The Foundation Layer

Series 70: eSTS

1600 A - 4000 A Static Transfer Switch

Product Brochure
Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

eSTS Protects The Power For Critical Operations

Even Entire Buildings
eSTS Automatically Transfers Between Two or Three* Power Sources
LayerZero Power Systems designs and manufactures the world’s most reliable static transfer switch. The Series 70 eSTS is

a solid-state transfer switch that automatically or manually provides solid state transfers between two in-phase AC sources

in a quarter cycle. The eSTS performs open-transition transfer in such a manner that the connected load disruption

is minimized without ever cross-connecting the power sources. One power source is selected to be the preferred

source. If the preferred source fails the load is automatically and seamlessly connected to the alternate source by

means of an open-transition static transfer. For emergency transfers between asynchronous sources, dynamically

phase compensated transfers minimize saturation of downstream transformers in 3-phase, 3-wire eSTS.

*Optional

2 © Copyright 2017 LayerZero Power Systems, Inc.

Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

Standard Features

LayerZero’s eSTS Is Equipped Fully-Loaded

Reliability

;; Optional Triple Modular Redundancy: TMR Contains Fully-Independent Control Paths With No Single Point-Of-Failure
;; Safe Bypass Procedure: Mechanical Bypass Interlock Eliminates Human Error When Performing Bypass Procedures
;; Voice Guided Bypass: Step-By-Step Instructions With Audio and Video Guidance To Assist Operators Through Bypass
;; Epoxy Coated Buswork: Maximizes Reliability By Eliminating The Possibility of Bus-To-Bus Faults
;; Silver Plated Terminals: Silver Has Excellent Conductivity To Provide Superior Electrical Performance and Reliability
;; Maintenance-Free Joints: Brazed Joints Are Permanent And Maintenance-Free, Maximizing Product Life
;; Machined Hardware: Machined Cap Screws and Engineered Disc Springs Maintain Constant Torque Throughout Product Life
;; Screw Thread Inserts: Prevents Screws From Loosening Under Vibration For Long-Term Reliability
;; Optical Fiber Based Controls: Eliminates Noise and Interference While Isolating Components from High Voltage
;; Serialized Critical Board Tracking: Critical Boards Are Serialized And Cataloged in an Active Database For Traceability

Safety

;; InSight™ IR Portholes: Bolted Connections & Critical Boards Can Be IR Scanned With the Dead-Front Doors Closed
;; Sectionalized Components: Isolated Sections That Can Be Safely De-Energized For Performing Maintenance
;; Polycarbonate Windows: Allows Critical Board LEDs To Be Viewed With The Dead-Front Door Closed
;; Dead Front Hinged Doors: Barrier To Provide A Safe Working Area With No Exposed Live Parts

Connectivity

;; Ethernet Connectivity: Secure VPN Router Connects To Network For Advanced Remote Monitoring Capabilities
;; Modbus/TCP: Open Connectivity to Existing Monitoring Systems Without Proprietary Limitations
;; NTP Time Clock Synchronization: Facilitates Timeline-Based Logging For Post-Event Reconstruction
;; SNMP Connectivity: Permits Remote Management Via Simple Network Management Protocol

;; Real-Time Waveform Capture: Automatically Captures A Picture Of The Power Three-Cycles Before and After Every Event
;; Local Touch-Screen Interface: Password-Protected Color Touch-Screen GUI For Local STS Setup/Operation/Administration
;; Black-Box Forensics: eSTS Captures and Records All Events To Provide Vital Information In Root-Cause Analysis
;; Waveforms Automatically Emailed: Capability to Send Waveform Captures To Designated Individuals For Every Transfer

3 © Copyright 2017 LayerZero Power Systems, Inc.

Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

All LayerZero Power Systems products have on-board power quality analyzers that break down power sources into samples. If the
power quality goes out of specification on a source, eSTS will transfer to the alternate source, automatically generating waveform
captures and ITIC curves of the event. This data is remotely accessible by connecting to the unit via web browser.

In the test below, the STS was connected to two sources 150 degrees out-of-phase. Source 2 breaker was opened, causing the
STS to perform an automatic transfer to the primary source. A delayed transfer occurred, causing events on Phases A, B, and C,
automatically generating ITIC plots. Unlike waveform captures, ITIC plots are easy-to-read, and do not require expert analysis to
understand.

Example Waveform Capture of Source 2 to Source 1 Transfer Event,

150 Degrees Out-of-Phase

Primary Source Volts

Alternate Source Volts

Voltage Disturbance at the Load

Output Volts

Primary Source Amps

Alternate Source Amps

Output current after transfer. There is
no transformer saturating current.

