Service and maintenance contracts

An advantage that pays for itself every day!

Client-specific

By signing up for a service and maintenance contract that is customised for your individual needs, you can minimise the risks of expensive downtimes and benefit from the quickest possible intervention if problems should occur.

Experience pays!

With our experienced specialists, we are able to offer you ideal service. We ensure that your systems remain available and reliable, around the clock! As part of our repair and maintenance work, we check your system for signs of wear and possible sources of faults. You can benefit here from our expertise as a systems manufacturer, the experience of our service specialists and the application of the most modern measurement and analysis equipment.

Your advantages

• Shorter reaction times
• Reduction of unplanned downtimes thanks to early detection
• Reduction of service costs if faults do occur
• Higher transparency in operating costs
• Investment security
• Tips and tricks from our on-site experts
• Contract partners enjoy top priority
• Planning of maintenance periods

Our experience shows a service and maintenance contract guarantees reliable operation thanks to continuous checking of your system – this helps to avoid many problems and their consequences!

Transformer service

Technical service for the entire service life of your transformer!

Transformers are subject to a natural ageing process. For this reason, they require scheduled testing and checking. This cycle interval is mainly dependent on the location and operating conditions, as even an issue such as significant dirt can endanger operational reliability.

We offer needs-based solutions here:

1. Inspection and cleaning of transformers
2. Cast resin insulation testing
   • Testing and measurement of insulation resistance of MV transformers incl. measurement protocol
3. Monitoring of insulating oil as per DIN EN 60422
   • Standard testing of all transformers, converters and switching devices filled with mineral oil up to 72.5 kV
     Test items:
     • Colour and appearance (ISO 2049)
     • Breakdown voltage (IEC 60156)v
     • Water content (IEC 60814)
     • Neutralisation value (IEC 62021-1)
     • Dielectric loss factor (IEC 60247)
4. Insulating oil preparation/drying in oil transformers
   • Preparation of oil to a breakdown strength of at least 60 kV at 2.5 mm electrode separation using mobile preparation equipment
5. Sealing work
   • High voltage and low voltage bushings, cover seals, Buchholz screw connections, viewing glasses, off-circuit tap changers etc.
6. Retrofitting work
   • Buchholz protector relay, hermetic protection block, pressure switch, thermometer, air dehumidifier, vibration damper
7. Conversion work
   • Conversion to touch-proof plug-in bushings (MV side) and protection against touching (NV side)

Retrofitting

Are your systems still up to date?
Retrofitting? Modernisation?

And of course, we don’t just mean a little bit of cosmetics here and there. We provide the ultimate innovation update for your system and bring it in line with the state of the art. We can replace outdated parts with new components and prepare your system for the future!

This brings important advantages for you:

• Increased system and operational reliability
• Adaptation to current standards
• Replacement of modules for which replacement parts are no longer available
• Retrofitting of automation technology
• Reduced investment costs relative to the purchasing of new systems

Retrofitting is thus a cost-effective and efficient way to modernize your systems.
Get in touch with us right away!

Calculation of pressure situation in medium-voltage switchgear rooms

It doesn’t work without pressure!

Releasing pressure in an uncontrolled manner can be fun when you have something to celebrate! However, it’s better if you know the pressure situation in your switchgear. After all, it would be no reason to celebrate if something went ‘pop’ in your switchgear …

Calculation of pressure situations for DRIESCHER switchgear in medium voltage rooms

An arcing fault cannot be fully ruled out when operating electrical systems. This type of fault represents a considerable load for the switchgear and switchgear building, and can also be a hazard for persons who are present.

What must be taken into account for new systems?

When installing a new system, the pressure situation should be calculated in advance so that it can be taken into account in the construction work.

What should be taken into account when replacing and renewing a switchgear?

If an existing, old switchgear is replaced by a new one, the pressure situation will also change as the new switchgear generally has a higher installed power. In this case, it is particularly recommended that a new pressure calculation be carried out to ensure personal safety.

As per DIN VDE 0101 Item 6.5.3.1, the internal pressure caused by a short-circuit arc is to be taken into account when constructing buildings. The overpressure in a building can only be determined by carrying out a pressure calculation.

Pressure limitation in a building can be achieved using pressure relief devices. The effect of pressure relief openings in the case of an arcing fault in a medium-voltage switchgear can be calculated as part of a pressure calculation.

By applying the analogy between the electrical field and the flow field, pressure distribution processes can be modelled using known grid data for the electrical technology. The non-linearities that occur in pressure networks require a computer-aided, interactive solution method.

Our program has been configured for the calculation of arcing power and pressure distribution processes. Pressure waves, i.e. runtime effects due to transformer waves in a gas and reflections at building walls, are taken into account with the aid of transformer wave elements in the pressure network – it then becomes possible to determine the pressure as a function of both position and time.

Sources of error immediately visible!

State of the art

Thermography is state of the art today, as it is an efficient and cost-saving means of safely assessing electrical systems and equipment.

Your advantages at a glance

• Early detection of weak points and faults, thus increasing system safety
• Testing during normal operation, i.e. no production downtime
• Avoidance of consequential damage
• Areas that are difficult to access can also be inspected
• Reduction of the risk of fire and accidents
• Maintenance can be planned
• Predicted service life of operating equipment
• Possibly more favorable classification by your insurer
• Concrete classification into fault groups

The possible applications

• Medium-voltage switchgear
• Low-voltage switchgear
• Type-independent transformers
• Sub-distribution boards, control cabinets
• Cable and power installation, overhead lines
• Electrical machines and drives

Although thermography cannot replace periodic inspections, it is a very good way of providing a concrete assessment of the condition of your systems during normal operation.