RST Net provides services of electricity equipment for companies in the energy industry and places great emphasis on preventive maintenance in order to prevent breakdowns and power outages.
Scenario analysis
RST Net provides a situation analysis of all the major links of the power circuit of the electricity transmission and distribution systems.
An important aspect of ensuring security of electricity supply is the condition analysis of electrical installations necessary to reduce the risk of unexpected failures in the electrical system. RST Net has carried out condition analysis in the electricity sector since 1999 and has advanced measurement instruments for condition analysis and with employees with expertise in this field the company can provide all services and advice on condition assessment based on the results of analyses.
When assessing conditions, it is important to take measurements of new equipment before entering operations, the so-called "fingerprint", for comparison with later measurements. This allows you to see how aging or wear and tear of equipment develops and can be intervened before failure occurs with associated operating disturbances.
When making a physical diagnosis, it is important to follow the manufacturer's instructions for the equipment and, where appropriate, the standards. Also, the interpretation of results is an important aspect of condition diagnosis and therefore training and education of employees is of utmost importance.
Measurement results and analyses are delivered to the customer in a high-quality reporting format where the main findings of the condition analysis are summarized.
The measurement of the circuit breakers measures, inter alia, the operation of the drive mechanism of the switch as well as the resistance of the power contacts in the switch and their displacement during breaks and couplings.
It is important to measure new switches before entering service to own the "fingerprint" of the switch for comparison for future measurements. Regular measurements of circuit breakers are necessary to monitor the operation of, for example, solvent solenoids and increased drag in the power contacts of the switch.
RST Net provides all services for the measurement and condition analysis of circuit breakers. Measurement results and analyses are delivered to the customer in a high-quality reporting format where the main findings of the condition analysis are summarized.
For more information on measuring techniques, measurement functions and instruments for circuit breaker condition analysis, see HERE
One of the most proven methods of condition assessment of oil-filled transformers is the analysis of gases in samples taken of the transformer oil.
Cores and coils are commonly referred to as the active components of oil-filled transformers, but the core is made of steel and coils made of aluminium and/or bronze windings insulated with paper and transformer oil. The paper is the solid insulation of the coils and the oil is both the insulating and refrigerant of the active part. By analysing gases and trace elements in the taken oil samples, the condition of the active component can be monitored without intervention in the operation of the transformer, no lack of voltage only going into the so-called bottom valve of the transformer tank to obtain a sample of the transformer oil.
RST Net provides all services relating to the taking and analysis of oil and paper samples and interpretation of analytical results in collaboration with reputable foreign laboratories.
With oil analysis, a so-called Furfural analysis can also be performed to analyze the condition of paper in the insulation of the coils and estimate the DP value from the results of the analysis.
The DP value (DP = Degree of Polymerization) indicates the average value of the number of linkages in a long chain of atoms in cellulose molecules in the paper insulation of the transformer, while the number of such links in one molecule is about 1400 in new insulation paper. During the aging of the paper insulation of the transformer, these links give way and the molecules decompose, the DP value decreases. This decomposition of paper insulation occurs during a chemical reaction where heat has a decisive effect, higher temperatures increasing the rate of the reaction. By assuming a separate operating assumption (load), it is possible to estimate the service life of voltages if the DP value is known.
If it is possible to access and obtain a sample of the insulation paper of the transformer, the DP value may be analysed by the laboratory. Since it is difficult to access paper surrounding twists, the condition of voltages can also be detected by measurements. The main measurements are so-called "Tan Delta" measurements, which measure the capacitance between high voltage and low voltage windings as well as the capacitance between the winches and the voltage tank. From these values it is possible to estimate the condition of the transformer, if historical measurements are available for comparison and see trends in measurement results. It is common for such measurements to be made every 5-10 years to get a history of paper condition.
One aspect of the voltage condition analysis is the measurement of high voltage outlets penetrators on the windings of the transformers, on which a special test button is provided for connection to the measuring equipment. These measurements are repeated every 5 – 10 years.
RST Net provides all other services for the measurement and condition analysis of power transformers. Measurement results and analyses are delivered to the customer in a high-quality reporting format where the main findings of the condition analysis are summarized.
Further information on measurement techniques, possible measurement operations and instruments for condition analysis of power transformers can be found HERE.
RST Net has measurement equipment for power cable testing and condition analysis based on very low frequency (VLF) Tan Delta measuring technology, an accurate and non-destructive method that provides good information on the degree of ageing in power cable insulation.
Measuring and condition analysis of high voltage and low voltage cables can assess the condition of the cables, identify weaknesses in the cables and take appropriate action before failure occurs, avoiding unnecessary costs and operating interruptions. Such information is important for condition-based and cost-optimized maintenance systems.
It is important to take the "fingerprint" of strings before entering service to compare for future measurements.
RST Net provides all power cable measurement and condition analysis services. Measurement results and analyses are delivered to the customer in a high-quality reporting format where the main findings of the condition analysis are summarized.
Further information on measuring techniques, possible measurement operations and instruments for power cable condition analysis can be found HERE.
Repair and Maintenance
RST Net provides services in the maintenance, upgrade, repair and new construction of equipment for the energy sector.
RST Net prides itself on providing robust maintenance and repair services but also offers emergency services in the event of breakdowns in critical parts of the electricity systems of energy companies and industrial plants.
The housing RST Net is specially designed for the uptake of power transformers which requires high ceiling height and lift capacity. The bridge crane in Álfhella 6 has a lifting capacity of up to 60 tons.
The company has a lot of specialized instrumentation and measurement equipment including 5 oil refineries of different sizes and types, including a new and complete Micafluid device that has a higher capacity than any other oil refinery in the country.
RST Net is responsible for refurbishing and upgrading older high voltage equipment as well as assistive and control equipment.
The aim is to extend the service life, increase reliability and safety and ensure efficient operation of electricity systems.
RST Net also analyses the condition of transformers and distribution transformers and replaces them on request, as well as upgrading circuit breakers in transmission and distribution systems.
RST Net provides fault detection of all major links of the power circuit of the electricity transmission and distribution systems.
Electrical equipment failures can occur unexpectedly, in which case you need to identify where the fault is and its nature. RST Network on trouble diagnostic instruments also used for condition diagnosis. The interpretation of results is a very important part of failure diagnosis and for identifying the location and cause of failure.
Failure detection of power transformers uses specialised measurement and computer equipment. To diagnose failures, you need to look at the results very carefully because several factors can affect the diagnosis of what is actually wrong. This may include, for example, failures in insulation or heat in metals, i.e. in the conductors or core of the transformer. To find transformer failures, its active parts (core and coils) need to be hoisted more often than not from a transformer tank. In the RST Net workshop this is possible as the workshop is equipped with a powerful 2 x 30 ton bridge crane and with sufficient ceiling height.
RST Net is represented by Maschinenfabrik Reinhausen (MR) and, amongst other things, provides specialist assistance in the uptake and maintenance of stage changes.
A staggering switch is the only moving object in transformers, but it has the function of changing the winding ratio of the transformer to maintain the correct voltage on the system. Generally, step changers and oil must be replaced after 70,000 – 100,000 splits, or every 7 years, whichever comes first.
RST Net has been servicing staged equipment since 2000 and therefore has both knowledge and experience in servicing staged equipment.
A staggering filter device for purifying the oil can be supplied in a closed system for the stage switch. If there are multiple divisions per year, then MR recommends a step-up after 150,000 splits or after 7 years, whichever comes first.