Service
RST Net is a pioneer in servicing electrical equipment for companies in the energy industry and places great emphasis on condition based maintenance to prevent breakdowns and power outages.
Condition Analysis
RST Net offers condition-based analysis of all the major links in power transmission and distribution systems of electricity.
An important aspect of ensuring the security of electricity supply is the condition analysis of electrical equipment, which is essential to reduce the risk of unexpected failures in the systems. RST Net has been performing condition analysis in the electricity sector since 1999 and deploys state-of-the-art measuring instruments for condition analysis and, with trained experts in this field, the company can provide all services and advice on condition assessment based on the results of the analyses.
During condition assessment, it is important to take measurements of new equipment before it is put into operation, a so-called "fingerprint", for comparison with later measurements. This way, it is possible to see how the aging or wear of the equipment develops and it is possible to intervene before a failure occurs with associated operational disruptions.
During condition analysis, it is important to follow the manufacturer's instructions for the equipment and applicable standards. Interpretation of the results is also an important aspect of condition analysis, and therefore training and education of employees is extremely important.
Measurement results and analyses are delivered to the client in a quality report format where the main results of the condition analysis are summarized.
Circuit breaker measurements include the operation of the circuit breaker's drive mechanism, as well as the resistance in the circuit breaker's power contacts and their movement during opening and closing.
It is important to measure new circuit breakers before they are put into operation in order to have a "fingerprint" of the circuit breaker for comparison before later measurements. Regular measurements of are necessary to monitor the operation of, for example, trip coils or to detect increased resistance in the circuit breaker's power contacts.
RST Net provides all services for measuring and condition analysis of circuit breakers. Measurement results and analyses are returned to the customer in a high-quality report format where the main results of the condition analysis are summarized.
Further information on measurement technology, measurement operations and measuring instruments for condition analysis of circuit breakers can be found HERE
One of the most proven methods for assessing the condition of oil-filled transformers is the analysis of gases in samples taken from the transformer oil.
The core and coils are often called the active part of oil-filled transformers, but the core is made of steel and the coils are made of aluminum and/or copper windings insulated with paper and transformer oil. The paper is the solid insulation of the coils and the oil is both the insulation and cooling medium of the active part. By analyzing gases and trace elements in the taken oil samples, the condition of the active part can be monitored without intervention in the operation of the transformer, no voltage loss, 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 related to the taking and analysis of oil and paper samples and interpretation of the results of the analyses in collaboration with reputable foreign laboratories.
With oil analysis, it is also possible to perform a so-called Furfural analysis to analyze the condition of the paper in the insulation of the coils and estimate the DP value based on the results of the unit.
The DP value (DP = Degree of Polymerization) indicates the average number of links 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 insulating paper. As the paper insulation of the transformer ages, these links give way and the molecules break down, the DP value decreases. This breakdown of the paper insulation occurs in a chemical reaction where temperature has a decisive effect, higher temperatures increase the speed of the chemical reaction. By giving operating conditions (load), it is possible to estimate the service life of the transformer if the DP value is known.
If it is possible to obtain and obtain a sample of the transformer's insulating paper, the DP value can be analyzed by a laboratory. Since it is difficult to access the paper surrounding the windings, it is also possible to analyze the condition of the voltages by measurements. The main measurements are the so-called "Tan Delta" measurements, where the capacitance between the high-voltage and low-voltage windings is measured, as well as the capacitance between the windings and the voltage tank. Based on these values, it is possible to estimate the condition of the transformer, if there are older measurements for comparison, and to see trends in the measurement results. It is common for such measurements to be made every 5-10 years to obtain a history of the condition of the paper.
One aspect of analyzing the condition of the voltages is measuring the through-holes for the high-voltage outlets on the windings of the transformers, which have a special test button for connection to measuring equipment. These measurements are repeated every 5 – 10 years.
RST Net provides all other services for measuring and analyzing the condition of power transformers. Measurement results and analyses are delivered to the customer in a high-quality report format, where the main results of the condition analysis are summarized.
Further information on measurement technology, possible measurement operations and measuring instruments for condition analysis of power transformers can be found HERE.
