For industrials and utilities concerned about electrical equipment availability, reliability and cost, avoiding downtime – whether planned or unplanned – is essential. That is why there is a growing need to be able to perform predictive maintenance on a wide range of electrical equipment. A proactive rather reactive maintenance strategy can help you determine the overall health of your equipment, prioritize expenditures, stretch limited maintenance budgets, avoid costly downtime, and develop a plan for remedial action. 
Partial discharge (discharge activity) measurements have been made on rotating machinery for over 40 years. In most rotating electrical machines, there are numerous potential defect sites of discharge events: partial discharges in insulation; sparking between metal plates; arcing in contacts. The electrical insulation of these windings may be prone to partial discharge activity as a result of internal delaminations and as a result of surface or slot discharge. These kinds of partial discharge activity, when the machine is in normal operation, can result in significant deterioration over a period of time. Experience has indicated that partial discharge measurements can be useful for assessing the condition of complete windings as well as individual form-wound coils and bars.

• DIACS Technology gives absolutely new quality, placing outside sensors to any part of frame for on-line discharge defect’s location.
• All measurements are made on-line. That is why there is no need in the equipment’s shut down. Only permanently installed on-frame sensors are used.
• The new DIACS Technology detects all kinds of discharge events:  - PD in insulation, - Sparking in contacts, - Arcing in circuits.

The «Diagnostic Complexes and Systems» company (DIACS) has been established by the Ministry of Atomic Energetics, Industry of the USSR and Dr. Yuri P. Aksenov in 1989 for HV electrical equipment diagnostics of Russian nuclear power plants and is successfully operating until now having extensive working experience, new age technologies and recognition. Taking into consideration strong and exacting requirements towards industrial safety at APP special methods' synergy for on-line diagnostics have been developed to diagnose main NPP units (turbine generator, bus duct, step-up transformer and outdoor apparatus), which allows the use of condition-based maintenance at nuclear power plants in full measure. 
         DIACS experts conduct on-line discharge site pinpointing on equipment such as: 
                • Power Center Transformers
                • Potential/Current Transformers
                • Capacitors
                • Cables
                • Generators
                • Bus Duct
                • Motors
                • Switchgear 
Dr. Aksenov was the member of working group on standard preparation of IEEE Std 1434-2000 "Trial Use Guide to the Measurement of Partial Discharges in Rotating Machinery", thus the method used by DIACS was included into the international standard " IEEE Std1436 ". 
The main working field are power stations of Russia, however there are except works on the nuclear power plants of Russia, various companies and Industries (Volga Car Plant, Cherepovets Steel Plant; Nizhnekamsk, Novosalavatsky Nefteorgsintez (chemical industries); the pumping stations - determining reliability of oil transportation); much work is conducted abroad - in Asia, Latin America and in Europe. 
Intensive work in companies "Eni" (Agip, Europe) on transportation of mineral oil from seaport to the enterprises of oil refining is being developed. These are groups of enterprises in Sannazzaro, Tivoli, Venezia, Bussola, Cremona, and also groups “Polimer Europa”. These works are directed to the maintenance of reliability of the electric equipment in order to prevent the incidents leading emissions of products in the environment and floods of oil. The successful development of works was the basis of the special report «On Line PD Diagnostic on Medium Voltage Motors and Cable Lines: Useful Tool for the Maintenance Manager» which was made on ISEI 2004 in Indianapolis, the USA in September 2004.