Power SystemsPower Transmission

What is Mobile Substation? Types, Comparisons and Applications

What is a Mobile Substation? Types, Comparisons, and Applications


Mobile substations provide easily relocatable and fast-deployable electricity transformation and distribution capabilities using packaged equipment mounted on movable platforms. They offer flexible solutions for temporary capacity needs and emergency power restoration. Let’s examine what mobile substations are, different types and components, working principles, benefits, limitations, and applications.

What is a Mobile Substation?

A mobile substation is an entirely self-contained package substation built on a movable skid, vehicle, or trailer that can be conveniently transported and quickly set up where needed. It houses all the major substation equipment, like power transformers, switchgear, auxiliary systems, etc., in a compact transportable enclosure.

Need for Mobile Substations

Mobile substations fulfill the needs of:

  • Rapid deployment with minimum site work for temporary capacity
  • Quick electricity restoration during outages and natural disasters
  • Interim transmission and distribution solutions
  • Electrification of remote off-grid locations

Mobile Substation Basics

A mobile substation provides the full functionality of a conventional substation but incorporates transportability through compact modular design and mounting on movable platforms. They range from a few MVA to over 100 MVA ratings.

What is Mobile Substation? Types, Comparisons and Applications
What is a Mobile Substation? Types, Comparisons, and Applications

There are several types of mobile substation platforms used:

Types of Mobile Substations

Trailer Mounted

All equipment, including the transformer, is mounted on a multi-axle heavy-duty trailer for towing by a tractor or truck.

Skid Mounted

Major components are installed on skids, forming interconnected modular assemblies that can be moved using jacks or skidding.

Vehicle Mounted

Light equipment like distributed transformers, switchgear, etc., is mounted on trucks for mobility. But the transformer may be separate.


Components are housed in standardized containers and easily transported intermodally by road, rail, or ship.

Mobile substations incorporate specialized compact equipment:

Components of Mobile Substations


Compact transformers with fast roll-on roll-off features are used. Specialty cooling oils enable space savings.


Minimum space SF6 or vacuum circuit breakers, fused switches, reclosers, etc., are installed in metal-clad enclosures.

Auxiliary Systems

Includes protection relays, metering, battery chargers, ventilation, insulation, lighting, etc., optimized for space and performance.

Housing and Mounting

Robust weather-proof housings, skids, platforms, etc., allow easy vehicular mobility and quick site installation.

The components enable key electrical functionality:

Working Principle of Mobile Substations

Voltage Transformation

The transformer scales transmission level voltages up or down to lower distribution voltages for loads or grid interconnection.

Protection and Control

Switchgear and relays protect downstream circuits and equipment while controls manage breaker operation locally and remotely.

Resistive and Reactive Power

The transformer handles real and reactive load power demands based on rating and grid intertie capabilities.

Cooling and Insulation

Exceptional cooling and insulation systems dissipate heat and ensure insulation strength despite space constraints.

Mobile substations provide valuable advantages:

Advantages of Mobile Substations

Fast Deployment

Minimal site work allows quick transportation and installation where needed – ideal for emergency restoration.

Flexible Siting

Substations can be conveniently located optimally closer to temporary loads owing to easy mobility.

Cost Effectiveness

Mobile substations eliminate the significant civil construction costs associated with fixed conventional substations.

Ease of Relocation

Changing capacity needs can be met by quickly shifting and relocating mobile substations.


Available over various voltages and capacities by selecting optimal transformer, switchgear, etc.

Minimal Site Work

Turnkey delivered units allow quick installation with minimal construction needed.

However, some limitations do exist:

Disadvantages of Mobile Substations

Durability Concerns

Constant relocation and vibration can affect longevity and increase the equipment’s maintenance needs.

Limited Ratings

Mobile designs limit the very high capacity and voltage equipment that can be accommodated.

Monitoring Limitations

Frequent location changes may compromise remote monitoring and control systems.

Typical applications where mobile substations deliver valuable solutions:

Applications of Mobile Substations

Temporary Capacity Expansion

Quickly boost capacity for short-duration projects or event loads without major fixed investment.

Emergency Power Restoration

Rapidly restore electricity supply after grid disruptions caused by weather, faults etc.

