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A Modular Concept for HV Solar Substations

EPEC partner Equisales Associates has harnessed their vast experience and engineering horsepower to develop a modular offering for HV solar collector substations.  These skid based systems are pre-engineered, packaged and delivered to site for quick installation.  With Equisales technology a substation “project” can be turned into a “product.”  

The Equisales modular system offers these advantages:


  • Pre-engineered, eliminating construction site risk

  • Significantly improve delivery times, turnkey substations in 24 weeks!

  • Flexible, add skids to match your substation MVA requirements

  • Cost effective, pre-engineered means big savings

  • Complete design build services, turnkey

  • Power transformer supply & service (18 week L/T)

Modular Substation Layout

Modular Building Blocks - Skid Based System

30 kV - 72.5 kV Skid

Electrical Specification

Voltage:                 30 kV – 72.5 kV

Current:                 2000A

Control Voltage:    125VDC

CT:                        9 taps

CT Range:            300:5 – 2000:5

CT:                        5P20, 0.2

CVT:                      3P, 0.2

Breaker SCC:        40kA

BIL:                        325 kV


Mechanical Specification

  • Includes galvanized steel base & structure, bolts

  • Assembled dimensions: 27’x15’x22’

  • Weight: 24,000 lbs

  • Estimated 1 week site assembly time

One Line Representation of Skid

  • SF6 breaker, CT, CVT, disconnect switch, ground blade, take off tower, insulators, ground cable, conductor, connections and jumpers all included in kit

  • Containerized transportation

Overhead View (showing transformer)

Modular Building Blocks - MV / LV Control House

Modular Houses for Delivery

Base System Includes:

  • 480v/220v/120v Distribution

  • 125VDC distribution (Breakers and skids)

  • PLC/P&C Panels/SCADA

  • Trailer or non trailer options

  • Aux transformer with fused disconnect

  • Operator Desk/Work Station, Fire detection

  • Single or redundant HVAC

Modular House Detail

The Control House Module is provided to house the required 125VDC battery system sand all required protection and control systems. Battery system includes:

  • (1) 100AH rack mounted battery system for emergency operation of the skid modules.

  • DC distribution panel with ten (10) breakers.  

The protection and control system will include (but not limited to in the final design) the following:

  • High voltage Line Protection Panel

  • 34.5kv Collector bus and incoming skid protection

  • Differential transformer protection

  • Metering as required in specification

  • SCADA Rack (RTAC Based for Substation Devices)

  • Communications Rack

  • Additional operator space

The control house is provisioned with the shown stairs and platforms, support legs, and fire detection system.  Two entry/exit doors are provided for operator safety.   

Trailer Mounted Options Available

Modular Building Blocks - HV Power Transformers

HV Transformers for Solar – 20 Week Delivery!

Equisales offers customized high-voltage transformers designed for specially for solar substations. Typical specs include:

  • ANSI Codes and Standards

  • 10 to 300 MVA

  •  34.5kV LV, 69-230kV HV

  •  DETC +-5% +-2 steps on the High Voltage side

  •  Appropriate Vector Group as required (i.e Ynyn0+d)

  •  Roof Mounted HV and LV bushings

  •  Conservator Design

  •  Standard ANSI Impedance based on BIL

  •  2CT Per Bushing 1 on neutral

  •  Standard gauges and instrumentation package

We Test & Service What We Sell

Comprehensive tests ensure the safe and reliable operation of high-voltage equipment. Our field technicians and certified quality control experts are available to complete critical assessments during the final phase of construction and installation.

Setting HV Power Transformer

Vacuum filling using dielectric oil or gas are essential for the proper operation of high-voltage equipment and energy facilities. Our engineering teams and field technicians perform vacuum filling for clients who require equipment and services for high-voltage substations and fast-track power plants. We complete vacuum filling following repairs, routine maintenance and the installation of new equipment.

Standardized training programs and best practices mean that repairs, maintenance and emergency services are completed with the same quality no matter which team is in the field. If an SF6 circuit breaker fails or a transformer needs a major upgrade, our repair and manufacturing experts can complete the job quickly and professionally. When downtime means production setbacks or service interruptions, we offer emergency rentals and replacements that will protect your power supply and profits.

Putting it all Together - EPC - Design / Build Turnkey Substations

Power Plant / Substation Construction Site

(E) EngineeringInterconnect Studies, Short Circuit Studies, Substation Layout, Single Line, Three Line, Relay Protection and Control, Ground Grid Design, Utility Tie Interface

(P) Procurement - Transformers, Breakers, CVTs, CTs, Disconnect Switches, MV / LV Control House, Aux Transformers, 18 Weeks ARO

(C) Construction - Full turnkey installation of supplied equipment from anchor bolts up (we can do civils too if asked) 

Equipment / Inventory / Services

  • 3 Self contained vacuum dehydrator Rigs- 40’ ISO containers for ease in shipping

  • Full Turnkey Services for Transformer and HV installation

  • On site Transformer testing

  • Disposal of failed units

  • Transportation Services

  • Extensive Inventory of new and used Equipment for fast recovery of Forced Outages

  • On- Site Transformer Repair capabilities

HV Transformer Service

Putting it all Together - Turnkey Solar Collector Substations

Example Solar Substation

Typical Modules Required for an 80MW Solar Collector Substation

  • 4x 34.5kV skid mounted feeders

  • 1x 34.5kV Collector bus with switch PT & Aux Transformer feed

  • 1x 34.5kV outgoing switch

  • 1x GSU 34.5kV to 230kV Ynyn0+d.  88MVA top rated

  • 1x 230kV skid mounted Substation

  • 1x HVAC control house with P&C system and 125VDC system included

  • Conductor, control wire and cable trench

Division of Responsibility - Turnkey Substation

Download a FREE Modular Substation Configurator

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