Output Amps

Source 2 to Source 1 Transfer Event, 150 Degrees Out-of-Phase - WFC & ITIC Plot
Dynamic Transfer was enabled during these tests in order to mitigate transformer inrush while completing the transfer
within the boundaries set by the Information Technology Industry Council (ITIC).
Phases A, B, and C Triggered Events, and Generated an ITIC Plot

The events are all within the boundaries of the ITIC curve

The ability to keep the transfers within the ITIC limits was verified through the Voltage Disturbance
Analysis Tool (VDAT) plot shown above in the captured waveform.

4 © Copyright 2017 LayerZero Power Systems, Inc.

Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

Equipment Layout

Controls Section Contains:

Power electronics
• SCRs (Silicon Control Rectifier) in
Convection Cooled Heat Sinks
Control Electronics
• System Control & Data Acqusition
Boards
• SCR Gate Drives
• Redundant Power Supply System
• I/O system; VPN Router

Heat SInk Section Contains:

Heat SInks

CB Section Contains:
Input isolation switches
Bypass isolation Switches
Output isolation switches
Source connection terminals
Load connection terminals

1 2
15” Color Touch Screen (Standard)

3
1. Stereo Speakers for Guided Bypass Prompts 4 5

2. Output On Light (Remains Lit in Bypass Isolate Mode)

6
3. Alarm & Bypass Indicator

4. SCB Status Indicator

5. Logged In User

6. Navigation Menu
20
7 8
7. Customer & Project Information

8. Date & Time

5 © Copyright 2017 LayerZero Power Systems, Inc.

Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

Reliability Overview

LayerZero eSTS Reliability Overview

The LayerZero eSTS Provides Many Dimensions of Reliability:

• Control System Reliability

• SMR (Single Module Redundancy, Standard)

• TMR (Triple Modular Redundancy, Optional)

• Control Power Supply Reliability

• Signal Reliability

• Operator Procedural Reliability

Single Module Redundancy (SMR) Reliability (Standard)

Fiber Optics

Single Module Redundancy is a cost-effective topology that provides Gate Drive 1

Source 1 A

redundant power paths to mission-critical equipment. In SMR

systems, sources each have built-in triple redundancy of processors. Gate Drive 2
Source 1 B

Gate Drive 3

In addition, every phase is controlled with a separate gate drive Source 1

Control
Source 1 C

board. Source 2
Control

Gate Drive 4
SCB 1 Source 2 A

LayerZero Single Modular Redundant topology is unique that it the WAN Port

Gate Drive 5
Source 2 B
system is fail-safe, maintaining full switching functionality even if a

critical board were to fail. Gate Drive 6

Source 2 C

6 © Copyright 2017 LayerZero Power Systems, Inc.

Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

Reliability Features: Triple Modular Redundancy (TMR) *Optional

Triple Modular Redundancy (TMR) Reliability (Optional)

LayerZero TMR has all the redundancy of SMR, plus each STS has three
independent sets of analog and digital data acquisition and control
systems. There is no direct communication between the three systems.
The three systems do not even share a common system clock.

Each control system acquires voltage and current data independently

Each control system determines whether a source is good/bad
independently
Upon loss of a source, each control system makes decisions to transfer
independently

Even if an entire control path or its subcomponent were to fail; and

then if the active power source were to fail, the STS is able to complete
its mission of transferring to the alternate source.

Triple Modular Redundancy, a proper noun, is a based on proven

statistics and stringent mathematics. There are similar sounding
terms like, tri- or triple- redundant, used in industry to describe other
STS products – but they simply do not yield the same, high level of
reliability.

Fiber Optics

Source 1
Control
Gate Drive 1
Source 1 A

Source 2
Control

Gate Drive 2
SCB 2 Source 1 B
(TMR)

Gate Drive 3
Source 1 C
Source 1
Control

Source 2
Control

Gate Drive 4
SCB 1 Source 2 A

WAN
Port Gate Drive 5
Source 2 B
Source 1
Control

Source 2 Gate Drive 6

Control
Source 2 C

SCB 3
(TMR)

7 © Copyright 2017 LayerZero Power Systems, Inc.

Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

Reliability Features: Single Module Redundant (SMR) Redundancy

eSTS SMR Triple Redundant Power Supply Architecture

Divided into four (4) logical failure groups:

Source 1 Source 2
• System controls ABC ABC

• Source 1 gate drives PS 1

Peripherals
PS 3
• Source 2 gate drives S1 A-B S2 B-C

• Peripherals.
System Controls
The three (3) available source of power from which to supply control PS 4 PS 6
power to each failure group are: S1 B-C
SCB 1 SCB 2
TMR Only
SCB 3
TMR Only
S2 A-C

• Source 1
Gate Drives,
• Source 2 PS 7
Source 1
PS 9
• STS Output. S1 A-C
GD 1 GD 3 GD 5
S2 A-B

LayerZero’s STS design incorporates twelve (12) power supplies (3

Gate Drives,
power sources x 4 failure groups.) The resultant control power topology Source 2
PS 10 PS 12
utilizes all possible power paths to the four logical STS failure groups; S1 A-B
GD 2 GD 4 GD 6
S2 B-C

and is the most comprehensive and redundant power supply system in

existence.
Peripherals System Controls Gate Drives S1 Gate Drives S2

PS 2 PS 5 PS 8 PS 11
Out A-C Out A-B Out B-C Out A-C

A Output
B Bus
C

eSTS SMR Triple Redundant Processors

• Separate/independent processors for Source 1, Source 2 and

Output power quality analysis S1 S2 Output

• If Source 1 processor malfunctions then system is able to be

commanded to transfer to Source 2; & vice versa.
Source 1 Transfer Control Source 2 Transfer Control

• If main control system fails then STS continues to conduct power to

A B C A B C
the load from the existing source of power. (However STS is unable
to transfer to the other source)

• Each phase of each source is controlled with a separate gate drive Gate Gate Gate Gate Gate Gate
Drive 1 Drive 2 Drive 3 Drive 4 Drive 5 Drive 6
circuit board.

8 © Copyright 2017 LayerZero Power Systems, Inc.

Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

Reliability Features

Safe Bypass Procedure

In order to minimize the possibility of operator error during equipment

bypass operations, LayerZero provides:

1. Interlocked breakers
2. Mechanisms to ensure that a source cannot be bypassed without
the STS on the correct source.
3. Safeguards to make certain that sources cannot be connected to
each other inadvertently.
4. A voice-prompted bypass procedure that guides the operator
through the sequence.
5. A step-wise pictorial & video presentation is provided on the
touch-screen display during bypass.

Voice Guided Bypass

Operator error during maintenance bypass has been known to be

a reliability hazard. To help prevent operators from completing the
bypass procedure out-of-sequence, our product features a voice
prompted bypass procedure. This instructs the operator in a step-
by-step course of action of the process, with only one operation
per screen. Visual and audio cues provide clear instructions on the
bypassing sequence, reducing the probability of operator error.

Epoxy Coated Buswork/Maintenance Free Joints

Our usage of epoxy coated buswork helps ensure safety, and

makes the system inherently more reliable by eliminating the
possibility of bus-to-bus faults. Bus joints are permanently brazed
and maintenance-free.

Silver Plating

LayerZero utilizes silver plating on all bus joints and terminals

to be able to provide the highest performance. Silver has high
conductivity and low resistance - which makes for a great contact.

9 © Copyright 2017 LayerZero Power Systems, Inc.

Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

Reliability Features

Machined Hardware

Our bolted connections utilize machined cap screws and engineered

disc springs. The result is a flat pressure vs deflection profile to ensure
that all bolted connections maintain constant torque through the life
of the product.

These technologies have been well tested in disparate environments of

wide temperature ranges to help ensure that, once connections have
been tightened, they stay that way.

Fiber Optic Controls Increase System Reliability

Fiber optic based controls eliminate noise and interference, while

isolating components from high voltage.

Optical fiber allows service to be reliably connected, while protecting

the equipment.

In LayerZero’s eSTS design, the gate drives (at Power Circuit Voltage)
receive control signals via optical fibers.

Serialized Critical Board Tracking

We serialize and track all critical boards and maintain this information
in an active, dynamic database.

10 © Copyright 2017 LayerZero Power Systems, Inc.

10
Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

Ease of Maintenance

InSight™ IR Portholes Permit Scanning of Bolted

Connections with Dead-Front Doors Closed

Strategically positioned IR-scan portholes to enable safe thermal

scanning of all bolted connections with the deadfront closed, without

exposing the operator to power circuit voltage. Thermal scans on

1600 A - 4000 A eSTS are completed from the rear of units.

The IR window swivels upward and unlocks with key-hole access to

reveal a mesh, allowing the operator to point-and-shoot thermal

cameras to obtain readings.

1
Source 1 Source 2
1

2 CB101 CB102

CB201 CB202

CB301 CB302

Load

2 2

IR Portholes in eSTS

11 © Copyright 2017 LayerZero Power Systems, Inc.

Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

Ease of Maintenance/Connectivity Options

Sectionalized Components Help Maximize Operator Safety

Operators are well-protected from exposed connections. Normal

operator sections (breakers/switches) are physically separated

from the power electronics and control electronics sections, so that

maintenance on a section can be safely performed. If maintenance is

required on a particular section, power can be bypassed to another

section to allow for safe repairs to be made. All connections are

optically isolated to minimize risk.

eSTS Connectivity Options Series 70: eSTS

Standard
Dry Contacts
Ethernet

http:// through a Simple Network Waveforms Network Time Protocol

Modbus/TCP Management Protocol • Summary Alarm
standard web browser Automa�cally Emailed (NTP) Compliant
(SNMP) • On Source 1
For Clock Synchroniza�on
• On Source 2
• Source 1 Available
• Source 2 Available

• Meters • Meters
• Alarms • Alarms
• Waveforms
• History/Event Log
• Diagnos�cs

12 © Copyright 2017 LayerZero Power Systems, Inc.

 Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

Power Quality Monitoring

The Series 70: eSTS is equipped with Zen SSQM (Static

Switch Quality Monitoring), an all encompassing
monitoring system with local and remote
communications options.

From basic monitoring & alarm reporting, to advanced

power quality monitoring functionality, Zen SSQM
provides a wide-range of options to help you be aware,
be vigilant, be proactive in your quest to create a safe,
stable and reliable operation.
Product Name: Series 70 ePODs: Type-P Capture Reason: SQ Xfer 0-1 Phase A
Phase B
Unit Name: 500 + 1000 turn CTs Captured By: scb122
Phase C
Serial #: 10028-34 Capture Time: 01-04-2016 6:53:08 PM Phase N
Microticks: 1449941 Phase G
Source 1 Volts L-L

1000
800

Zen SSQM Provides Answers

600
400
V 200
o
l 0
t
s
Zen SSQM provides timestamped pictures of waveforms before and after events, providing information that
-200

enables facilities to go back in time to methodically identify and correct the root causes of events. Zen actively
-400
-600
captures power quality information at the STS, PDU, and RPP - permitting thorough post-event analysis.
-800
-1000

Milliseconds
Source 2 Volts L-L
3 Electrical Cycles 3 Electrical Cycles
1000
800
600
400
V 200
o
l 0
t
s -200
-400
-600
-800
-1000
Phase A Waveform Capture of Current in a Source Transfer
Milliseconds
Phase B
Load Volts L-L
Trigger Event
Phase C
1000
13
800 © Copyright 2017 LayerZero Power Systems, Inc.
600
400
V 200
o
Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

Power Quality Monitoring

A Current Metering Point

V Voltage Metering Point

PQ Power Quality Metering Point

BM Branch Current Monitoring

14 © Copyright 2017 LayerZero Power Systems, Inc.

Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

Zen SSQM Technical Specifications

Zen SSQM Parameters Mains

Voltage (Volts) ü
Voltage Average of Phases (Volts) ü
Voltage Inputs and Output Frequency (Hertz) ü
Total Harmonic Distortion (Percent VTHD) ü
Phase Rotation ü
Current (Amps) ü
Current Average of Phases (Amps) ü
Current Imbalance (Percent) ü
Real Power (kilowatts) ü
Apparent Power (kilovolt-amperes) ü
Current Inputs Reactive Power (kilovolt-amperes reactive) ü
Power Factor ü
Crest Factor ü
Crest Factor Average of Phases ü
Phase Difference Between Sources ü
Phase Difference Between Sources and Output ü
Summary Alarm ü
On Source (1/2/3) ü
Source Fail (1/2/3) ü
Source Preferred (1/2/3) ü
Source 1st Alternate (1/2/3) ü
Source Over/Under Voltage (1/2/3) ü
Alarms Source Over/Under Frequency (1/2/3) ü
Source Not Available (1/2/3) ü
Output Failure ü
Source Overcurrent (1/2/3) ü
Source Exceeds Manual Limit (1/2/3) ü
Source Exceeds Automatic Limit (1/2/3) ü
Bypassed to Source (1/2/3) ü
All product specifications are subject to change without notice.
15 © Copyright 2017 LayerZero Power Systems, Inc.
Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

Technical Specifications

eSTS Models with Withstand Ratings

eSTS Rating (100%) 120/208 V 480 V; 480/277 V; 415/240 V; 600 V; 600/347 V; 575 V
400/230 V; 380/220 V
1600 A 85kAIC; 65kAIC; 42kAIC 85kAIC; 65kAIC; 50kAIC; 42kAIC 65kAIC; 50kAIC; 42kAIC
2000 A 125kAIC; 85kA; 65kA 125kA; 85kAIC; 65kAIC; 50kAIC 85kAIC; 65kAIC; 50kA
3000 A 125kAIC; 85kAIC 125kAIC; 85kAIC; 65kAIC 100kAIC; 85kAIC; 65kAIC
4000 A 150kAIC; 125kA 150kAIC; 125kAIC; 85kAIC 100kAIC; 85kAIC

