The instrument transformer can reduce AC voltage or high current levels to where AC voltage or high current can be directly measured by the instrument. Instrument transformers are composed of current transformer (CT) and potential transformer (PT) and LCOE is specialized in verifying both dielectric and metrological capabilities in a wide range of products.

Tests & Reference Standards

• Complete type tests, tests for accuracy, routine tests and special tests on medium voltage and high voltage instrument transformers according to IEC 61869 series and IEEE C57.13 Standards.
• Capacitive voltage transformers according to IEC 61869-5 and ANSI C93.1.
• Combined transformers according to IEC 61869-4 Standard. Temperature-rise tests applying voltage and current at the same time and mutual influence tests.
• Low power instrument transformers according to IEC 61869-6 Standard, LPCT according to IEC 61869-10 and LPVT according to IEC 61869-11.
• Instrument transformers for DC applications according to IEC 61869-14 and IEC 61869-15.
• HV Capacitors, coupling capacitors, capacitor for PLC application and high voltage dividers according to IEC 60358-1, IEC 60358-2 and ANSI C93.1 Standards.

Capabilities & Products
• Current transformers for metering and protection up to Ipr 8000 A and Um 550 kV
• Inductive voltage transformers for metering and protection up to Um 550 kV
• Capacitive voltage transformers up to Um 420 kV
• Combined transformers up to Um 420 kV and Ipr 4000 A
• High voltage capacitors and voltage dividers up to Um 420 kV


Power transformers are used to receive low voltage generator electric power and transmit it across the power grid network. It forms a crucial part of the power grid and helps in transmission of power from one network to the other without change in frequency.

Tests & Reference Standards
• Routine tests according to IEC 60076-1 and IEEE C57.12.90 Standards. Measurement of voltage ratio, short-circuit impedance, windings resistance, no-load losses and load losses.
• Measurement of no-load losses and load losses according to Regulation on ecodesign requirements for power transformers (EU) No 548/2014.
• Temperature-rise test on liquid immersed transformers and dry-type transformers accoridng to IEC 60076-2 and IEC 60076-11.
• Electrical type tests and routine tests on power transformers according to IEC 60076-3 Standard including lightning impulse test, chopped impulse test, partial discharge measurement.
• Determination of sound levels of power transformers according to IEC 60076-10.
• Temperature-rise tests, dielectric tests, verification of degree of protection and other tests on prefabricated distribution substations according to IEC 62271-202 and IEC 62271-212 Standards.

Capabilities & Products
• Three-phase and one-phase transformers with frequency 50 / 60 Hz
• Rated power from 1 kVA to 10 MVA
• Rated voltage up to Um 72.5 kV
• Distribution transformers, liquid-immersed power transformers
• Dry-type power power transformers
• Prefabricated substations 5 MVA Um 36 kV 50 / 60 Hz
• Low voltage power transformers


Dielectric type tests, measurement of resistance, temperature-rise test, verification of degree of protection IP and IK codes, dielectric tests on auxiliary circuits, partial discharge measurement, functional tests, environmental tests and other tests on MV Switchgear and controlgear according to IEC 62271 Series Standards.

Temperature-rise tests, dielectric tests, verification of degree of protection IP and IK codes, resistance measurement and other tests on low voltage switchgear and controlgear assemblies according to IEC 61439-1 Standard.


The event of a lightning strike on an aircraft can lead to a possible failure of the structure or the equipment among other elements of the aircraft. LCOE has assisted their customers by performing lightning strikes tests on their products for more than 20 years. 

Lightning Direct Effect tests according to EUROCAE ED105 and ED84 standards and to RTCA-DO-160 Standard are performed in LCOE High Current Laboratory. High Voltage Tests and High Current Tests on different elements of the aircraft, such as radomes, winglets, rotor blades etc.


A surge arrester is a device to protect electrical equipment from over-voltage transients caused by external (lightning) or internal (switching) events. Also called a surge protective device (SPD) or transient voltage surge suppressor (TVSS), this class of devices are used as a protection for equipment in power transmission and distribution systems.

