MTL-Series Unit Substation Switchgear

Unit Substations with Primary Voltage of 2.4kV-38kV, Transformers kVA: 500-20,000 kVA, & Secondary Voltage: 208V-15kV

APT MTL-Series Secondary Skid-Mounted Unit Substation Switchgear consists of Low & Medium Voltage Switchgear with a power transformer. Moreover, these three units work together to bring service power to the largest facilities. Our MTL-Series certainly offers versatile substations with several configurations.

General Features

Built to IEEE Std C37.121-2012: IEEE Guide for Switchgear – Unit Substation – Requirements
Frequency: 60Hz or 50Hz
Silver plated copper bus
Listed low voltage bus ampacity up to 4000A
- Unlisted options built to UL standards available upon request for main buses larger than 4000A
Busbar connections with NEMA standard hole pattern
Front or Rear Bus Access for either top or bottom cable entry
Low Voltage Power, Insulated Case Circuit Breakers, or Molded Case Circuit Breakers:
- See page 9 of APT MTL-Series Unit Substation Switchgear Brochure for more information
Installation Location & Enclosure:
- NEMA 1 for Indoor Installation
- NEMA 3R for Outdoor Installation
- Manufactured from Carbon Steel, Aluminum or Stainless Steel (304 or 316)
- Powder coated ANSI 61 Gray
- NEMA 1 Lockable T-handles
- Internal Climate Control (requires 120VAC)
  - Anti-condensation Heater w/Thermostat
- NEMA 3R Stainless Steel hardware & pad lockable handle
- Optional Power System Mimic Bus

Medium Voltage Unit Sustation Switchgear Features

Ratings: 2.4kV – 38kV, 3Ø
Main Protection Disconnect Sections Options:
- IEEE Std C37.20.2 – Metal-clad Drawout Vacuum Circuit Breaker
- IEEE Std C37.20.3 – Metal-enclosed Fused Air Insulated Loadbreak Interrupter Switch (LIS)
- Metal-enclosed Unfused Air Insulated Switch with Fixed or Roll Out Vacuum Circuit Breaker
- Metal-enclosed Drawout Vacuum Circuit Breaker
- IEEE 386 – Loadbreak or Deadbreak Bushings with Optional Grounding
- IEEE Std C37.23 – Metal-enclosed Bus Stabs with NEMA Standard 2-hole pattern directly to the transformer or incoming line pull section

Power Transformers

High Voltage Side

Aluminum windings
2.4kV – 34,500 V Delta or Wye connected
BIL up to 200 kV
Tap changer: ± 2, 2.5%
Live front
Radial feed
Optional Bushing wells

Common Features

Up to 4MVA Transformers
- Dry-Type
- Cast-Coil
- Oil-Filled
Built to all applicable IEEE C57.12.34
Cooling Class: ONAN
Pad Mount, Step Down
Ratings:
- 500kVA – 4,000 kVA
- Frequency: 60Hz
- Impedance: 5.75%
  ± 7.5%
- Temperature Rise: 149°F
Dead Front or Loop Feed Option
Enclosure:
- Indoor NEMA 1 or Outdoor NEMA 3R
- Mild steel tank & cabinet
- Powder Paint System; Color: ANSI 70 or Green Munsell 7GY 3.29/1.5
- Weights: 7000-17500 lbs.

Low Voltage Side

Aluminum windings
Single Low Voltage Winding
208V – 120 V Delta or Grounded Wye Connected
BIL up to 10kV
Epoxy 2-piece bushings with 4-holes blade

Low Voltage Unit Sustation Switchgear Features

Transfer & Backup Options

Automatic Source Transfer for Double Ended Substations:
- Add secondary paths to provide power to your feeders via a double ended substation
  - As a result, this enables the ability to feed loads from two different utility or generator sources automatically
- Automatic standby with Open or Closed Transition return operation
Backup Portable Substations for Integrated Generator/Load Bank Quick Connection
- Adds the ability to connect temporary power to your unit substation/unit substation switchgear to provide power to your feeders
  - This is done through integrated Generator Quick Connection
  - Backup your ability to feed loads manually via temporary generator connection

Ratings: 208V – 690V, 3Ø
ANSI/UL 891 Listed & Labeled Low Voltage Main Protection and Feeder Sections Options:
- UL 489 Insulated Case & Molded Case Circuit Breakers
- Built to IEEE Std C37.20.1 with UL 1066 Listed Low Voltage Power Circuit Breakers
Interrupting Rating: 18kA – 200kA @ 480VAC
Circuit Breaker position Aux Contacts (“a” and “b”)
Your Choice of Circuit Breakers:
- Low Voltage Power Circuit Breakers (LVPCBs)/Insulated Case Circuit Breakers (ICCBs):
  - Available from 100A up to 6000A
  - LVPCBs UL^® 1066 Listed
  - ICCBs UL^® 489 Listed
  - See page 9 for table of available circuit breaker frame ratings
  - Electrically or Manually Operated
  - 100% Rated
  - Fixed Mounted or Drawout
  - Electronic Trip Units – LI, LSI, LSIG
- Molded Case Circuit Breakers:
  - UL^® 489 Listed
  - Available up to 3000A
  - Manually Operated
  - Electrically Operated with Motor Operator Add-on
  - Standard or 100% Rated
  - Fixed Mounted
  - Thermal Magnetic or Electronic Trip Units – LI, LSI, LSIG

Motor Starting, Protection, & Control

Add Motor Starting Capability to your Secondary Unit Substation Switchgear
Single Phase and Three Phase (115V – 575V) motor controls
0.5HP – 400HP drives in a single standard section
Over 400HP through 800HP drives can be housed in larger custom sized sections
Hand-Off-Auto control switches and activity indicating lights gives users the ability to control motors from the control panel
Terminal blocks as needed for customer field connections
Able to house:
- Variable Frequency Drives
- Motor SoftStarters
- Manual Starters
- Motor Controller Contactors
- Overload Relays
- Full Voltage Non-Reversing or Reversing Starters
Air Flow cutouts ensure proper cooling for the number of devices