Mechanical Characteristics *
1600 A 2000 A 3000 A 4000 A
Heat Dissipation 24,200 BTU/Hr 31,800 BTU/Hr 47,200 BTU/Hr 62,700 BTU/Hr
Weight 7,600 lbs 11,000 lbs
Dimensions 152”W x 57”D x 85”H (3861 mm x 1448 mm x 2159 mm) 192”W x 57”D x 91”H (4877 mm x 1448 mm x 2311 mm)
Frame Construction Welded Frame
Electrical Connections Silver-Plated Solid Busbar
Color Textured Powder Coat White (RAL 7035), Blue (RAL 5017), Black, Custom
Floor Stands Optional
Seismic floor stands Optional
Junction Boxes Optional
Sectionalization Engineered Composite Insulation, Dead Front Doors
Electrical Characteristics
Number of Inputs 2, 3 (3 Optional)
Number of Output CBs 1, 2
Frequency 50 Hz, 60 Hz
Poles 3-pole
Phases 3 Phase, 3 Wire, 4 Wire + Ground
Neutral Rating 100%, 150%, 200%
Transfer Time Nominal 1/4- cycle for in-phase sources
Redundancy Single Module Redundancy, Triple Modular Redundancy (Optional)
Circuit Breaker Type Molded Case Switch (Standard), Electronic Trip (Optional)
Circuit Breaker Mounting Type Plug-In
TVSS Standard
Power Quality Monitoring
Power Quality Monitoring Technology Zen SSQM™ (Static Switch Quality Monitoring)
Waveform Capture Local Display, Remote Display via Web Browser, Waveforms Automatically Emailed
Voltmeter Input sources and Output, for each phase
Ammeter Input sources and Output, for each phase
Frequency Meter Both Sources
Synchroscope Phase Angle Meter Between Sources
Metering Apparent Power, Real Power, Power Factor, Output Total Harmonic Distortion
Time Stamped Transfer Count From First Day Use, From Last Reset
CB Status Indicator Open/Closed/Tripped Circuit Breaker
Source Indicator Preferred Source
Power Path Indicator On Live Mimic
*Dimensional & weight data is only valid for 2-source.

All product specifications are subject to change without notice.

16 © Copyright 2017 LayerZero Power Systems, Inc.
Series 70: eSTS 1600 A - 4000 A Static Transfer Switch

Technical Specifications

Operational Characteristics
Transfer Modes Automatic; Manual (via Preferred Source Selection)
Inrush Mitigation Technology Patented Dynamic Phase Compensation Algorithm (U.S. Patent 7,589,438 B2)
Cable Access Top/Bottom
Service Access Front and Rear Access
Bypass Interlock Mechanism Kirk Key
Noise & Interference Isolation Optical Fiber in Critical Control Paths
IR Scan Port Type InSight™ IR Portholes
SCR Type Puck
Display Type 15” Color Touch Screen
Display Resolution 1024x768
Bypass Assistance Voice-Guided Bypass
Audio Bezel-Mounted Stereo Speakers
Languages English, French
Mimic Panel Digital
Setpoints Control Digital
Power Supplies Redundant (4 Failure Groups. Triple Redundant Supplies. 12 Power Supplies Provided.)

Connectivity
Meters Local Display, Ethernet, Modbus/TCP, http via Web Browser (Non-Proprietary)
Alarms Local Display, Ethernet, Modbus/TCP, http via Web Browser (Non-Proprietary)
Summary Alarm Dry Contacts; Local Display; Modbus/TCP; Web Browser
Waveforms Local Display, Ethernet, http via Web Browser (Non-Proprietary)
History/Event Log Local Display, Ethernet, http via Web Browser (Non-Proprietary)
Diagnostics Local Display, Ethernet, http via Web Browser (Non-Proprietary)
Time Synchronization Network Time Protocol (NTP)

All product specifications are subject to change without notice.

17 © Copyright 2017 LayerZero Power Systems, Inc.
 LayerZero Power Systems, Inc.
1500 Danner Drive
Aurora, OH 44202 U.S.A.
Learn more at www.LayerZero.com © 2017 LayerZero Power Systems, Inc.

LayerZero Power Systems, LayerZero.com and the LayerZero logo are registered trademark of LayerZero.
All product specifications are subject to change without notice.
Rev. 4/19 #8