Surge Counters | MV HV Surge Arrester Monitors for High Voltage Power Systems

ABB surge counters

Surge Counters for Surge Arresters | ABB EXCOUNT

Surge Counters

Monitoring the health of surge arresters

Thorne & Derrick distribute the complete range of ABB Medium & High Voltage Surge Arresters (MV-HV) and accessories (including Surge Counters) for the protection of MV-HV Electrical Power Systems, typically operating at 11kV/33kV and up to 66kV.

Well-designed and tested, ABB surge arresters are maintenance-free and can reasonably be expected to have a long service life. However, the condition of these surge arresters should also be monitored to ensure the most ultimate protection against a costly unplanned power outage. This can be achieved using the ABB EXCOUNT range of surge counters and monitors.

ABB Surge Arresters

ABB Surge Arresters | Protection of MV & HV Electrical Power, Substation, Switchgear & Transformers

Surge arresters present a high impedance at normal service voltage such that they behave as an insulator for the majority of their life. This is necessary to assure a long life for the surge arrester itself as well as stability of the electrical network as a whole. A deterioration of a surge arrester’s insulating properties is therefore important to detect early before the situation becomes acute.

In order to truly evaluate the health of an arrester, testing made as routine during manufacture would need to be performed. However, such testing is not practical to make in the field and removal of the arrester to a HV lab is deemed uneconomic.

Instead, in-service diagnostic is required.

Surge Counters Benefits

The ABB state-of-the-art product family EXCOUNT has the full range of surge counters and surge monitors to cater for all customer needs – from simple discharge operation count (EXCOUNT-C) through leakage current measurement (EXCOUNT-I), remote wireless monitoring and diagnostics (EXCOUNT-II) to online real-time monitoring, diagnostics and analysis (EXCOUNT-III).

  • Proven safe short-circuit design
  • No voltage added to the residual voltage of the arrester
  • Maintenance free
  • Easy to install
  • Simple to use
EXCOUNT C Surge Counters | MV HV Surge Arrester Monitors for High Voltage Power Systems EXCOUNT I Surge Counters | MV HV Surge Arrester Monitors for High Voltage Power Systems EXCOUNT II I Surge Counters | MV HV Surge Arrester Monitors for High Voltage Power Systems EXCOUNT III I Surge Counters | MV HV Surge Arrester Monitors for High Voltage Power Systems

EXCOUNT Range Overview Of Counters for Use with Surge Arresters

Please contact Thorne & Derrick should you require any assistance with the selection, specification or purchase or Surge Counters from the EXCOUNT range of products manufactured by ABB.





Surge registration
 – Number of impulses Yes Yes Yes Yes
 – Impulse amplitude classification Yes Yes
– Impulse amplitude measurement Yes
(also available without)
– Time stamp Yes Yes
– Wave Steepness Yes
(also available without)
– Advanced Surge analytics Yes
(also available without)
Current measurement
– Total current Yes
(also available without)
Yes Yes
– Resistive leakage current Yes
(also available without)
– Overvoltage estimation Yes
(also available without)
– Online real time monitoring Yes
Display 6 digit,
electro- mechanical counter
6 digit,
Remote reading, PC connectivity Remotely monitored through network connection
Power Supply Not applicable Solar panel Solar panel and field probe 100-250 Volt, AC (50-60 Hz) or DC, Max. 5 Watt, Max 0.1 A

The EXCOUNT surge counter range draws upon over 70 years of experience by ABB in the development of arresters and associated accessories. Safety, functionality and longevity are key elements which are given priority in selection and design of components. In stark contrast to many other competing products, EXCOUNT has not neglected short-circuit safety which lies inherent in the design concept.

Advantages of the ABB surge counter range:
Surge Counters | MV HV Surge Arrester Monitors for High Voltage Power Systems

Highest personnel safety
  • Explosion-proof for short-circuit currents up to 65 kA.
  • Same safe performance as ABB arresters.
Negligible residual voltage
  • Does not reduce protection margins.
  • Minimized risk for injury in case of accidental contact during surges.
Maintenance free
  • Sealed components.
  • Requires no external power supply.
Long life
  • Moulded components, non-sensitive to humidity or temperature variations.
Universal application
  • All makes and types of gapless surge arresters.
  • All weather and temperature conditions.

The use of an impulse current transformer with a single-turn primary ensures that the voltage drop across the counter is negligible, even at the highest impulse currents encountered in service. This leads to added personnel safety and no increase in the protection level of the arrester. Since no gaps or series impedance are used, there is no risk of internal arcing and consequent explosive failure in the event of a short-circuit following an arrester failure.

All internal components are fully encapsulated in polymer throughout the EXCOUNT range. This provides sealing to IP67, which ensures no harmful ingress of dust or moisture as well as providing personal safety through complete protection against contact with the internals.

Surge Arrester Maintenance

The primary reason for the use of surge counters on modern gapless ZnO arresters is to check if a particular transmission line or phase suffers from an exceptionally high number of over voltages leading to arrester operation. If this is the case, whilst it validates the need for the arresters, use of some preventative countermeasures may be warranted to limit the number of surges. A sudden increase in the counting rate may also indicate an internal arrester fault, in which case the arrester should be investigated further.

External factors can place stresses on the arrester, potentially leading to its deterioration and ultimate overload, therefore it is important to draw up a schedule for regular checks. The older the arrester, the more regular these checks may need to be, since the statistical risk for overload increases with age.

As a guide, the following strategy is proposed to be made at regular intervals as required and determined by site availability and importance:

  • Visual inspection and possible cleaning
  • Diagnostics in advance of the designated lighting season and thereafter following periods with bad weather conditions.
  • Diagnostics after special fault conditions causing flashover in the network or TOV’s of high amplitude and/or long duration.



Thorne & Derrick provide competitive prices and fast delivery from UK and European stock for the complete range of ABB Medium Voltage Electrical Products – we distribute the most extensive range of LV HV Jointing, Earthing, Substation & Electrical Eqpt to the Power Transmission & Distribution industry in the onshore and offshore wind, solar, rail, oil/gas, data centre, battery storage and utility sectors. We service UK and international clients working on underground cables, overhead lines, substations and electrical construction at 11kV/33kV and up to EHV transmission and distribution voltages.

➡ Contact us for competitive prices on ABB Fuses, Surge Arresters, Surge Counters & Medium Voltage Electrical Equipment.