1. ASSEMBLY, INSPECTION AND ADJUSTMENT OF RELAY PROTECTIONS UP TO 400 KV

1. Current protections;
1.1. Over-current protections and segments;
1.2. Over-current protections;
1.3. Earth protections.
2. Remote protections:
2.1. Remote protections without phase action;
2.2. Remote protections with phase action;
2.3. Interlock at damages in voltage chains.
3. Differential protections:
3.1. Differential protections of electric power lines;
3.2. Differential protections of busbars.
4. Automatic frequent separation.
5. A device for reservation of failure of the circuit - breaker.

2. RECONSTRUCTION OF ELECTRIC POWER SUPPLY UNITS OF 0.4 kV, 6 kV, 20 kV

On the basis of vacuum and SF6 circuit breakers in plant conditions prototypes have been devised which are aimed at replacing the currently operating house-load supply switchgears installations at the Thermal Power Plants and in distribution systems.
The prototypes are designed based on the existing structure of switchgears, changing only the breakers and, if necessary, the protections.
The repair works of the present installations are performed only if there is technical and economic advisability and depending on the quantity of spare parts needed for the replacement.

3. METHODS AND EQUIPMENT FOR PURIFICATION OF TRANSFORMER OILS ARE DEVELOPED BY OUR COMPANY
All kinds of transformer oils are to be re-cleaned after being in operation for ten and more years in order to remove completely or partially the age-attached products.
The quality of the treated oils is brought up to the quality parameters of new oils according to the IEC standard. We have purified 500 tons oil up to now. This oil is used in transformers of up to 220 kV.
The used method is environmentally sound.

4. DIAGNOSTICS AND REPAIRS OF SURGE ARRESTERS AND MEASURING TRANSFORMERS

The diagnostics is grounded on thermovision and specific measuring of the electric parameters thus determining the serviceability, and in case of a breakdown or short rest lifetime a replacement is done.

5. REPAIRS OF OVER-HEAD LINES

The repair works of power lines up to 110 kV are carried out with rehabilitation of the insulation system by using new glass or polymer insulator circuits.

DIT - M Ltd. has branch offices and workshops in the region of the Thermal Power Plant Maritsa East 2, in the town of Dobritch and in other towns and industrial centers.

In its activity DIT - M Ltd. has reliable foreign partners:
· Scientific Electric Institute of Moscow;
· Moscow plant Izolator JSC;
· Transformator JSC - Toliaty, Russia;
· DIACS JSC;
· Electrosila JSC - St. Petersburg, Russia;
· Energoservise JSC - St. Petersburg, Russia;
· Zaporijsky Transformer Plant - Zaporijie, Ukraine;
· Company IPDD - Minnesota, USA;
· THYSSEN GmbH - Germany;
· PASSONY & VILLA - Italy;
· ABB - Check Republic;
· Company DIVECO - Slovenia.
· ŅESMEC - Italy;
· DALEKOVOD - R. Croatia;
· Fabrika Mernih Transformatora - Zaicher, Jugoslavia