Electrical type tests on metal-oxide surge arresters for AC systems according to the standards descirbed below are performed at LCOE High Voltage Lab and Current Impulses Lab.

Reference Standards
• IEC 60099-4 and IEEE C62.11 Standards. Metal-oxide surge arresters for AC systems.
• IEC 61643 Standard. Surge Protective Devices connected to low-voltage systems.
• UNE-EN 50539-11:2013. Requirements and tests for SPDs in photovoltaic applications.

Capabilities & Products
• Metal-oxide surge arresters for AC systems up to 200 kA Um 245 kV
• Surge Protector Devices connected to low a.c. voltage systems, d.c. voltage systems, photovoltaic installations.


Dielectric type tests on insulators for overhead lines for a.c. systems with a nominal voltage above 1 000 V according to the following Standards:

  • IEC 60383-1 Standard. Ceramic and glass insulators.
  • IEC 61109 Standard. Composite suspension and tension insulators.
  • IEC 60168 Standard. Tests on indoor and outdoor post insulators.
  • IEC 60660 Standard. Tests on indoor post insulators of organic material.
  • IEC 62231 Standard. Composite station post insulators for substations with a.c. voltages greater than 1 000 V up to 245 kV.

RIV measurement on high voltage insulators according to IEC 60437 Standard.
Type tests and routine tests on insulated bushings for alternating voltages above 1000 V according to IEC 60137 Standard.


HV and MV cable systems are very important elements needed for the electrification of large cities, industrial areas and the expansion of the power supply networks. We can perform routine tests and electrical type tests on cable systems up to Um 245 kV to verify the design and manufacturing of LV, MV and HV power cables with extruded insulation and their accessories.

Reference Standards & Products
• IEC 60502 Standard. Power cables with extruded insulation and their accessories for rated voltages from 1 kV (Um = 1.2 kV) up to 30 kV (Um = 36 kV)
• IEC 60840 Standard. Power cables with extruded insulation and their accessories for rated voltages above 30 kV (Um = 36 kV) up to 150 kV (Um = 170 kV)
• IEC 62067 Standard. Power cables with extruded insulation and their accessories for rated voltages above 150 kV (Um = 170 kV) up to 500 kV (Um = 550 kV)
• HD 629.1 S3 Standard. Test requirements for accessories for use on power cables with extruded insulation of rated voltage from 3.6/6(7.2) kV up to 20.8/36(42) kV
• IEC 61238-1 Series Standards. Compression and mechanical connectors for power cables for rated voltages up to 30 kV (Um = 36 kV). Heating cycles test, measurement of resistance and short-circuit tests.


In the event of a lightning strike on a building, the strike needs to be conducted in a way that ensures the safety of the equipment and the people inside it.

To ensure this purpose, the lightning protection system components need to be tested according to certain standards. LCOE provides testing services according to the following:

• UNE EN 62561. Connection components, conductors and earth electrodes, isolating spark gaps...
• UNE 21186 / NFC 17 102. Early Streamer Emission (E.S.E) lightning rods.


Live-line working, also known as hotline maintenance, is the maintenance of electrical equipment, often operating at high voltage, while the equipment is energised. Live-line maintenance techniques are used in the electric power distribution industry to avoid the disruption and high economic costs of having to turn off power to customers to perform essential periodic maintenance on transmission lines and other equipment. Electrical type tests and leakage current measurements on live working devices are performed on HV and MV testing areas of LCOE Laboratory.

Reference Standards & Products
• IEC 61243-1 Standard. Capacitive voltage detectors for voltages exceeding 1 kV AC.
• EN 50508 Standard. Multi-purpose insulating sticks for electrical operations.
• IEC 61057 and ANSI A92.2 Standards. Insulating aerial devices for mounting on a chassis.
• IEC 62192 Standard. Insulating ropes used during live working procedures.
• EN 3-7 Standard. Dielectric test on portable fire extinguishers.

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