We provide clients solid expertise and long experience in all tasks related to the design, construction, documentation, and measurements of substations. Our clients include industries, plants, and electricity companies. In addition, we provide contractors wit planning of subcontracting.
Our services are nationwide and tailored to cater for every client’s case-specific needs.
Substations and primary circuit design
Primary circuit designs determine how substations look from the outside. The design depicts positions and heights of the equipment as well as dimensions and installations of main circuits. The primary circuit design provides initial information for steel structure, ground structure, and foundation designs. Design also considers distances determined for the substation and issues related to environmental safety.
Design of protection and control circuits
The main part of the electric power grid protection and automation system is located in substations. Circuit diagram and wiring tables, cable lists, pull lists, cabinet manufacturing drawings and instrument lists are prepared for construction of systems and making changes to them.
Substations and grounding design
The grounding of electrical equipment must be designed so that the system does not pose danger to its users or to people and animals moving in vicinity. A grounding design ensuring high-quality and safe use requires profound know-how and experience in measuring, grounding modelling as well as in calculation and analysis of hazardous voltages.
Design of AC/DC-systems
For the operation of the equipment at the substation auxiliary power is required and therefore the substation must have functioning alternating current and direct current systems. Alternating current systems are used for maintaining regular real estate systems and charging batteries. All systems that are critical for operation are in turn secured with a direct current system. We provide the preparation of circuit diagrams, wiring tables and other necessary drawings for AC/DC systems. If necessary, we also carry out the required dimensioning calculations.
HVAC design for central equipment buildings
Substations require regular technologies, and therefore heating, water, air conditioning, and electricity designs must be drawn for the buildings. HVAC technical systems are often connected to the substation’s automation system. We are responsible for preparing professional electrical design for substations and take care of the connections to the automation system. With regards to other plans and systems, we use our long-term subcontracting partners.
Design of construction, foundations, and steel structures
We provide design of construction, foundations, and steel structures based on common and proven structures typically used in substations. Where necessary, we use in preparation of the designs our reliable subcontracting partners.
Project planning and preliminary designs for substation
In the project planning phase of a substation, the need for and costs of the project are evaluated, as well as alternatives for the construction. Based on the project plan, a more detailed preliminary plan is drawn up, on the basis of which a well-grounded investment decision can be made.
Specification of technical requirements for substation equipment and main transformers
When procuring substation equipment, technical requirements thereof must be specified to ensure that the acquired equipment meets actual needs of the client. Specified technical requirements include product functions, standards, main dimensioning values and other requirements affecting the selection of a suitable product.
Hazard and interference voltage surveys of transmission lines and substations
We carry out inspections and investigations of hazardous and interference voltages. Calculation quantities we master include, for example, equivalent grounding impedances, reduction factors, and calculated induced voltages. Surveys map how transmission lines and substations affect the surrounding land area and electricity and telecommunications network. Reports present measures, how to identify hazardous objects and implement protective measures setting the foundation for the grounding design.
Short-circuit force calculations for rail structures
In case of short circuits, high mechanical forces are applied to rail structures and transmission cables. When dimensioning rails and their support structures, these forces must be considered. We carry out the short-circuit forces calculations of rail structures according to standard IEC 865-1.
Substation procurement documents
Procurements for a substation require preparation and management of several different documents, including, inter alia, a request for tender, contract drafts, procurement program, procurement responsibility table, technical specifications and preliminary designs. We prepare procurement documents professionally and based on our long experience.
Reviewing of plans and delivery control
We are responsible for delivery supervision and make sure that the quality, quantity, price, and delivery time are followed. In case of problems, we notify the supplier. In assessment of the end-result, it should be noted that substations are built for 50 years, which creates specific requirements for the quality and modifiability of the solutions implemented at the station.
Updating the documentation of substations
We make sure that the electronic images of the substation correspond to reality. Our designer visits the station to compare the accuracy of the archived documents and the station’s documents. We take care of the correctness of entries and document required changes. If necessary, we will also carry out inspection visits to the substation further on.