RST Net has measurement equipment for testing and condition analysis of power cables based on Very Low Frequency (VLF) Tan Delta measurement technology, which is an accurate and non-destructive method that provides good information about the level of aging in the insulation of power cables
With measurements and condition analysis of high-voltage and low-voltage power cables, it is possible to assess the condition of cables, identify weaknesses in the cables and take appropriate measures before failure occurs and avoid unnecessary costs and operational disruptions. Such information is important for condition-based and cost-optimized maintenance systems.
It is important to take a "fingerprint" of cables before they are put into operation for comparison for later measurements.
RST Net provides all services for measurement and condition analysis of power cables. Measurement results and analyses are delivered to the customer in a high-quality report format, where the main results of the condition analysis are summarized.
Further information on measurement technology, possible measurement operations and measuring instruments for condition analysis of power cables can be foundHERE.
Repairs and Maintenance
RST Net provides comprehensive maintenance, refurbishment, repair and installation services for electrical equipment used throughout the energy sector.
The company has built a strong reputation for delivering reliable maintenance and repair services, while also offering rapid emergency response when critical equipment fails within utility networks or industrial power systems.
RST Net's facilities have been purpose-built for the maintenance and refurbishment of power transformers, with the high headroom and lifting capacity required for heavy electrical equipment. The overhead crane at the company's Álfhella 6 workshop has a lifting capacity of up to 60 tonnes.
The company maintains an extensive range of specialised tools, testing instruments and diagnostic equipment to support its engineering and maintenance services. This includes five transformer oil purification units of various capacities and configurations, among them a state-of-the-art Micafluid oil treatment system with a higher processing capacity than any other transformer oil purification unit in Iceland. RST Net's modern facilities and specialised equipment enable the company to undertake complex projects efficiently while maintaining the highest standards of quality, safety and technical performance.
RST Net undertakes the refurbishment and upgrading of ageing high-voltage equipment, together with associated protection, control and auxiliary systems.
The objective is to extend asset service life, improve reliability and operational safety, and maximise the efficiency of electricity transmission and distribution systems.
RST Net also carries out condition assessments of power and distribution transformers and provides complete refurbishment services where required. In addition, the company refurbishes and upgrades high-voltage circuit breakers used in transmission and distribution networks.
RST Net provides fault diagnosis services for all major components of electricity transmission and distribution systems.
Electrical faults can occur without warning, making rapid and accurate diagnosis essential to minimise downtime and restore reliable operation. RST Net uses advanced diagnostic and condition monitoring equipment to identify the location, nature and underlying cause of faults. Expert interpretation of test results is a critical part of the diagnostic process, ensuring that faults are accurately identified and appropriate corrective action can be taken.
For power transformers, RST Net employs specialised test instruments and computer-based diagnostic systems to assess equipment condition and detect developing faults. Diagnostic data is carefully analysed, as multiple factors can influence the results. Potential issues may include insulation degradation, localised overheating, or defects affecting transformer windings or the magnetic core. In many cases, a comprehensive inspection requires the transformer's active part (core and windings) to be lifted from the tank for detailed examination. RST Net's purpose-built workshop is fully equipped for this work, featuring a twin 30-tonne overhead bridge crane (2 × 30 tonnes) and sufficient headroom to safely handle large power transformers.
RST Net is an agent of Reinhausen GmbH (MR) and provides, among other things, expert assistance with inspections and maintenance of step changes.
The on-load tap changer is the only moving component within a power transformer. Its function is to regulate the transformer's turns ratio, thereby maintaining the required system voltage under varying load conditions. To ensure reliable operation, tap changers should typically be inspected and the diverter switch oil replaced after 70,000–100,000 switching operations or every seven years, whichever occurs first.
RST Net has been servicing on-load tap changers since 2000 and has extensive experience in the inspection, maintenance and overhaul of MR equipment.
RST Net also supplies and installs MR oil filtration systems for on-load tap changers. These systems continuously clean the insulating oil within the tap changer in a closed-loop process, reducing contamination and extending maintenance intervals. Where an oil filtration system is installed, MR generally recommends inspection after approximately 150,000 switching operations or every seven years, whichever occurs first.