What Is a 315 kVA Mini Substation?
A 315 kVA mini substation (also known as compact substation or package substation) is a prefabricated power distribution unit that integrates a transformer, high-voltage switchgear, low-voltage switchgear, protection devices, and internal wiring into a single outdoor enclosure. It is designed to step down medium voltage (typically 11kV or 33kV) to a low-voltage level (400V) suitable for local distribution.
These units are widely used in urban networks, industrial zones, commercial areas, e temporary construction projects, where space and installation time are limited.
Key Components of 315 kVA Compact Substation
A typical mini substation includes:
- HV Section: Load break switch (LBS) or vacuum circuit breaker (VCB)
- Power Transformer: 315 kVA oil-immersed or dry-type transformer
- LV Section: MCCB, MCB, or ACB for outgoing distribution
- Enclosure: Galvanized sheet steel, aluminum, or stainless steel with IP54–IP65 protection
- Cooling: Natural air cooling (AN), or oil cooling (ONAN)
- Protection: Earth fault protection, surge arresters, overcurrent protection
- Metering and Relays (optional): For remote monitoring or SCADA integration
Technical Specification Table
| Parametro | Value |
|---|---|
| Capacità nominale | 315 kVA |
| Input Voltage (HV) | 11 kV / 22 kV / 33 kV (customizable) |
| Output Voltage (LV) | 400V / 230V (3 phase + N) |
| Cooling Type | ONAN (oil-immersed) / AN (dry-type) |
| Frequency | 50Hz / 60Hz |
| Impedance | ~4% (can vary) |
| Enclosure Type | Outdoor IP54–IP65, modular metal container |
| Tipo di installazione | Pad mounted / Pole mounted |
| Protection Devices | Fuses, MCCB, Earth Fault Relay, etc. |
| Standard di conformità | IEC 62271, IEC 60076, ISO 9001 |
Applications of 315 kVA Mini Substation
- Urban residential areas
- Commercial buildings and malls
- Industrial workshops and processing units
- Construction and mining sites
- Agricultural pumping & irrigation systems
- Remote power distribution (rural electrification)
315 kVA Mini Substation Price Overview
Il price of a 315 kVA mini substation can vary widely depending on configuration, brand, and additional features. Below are the key influencing factors:
Price Factors
- Transformer Type: Oil-immersed is cheaper than dry-type.
- Voltage Class: 11kV units are typically less expensive than 33kV models.
- Enclosure Material: Galvanized steel is more affordable; stainless steel costs more.
- Livello di protezione: Higher IP rating and smart protection relays increase the price.
- Switchgear Configuration: Manual LBS vs. motorized VCB affects the cost.
- Customization: SCADA, remote metering, and surge protection raise the price.
- Quantity and Shipping: Bulk orders and shipping distance matter.
Estimated Price Range
| Type | Approximate Price (USD) |
|---|---|
| 11kV Oil-immersed | $4,000 – $5,500 |
| 11kV Dry-type | $5,500 – $7,500 |
| 33kV Oil-immersed | $6,000 – $8,000 |
| 33kV Dry-type (IP65 rated) | $8,000 – $10,000 |
📌 Note: Prices are indicative and vary by manufacturer, location, and features.
Installation & Maintenance
- Plug & Play: Minimal civil work required; installation in <1 day.
- Low Maintenance: Periodic inspection and transformer oil tests (for oil type).
- Safety: Built-in earthing and overload protection.
Advantages at a Glance
- Quick deployment and commissioning
- Reduced land usage
- All-in-one compact design
- Safe and weatherproof enclosure
- Easy to relocate (for mobile substations)
Frequently Asked Questions (FAQs)
Q1: Is 315 kVA sufficient for residential buildings?
Yes. A 315 kVA transformer can support medium-sized residential communities or commercial spaces.
Q2: Can I choose between dry-type and oil-type transformer in mini substations?
Absolutely. Most suppliers offer both configurations depending on your environmental and fire safety needs.
Q3: Do I need a separate foundation for mini substations?
Usually, a simple concrete base or steel skid is sufficient. No large civil work required.