the real practice, whereas the test set is powered from the mains supply.

A unified design provides fast and easy connection of the tested transformer irrespective of its size and type.

A special service mode is provided to perform demagnetization of testes CTs with a continuous AC current of up to 8 kA.

Supply package

Power control unit BUS with high-voltage capacitors
Scaling converter PTM-300kA with a busbar type CT installed
User Manual – 1 pcs
USB flash drive with MarsTest-CT software
Transport trolley (2 units)
Transport packaging
ME FLEX 3003-Q
Flexible current sensors for current measurements up to 300, 3000 A
AC Current clamps
Scaling current-to-voltage converters for current measurements up to 100 and 1000A
Multifunctional Reference Instrument Energomonitor 3.3T1
Multifunctional Reference Instrument Energomonitor 3.1KM
Emergency shutdown block
4RS232-USB interface converter
Cable RS-232


User Manual (1.22 Mb, pdf)