Power Distribution Basics & Selection Guides

From the grid to the load: how the equipment works together

This simplified path shows how switchgear, transformers and low-voltage distribution connect the medium-voltage network to local loads.

Medium-Voltage Distribution Network
01

MV Switchgear / Ring Main Unit

Connects the incoming supply, switches feeders, applies protection and isolates faulted sections.

02

Transformer

Steps voltage down for local distribution; in generation and renewable projects, it may also perform the step-up duty.

03

LV Switchgear & Distribution

Receives the transformed supply, protects outgoing circuits and distributes power to local loads.

Industrial, Commercial & Infrastructure Loads

Start Here: Equipment Basics

New to power distribution? Begin with the complete system map, then open the equipment guide you need for construction, operating principles, model differences and service life.

01Power Distribution Equipment for BeginnersFollow electricity from the grid to the load and separate voltage, current, capacity, power and energy. 02How Distribution Transformers WorkSee the core, windings, insulation and cooling path, then understand why ratings and constructions differ. 03How Switchgear and RMUs WorkSeparate the jobs of breakers, switches, fuses, busbars and relays, and see where an RMU fits. 04Inside a Compact SubstationTrace power through the MV, transformer and LV sections and learn how one package becomes many configurations.

Choose a Selection Guide

Choose the equipment family first, then confirm its ratings, construction and project-specific configuration.

01

Compact Substation Selection Guide

Define the incoming system, transformer duty and outgoing distribution before comparing prefabricated and pad-mounted configurations.

  • System voltage, total load and outgoing circuits
  • MV unit, transformer and LV unit arrangement
  • Enclosure, ventilation, foundation and cable entry
Open Selection Guide
02

Transformer Selection Guide

Choose the transformer by its system duty, then compare construction, voltage class and application requirements.

  • HV and LV voltage, capacity and frequency
  • Oil-immersed or dry-type construction
  • Vector group, taps, impedance and accessories
Open Selection Guide
03

Switchgear & RMU Selection Guide

Start with the switching and protection duty, then confirm the rated current, short-circuit level, feeder arrangement and operating method.

  • Rated voltage, current, fault level and circuits
  • Fixed, withdrawable, gas or solid-insulated construction
  • Protection, interlocking, operation and maintenance
Open Selection Guide

Transformer Knowledge Guides

Use these guides for transformer sizing, vector groups, factory tests, pre-energization checks and lifecycle-cost comparison.

01How to Size a Distribution TransformerBuild a defensible kVA estimate from connected load, demand, motor starting and future allowance. 02Transformer Vector Groups ExplainedRead clock notation and understand why phase displacement, neutral and system compatibility matter. 03Transformer FAT and Test ReportsSeparate routine, type and special tests, then review the records supplied for the actual unit. 04Pre-Energization Inspection ChecklistCheck receipt, storage, installation, earthing, insulation and protection before first energization. 05Transformer Losses and Lifecycle CostCompare purchase price with no-load loss, load loss, duty cycle and expected operating years.

Project Information Checklist

Send any available project information; we will identify any additional technical details needed to review the configuration.

Upload Project Requirements ›
Single-line diagramExisting SLD or a simple system sketch.
Application and system roleUtility, industrial, commercial or renewable-energy duty.
Voltage and frequencyIncoming, outgoing and local system frequency.
Capacity or connected loadRequired rating, load schedule or feeder demand.
Destination and standardsCountry, applicable specification and approval needs.
Installation environmentIndoor or outdoor, temperature, altitude and protection needs.
Required project documentsDrawings, datasheets, test records, FAT scope and handover files.