DMOP-10-J Series
Station Class
Metal-Oxide Arresters


DMOP - 10 - J

Nominam Discharge Current : 10kA (8/20 µs)
IEC Line Discharge Class : 3
Energy Capability : 6.1 kJ/kV,
High Current Impulse Withstand : 100 kA-peak (4/10 µs)
Governing Specifications : IEC 99-4, TSEN 60099-4
Installation Site : Outdoor , 0-1200 m. altitude
Rated Frequency : 48-62 Hz

Metal Oxide Arresters

For arresters of type DMOP-10-J, DİSAŞ works with one of the world's leading suppliers of metal-oxide blocks. The arresters are manufactured under a technical co-operation afreement, whereby blocks are imported and the complete arresrters are then assembled and tested in DİSAŞ's own plant.

The quality of the varistors are guaranteed by design test reports from independent international laboratories, together with the qulity assurance system of the supplier. Meanwhile the varistors are also being testedat DİSAŞ's own laboratories upon arrival.

The use of highly non-linear metal oxide varistors permits the elimination of the internal series gap structure. The metal-oxide blocks combine protective characteristics with steady state performance to maximize protection over many years of service.

The varistors are put together by means of an epoxy-based wrapping system to from one single and rigid column of metal-oxide blocks. This special design not only ensures a higher reliability against high current surges, but it also enables the arrester to establish an increased steady-state performance.

Performance & Application

The gapless design means improved response to surges with fast rates of rise (i.e. Steep current surges). The stabilitiy of the protective characteristics of “DMOP” results in more consistent protection. This becomes increasingly important as equipment insulting capabilities degrade with time.

Metal-Oxide arresters “Maximum Continuous Operating Voltage” (MCOV) designates the maximum power frequency voltage that may be applied continuously through the arrester in service. Selection of the appropriate DMOP-rated voltage is made on the basis that the maximum line-to-ground voltage on the system does not exceed the MCOV of the arrester.


Rigit quality control standards ensure that all material conforms to exacting engineering specifications. Each complete arrester is subjected to seal leakage test to ensure the integrity of the sealing system and electrical tests to measure leakage current (resistive and capacitive components), reference voltage and partial discharge level of arrester.

All above mentioned tests are performed on each complete arrester according to IEC 60099-4.


Ground Lead Disconnector (GLD)

If required, DMOP-5 and DMOP-10 arresters can be supplied with a GLD device. GLD helps prevent line lockout by disconnecting a failed arrester from the system and serves as an indicating device that the failed arrester needs replacement.

The GLD that DİSAŞ supplies with its “DMOP” model arresrters is the only disconnector on the world which has a design test report from an independent international laboratory (CESI) for its operation.

GLD has to be earthed through the earth connection cable that is normally supplied with DMOP arresters.

Quality Assurance

Already established rules of extensive quality control in our production lines easily met the requirements of ISO-9002 certified by Turkish Standards Institution (TSE) since 1996.

Metal-Oxide varistors are purchased from one of the world's largest varistors manufacturers and they are tested as disaş laboratories upon arrival.

The varistors receice 100% routine tests before assembly into an arrester. According to the results of these tests, each varistor is selected for final assembly based on residual voltage, to assure the residual voltage of the complete arrester will not exceed standard values.

Final assembly, all routine tests required by IEC 60099-4 are performed on each arrester. Only the accepted complete arresters continue on for final packaging and shipping.

-Line Discharge Class (acc. to IEC 99-4) : Class 3
-TOV Capability : Duration: 1 sec : TOV = 1.43 x Uc
- Duration: 10 sec : TOV = 1.38 x Uc
-Long Duration Withstand Current : 610 A-peak, 2400 µs
-High Current Withstand Capability : 100 kA-peak, 4/10 µs

Ur : Rated Voltage of Arrester
Uc : Max. Continuos Operating Voltage of the Arrester (MCOV)
Ust : Steep Current Impulse Max. Residual Voltage, waveshape; 1/20 µs
Usw : Switching Current Impulse Max. Residual Voltage,waveshape; 30/60 µs
Ulight : Lightning Current Impulse Max. Residual Voltage ,waveshape; 8/20 µs
TOV : Temporary Overvoltage Capability

Note: If the required arrester's rated voltage is different than Ur values on the above list, please consult DİSAŞ.

Arrester Mounting

Standard Supply: DMOP-10-J arresters are base-mount type arresters. They shall be mounted with 4 pieces, M16 bolts (supplied with the arrester) on a concrete and/or steel foundation. M12 “earthing” bolt is also placed on the arrester base. Line connection shall be made by using cylindrical terminal bolt ( either φ 30 x 80 or φ 40 x 120 mm) on arrester top.

Optional Devices: Arresters with rated voltage (Ur) above 120kV are supplied with grading rings and its mounting parts. DMOP-10-J type arresters can be supplied with discharge counters (with or without current-meter) and insulating bases upon request.


©2011 Disaş AŞ