Entering red pen markings in the blueprint
At the end of the project, we are responsible for entering red pen notices made in blueprints and documents to final updated files and documents transferred to client’s information systems. If necessary, we store updated paper versions in folders on site. We also repair red-pencilled issues during maintenance and provide help related to drawing and updating plastic pictures.
Converting documents to electronic format and file conversions
The use of electronic documents is easy and efficient. We convert all paper documents and plastic images into electronic format and, if necessary, we also help in to convert already existing files into the desired format.
Taking photos of substation systems
Substations are often located far from offices. The photos make it easy to check the actual condition of the substation. We take photos of substation systems with a system camera being able to safely move around a substation as we know the substation’s equipment. We deliver the photos organized in folders and grouped by topics.
Grounding impedance measurements
The high-voltage standard SFS 6001 requires monitoring of grounding systems throughout the life cycle of the system. We provide grounding impedance measurements from large, interconnected grounding systems to a single grounding electrode. For determining the total grounding impedance of large groundings, we use the frequency-selective V/A method, which typically uses 20-400kV open wires and field cables as measuring conductors. The inflection point method with different power supply wire lengths and the V/A method are used in the determination of compact grounding systems. The turnkey measurement report includes an overview of compliance with the standards and regulations at the site, as well as a hazardous voltage calculation and analysis.
Contact voltage measurements
Electrical safety regulations require that the performance of the grounding system is at a sufficient level and that in the event of a failure of the electrical system, there are no hazardous or disturbing voltages. We perform contact voltage measurements and inspections as well as voltage propagation measurements using a frequency-selective method. This measurement may also be carried out combined with the grounding impedance measurement using the same measuring wire arrangements. If necessary, we also use various measurement tests, such as the contact voltages caused by the actual ground current of the distribution network.
Soil resistivity measurements
We perform measurements of the soil resistivity in the terrain. Grounding design will be based on the measurement results giving our experienced measurers required competence to make the necessary observations about the objects to be considered in terrain planning. Combined with the same measurement, we can, if necessary, collect and prepare maintenance or location information.
Measurements of grounding continuity
The continuity of the grounding of a high-voltage system must be monitored on regular basis. Grounding system connections must have good electrical conductivity to minimize the temperature rise caused by the fault current. If the grounding is implemented with a single conductor, it is recommended to carry out measurement every 6 years. For grounding connections with two conductors, the inspection interval is 12 years. We measure the continuity of grounding and equipotential bonding systems with both DC and AC current. We usually perform the measurements with a DC current of at least 100 A, but our equipment can measure larger currents, for example for establishing weaknesses in the grounding.
Ensuring the interconnection of grounding
We measure the continuity between different grounding units, for example within the distribution network, using the transmission network as measuring conductor. We can make the necessary calculations and specifications using the measurement results, for example the specification of an extensive, interconnected grounding system according to the SFS 6001 standard.
Measurement of various lead quantities
We measure the actual forward, reverse, and neutral impedances of underground cables and open wire routes for protection calculations and protection layouts – a typical need may be 110 kV for underground cable route with grounding monitoring and counter stations. We measure reduction coefficients of lightning and other galvanic paths and conductors, and we also provide related calculations. In addition, we measure and calculate the voltages caused by various inductive, capacitive, and conductive couplings.
Substations & electric and magnetic fields
We carry out electric and magnetic field measurements in all kinds of objects. Results are analysed, compared with limit values of the regulations and reported.
Substations and testing of measuring transformers
We test the conversion ratios and accuracy classes of current and voltage transformers with our measuring equipment. The testing of measuring transformers is a recommended and even required procedure for substation commissioning tests to detect possible manufacturing, transportation, or installation damages.
Other services
We also provide other electrotechnical measurement and expert services: the planning of various measurement arrangements and dangerous voltage and grounding issues; consulting and training. We also do overall delivery analysis, including advance planning and safety inspections, instructions, measurements, calculations, and reporting. We have provided complex service packages for various research projects.
Efficiency for the phases of the electricity network’s life cycle
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How can I help?
Esa’s substation expertise is top class. He has solutions for new and old substations and everything in between. You should also contact Esa regarding measurement needs.
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Brief in English
Despro provides professional services for energy and telecom industries. We offer our services for network construction companies, network owners and other stakeholders
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