Remote Area Electrification

Economical off-grid access for rural villages, mining sites, military camps etc.

Military Sites

Mobile power transformation and distribution at temporary military bases and operations.

Mining Sites

Flexible power supply for mining exploration activities and short-term capacity needs.

Disaster Response

Provide interim power and aid restoration during disasters, emergencies, conflicts, etc., when grids are damaged.

Comparison with Fixed Substations

  • Mobile substations allow faster, cheaper deployment but have lower capacity and longevity than fixed substations.
  • Mobile substations offer flexible siting and relocation possibilities, unlike fixed substation locations.
  • Operating costs are higher for mobile substations, given additional transport needs.
  • Fixed assets like land, buildings, and civil structures are avoided with mobile substations.

Challenges and Limitations

Regulatory Compliance: Mobile substations must comply with local regulations, which can vary widely.

Environmental Considerations: The environmental impact of mobile substations, including noise and emissions, must be addressed.

Maintenance and Training: Proper maintenance and operator training are crucial for the reliable operation of mobile substations.

Case Studies

Mobile Substations in Disaster Recovery: Examples of how mobile substations have been instrumental in disaster-stricken areas.

Mobile Substations in Remote Areas: Instances where mobile substations have provided power in remote and off-grid locations.

Future Trends

Smart Mobile Substations: Integration of advanced monitoring and communication technologies for enhanced control and data analysis.

Renewable Energy Integration: Mobile substations are adapting to support the integration of renewable energy sources into the grid.


Mobile substations are dynamic solutions for today’s ever-evolving energy landscape. Their mobility, flexibility, and rapid deployment capabilities make them indispensable in emergencies, remote locations, and various industries. As technology continues to advance, mobile substations are set to play an even more significant role in ensuring a reliable and efficient power supply for all.


Mobile substations address the niche needs of rapid, temporary transformation and electricity distribution. They allow customizable capacity to be relocated through compact, vehicular-mounted designs. While ratings and durability are constrained relative to fixed substations, mobile substations enable versatility and responsiveness for varied applications like emergency restoration.


  1. What is the key benefit of using a mobile substation?

Mobile substations allow rapid deployment and flexible relocation of electricity transformation and distribution equipment where needed.

  1. What major components do mobile substations contain?

They contain compact modular assemblies of a transformer, switchgear, auxiliary systems, protection, controls, etc., mounted on movable platforms.

  1. What types of mobile substation platforms are used?

Typical platforms include trailer mounted, skid mounted, truck mounted, and containerized mobile substation enclosures.

  1. What are some typical applications of mobile substations?

Applications include temporary capacity expansion, emergency restoration, remote electrification, disaster response, military sites, etc., needing mobility.

  1. How does a mobile substation transform voltage levels?

It uses a transformer to convert between higher transmission voltages and lower distribution voltages to integrate loads or grids.

  1. What are the disadvantages of mobile substations?

Limitations include lower durability from vibration, limited capacity and voltage ratings, higher operating costs, and monitoring challenges.

  1. How does a mobile substation provide switchgear needs?

It utilizes compact minimum space switchgear like SF6 or vacuum circuit breakers, reclosers, fused switches, etc., in metal-clad enclosures.

  1. How does modularity help with mobile substations?

Pre-assembled modular skids allow the interconnecting of various components into a complete substation assembly, facilitating mobility.

  1. How do mobile substations aid disaster response?

They allow rapidly deploying interim power transformation and distribution at affected sites to help restore supply when permanent substations are damaged.

  1. How are mobile substations transported to sites?

Modes include tractor-trailers, skid steerable platforms, all-terrain vehicles, and containerization enabling flexibility.

Engr. Muhammad Ali Raza

Hello, I'm Engr. Ali Raza, an Electrical Engineering Professional with a passion for innovation and a commitment to excellence. I completed my electrical engineering degree in 2017 and have since been actively engaged in the field, where I've had the opportunity to apply my knowledge and skills to real-world projects. Over the years, I've gained valuable experience in Engineering field, allowing me to contribute effectively to the development and implementation of electrical systems and solutions. I thrive in dynamic and challenging environments, constantly seeking opportunities to expand my expertise and make a meaningful impact in the world of Electrical Engineering.

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