Transformer Substation Design

Transformer substation design is the process of technically designing a substation infrastructure suitable for a facility’s energy demand, voltage level, load characteristics and operating conditions. As Pow-Sys Power Systems, we provide transformer substation project and design services across Türkiye for industrial facilities, factories in organized industrial zones, power generation plants, large commercial buildings and infrastructure projects. For related context, see Electrical Installation Periodic Inspection and Conformity Report.

A transformer substation project is not limited to preparing a layout drawing or a single-line diagram. For proper transformer substation design, the facility’s installed power, demand power, transformer capacity, short-circuit level, MV switchgear structure, cable routes, grounding system, protection scheme, maintenance access and official authority requirements must be evaluated together. For related context, see Electrical Contracting Services.

Before starting the project work, the facility’s energy demand and existing infrastructure are examined. The existing transformer substation, MV switchgear, power transformer, low-voltage panels, cable connections, compensation system, grounding arrangement, metering circuits and previous project documents, if available, are reviewed. This assessment is the basic step for correctly determining the need for a new project or revision. For related context, see High Voltage Operation Responsibility Service.

One of the first stages in transformer substation design is the correct determination of energy demand. Installed power, demand power, simultaneity, motor loads, production lines, backup supply requirements, capacity increase plans and critical loads are evaluated together. This study ensures that the transformer capacity and electrical infrastructure are selected in accordance with long-term operating conditions. For related context, see Grounding Installation Periodic Inspection.

Within the scope of a transformer substation project, single-line diagrams, load lists, transformer layout plans, MV switchgear arrangements, cable routes, panel layouts, grounding plans, cable sizing calculations, short-circuit calculations, voltage drop calculations and implementation projects can be prepared. When required, different project documents such as preliminary design, final design, implementation project, revision project and as-built project can also be created.

MV switchgear arrangement is one of the most critical topics in the transformer substation design process. The layout of incoming cubicles, metering cubicles, transformer protection cubicles, coupling cubicles, outgoing cubicles and spare cubicles, if any, must be planned correctly in terms of energy continuity and switching safety. Maintenance area, cable entries and exits, operator access and official authority expectations are considered during switchgear layout planning.

When planning transformer placement, not only the power rating of the equipment but also its cooling structure, ventilation requirements, fire safety, cable connection directions, maintenance access, transportation possibility, safety clearances and operational convenience are evaluated. The selection of oil-type or dry-type transformers should be considered together with the facility location, intended use and safety requirements.

Short-circuit calculation is one of the most important technical studies in a transformer substation project. Short-circuit levels are required for correct selection of circuit breakers, disconnectors, busbars, cables, MV switchgear and protection equipment. Equipment selected without short-circuit calculation may fail to provide adequate safety and operational continuity during a fault.

Voltage drop and cable sizing calculations are important for the healthy operation of loads supplied from the transformer substation. Cable lengths, load currents, route conditions, ambient temperature, installation method and voltage level are evaluated together to determine the appropriate cable size. This study is required for both energy efficiency and operational safety.

Grounding calculation and grounding grid design are among the fundamental parts of transformer substation safety. The grounding system is critical for safely transferring fault currents to earth, limiting step and touch voltages, protecting equipment and ensuring life safety. In transformer substation projects, grounding resistance, grounding conductors, equipotential bonding and site conditions are evaluated together.

When required, load-flow analysis, arc-flash risk assessment, harmonic effects, power quality, compensation and busbar loading conditions can also be evaluated during transformer substation design. These studies help ensure that transformers, MV switchgear, cables and protection equipment are selected according to real operating conditions.

Primary project studies include the selection and layout of the power transformer, MV switchgear, circuit breakers, disconnectors, current transformers, voltage transformers, surge arresters, busbar connections, cable terminations and other main equipment. Correct selection of primary equipment is a fundamental requirement for safe and long-lasting operation of the transformer substation.

Secondary project studies cover protection, control, metering, signaling, communication and monitoring systems. Protection relays, metering circuits, control circuits, alarm signals, auxiliary supply systems, AC/DC panels and, when necessary, SCADA or RTU infrastructure are evaluated within the scope of the secondary project.

Relay coordination and relay selectivity studies are carried out in transformer substation projects to clear faults at the correct point. The goal is to disconnect only the relevant section during a fault, keep healthy sections energized and prevent unnecessary trips. This study is prepared by evaluating short-circuit results, transformer data, circuit breaker characteristics and protection relay curves together.

Auxiliary services should not be overlooked in transformer substation design. Lighting, ventilation, control supplies, battery-rectifier system, auxiliary supply, fire safety, emergency scenarios, labeling and operator usability on site must be considered during the project stage.

TEDAŞ, EDAŞ, TEİAŞ and EMO processes form an important part of transformer substation design studies. Proper preparation of the project file, tracking authority revisions, completing application documents without deficiencies, preparing the official acceptance file and carrying out pre-acceptance technical checks are necessary for the investment process to proceed properly.

Depending on the project scope, high-voltage connection processes, TEİAŞ technical evaluations, connection approval letters, technical approval and acceptance stages may also be handled separately. Ensuring that the documents prepared in these processes match the actual site condition is important for both authority approval and future operational safety.

In transformer substation consultancy, not only project documents but also site conditions, operational safety, authority approval requirements and long-term maintenance needs are evaluated together. This approach helps the investment be managed safely and sustainably not only during the initial installation stage but also throughout the operation period.

A transformer substation project may be required not only for new facility investments but also for capacity increases in existing facilities, transformer capacity changes, MV switchgear renewal, panel revision, generator integration, solar power plant connection, power quality problems or authority approval processes. In existing facilities, the consistency between the actual site condition and existing documents is also checked during project studies.

Transformer substation design service can be applied in different scopes such as industrial facility substation projects, OIZ factory substation revisions, MV switchgear renewal projects, transformer capacity increase project consultancy, solar power plant connected substation projects and technical assessment of existing transformer substations.

During commissioning, it must be verified that the transformer substation project has been correctly implemented on site. The transformer, MV switchgear, protection relay, metering circuits, grounding, continuity, compensation, auxiliary services and other systems deemed necessary are tested and checked. These studies are important for safely energizing the facility and creating reference values for future maintenance and periodic inspection activities.

During the quotation process, facility type, installed power, demand power, transformer capacity, voltage level, number of MV switchgear units, existing single-line diagram, panel structure, machinery list, cable distances, authority approval requirement, site survey, revision scope and commissioning support are evaluated together. This allows us to prepare a phased engineering proposal that reflects the real technical scope of the transformer substation project, rather than only a general price.

Pow-Sys Power Systems approaches transformer substation design not only as a drawing preparation process but as a technical engineering study that considers energy continuity, operational safety, maintenance convenience, official processes and long-term facility requirements together.

For transformer substation projects, transformer substation design, transformer substation consultancy, MV switchgear arrangement, short-circuit calculation, grounding calculation, relay coordination or authority approval processes, you can share your facility information and request a project-specific comprehensive engineering evaluation.