Asco Froment 8800 Series User manual
8800 SERIES High Voltage Load Banks
User Manual
Power
Technologies
© 2000-2018, N J Froment and Co Ltd (‘The Company’).
N J Froment and Co Ltd is part of the ASCO Power Technologies business platform.
Froment and the Froment logo are trademarks or registered trademarks of N J Froment and Co Ltd . All other names and logos referred to are trade names, trademarks or registered trademarks
of their respective owners. The ASCO and ASCO Power Technologies marks are owned by Emerson Electric Co. or its affiliates and utilized herein under license. ©2017 ASCO Power Technologies.
All Rights Reserved.
While every precaution has been taken to ensure accuracy and completeness herein, N J Froment and Co Ltd assumes no responsibility, and disclaims all liability, for damages resulting from use
of this information or for any errors or omissions. Specifications are subject to change without notice.
The Company retains exclusive rights to the intellectual property in any designs, specifications, publications and software described or included herein. The property shall not be used in whole
or part for any purpose other than in connection with the Company’s particular products that this document is intended to accompany. The Company’s identification marks on its products and
documents must not be intentionally removed, concealed or defaced. This document may not be copied or disclosed, in whole or part, without prior written authority; any such authority will
include the condition that this copyright statement remains attached.
ASCO Froment 8800 SERIES load banks are manufactured in the UK by:
N J FROMENT & COMPANY LIMITED,
Easton-on-the-Hill,
STAMFORD,
PE9 3NP,
United Kingdom
Tel: +44 (0)1780 480033
Fax: +44 (0)1780 480044
Web: www.froment.co.uk
8800 SERIES High Voltage Load Bank User Manual
Version 1.1 February 2018
Table of Contents
Introduction
An important note on safety 0 - 2
Chapter One - Introducing Froment Load Banks
Why is Power Supply Testing Required? 1 - 2
• How can a generator be tested eectively?
• The load bank
How do load banks work? 1 - 3
Introducing Froment Load Banks 1 - 4
Froment Load Bank Control Options 1 - 5
• User control interfaces
Non-unity Power Factor Testing 1 - 8
• When is non unity power factor testing required?
• Multiple generator testing
• What equipment is required?
Movable Load Banks 1 - 10
Load Bank Applications 1 - 12
• Generating set testing
Testing UPS systems and batteries 1 - 13
• Site load correction
Using Multiple load banks 1 - 15
Introducing Froment 8800 SERIES Load Banks 1 - 16
8800 SERIES Load Bank Specifications 1 - 17
Chapter Two - Load Bank Installation and Setup
Using a Froment Load Bank Safely 2 - 2
ii
Table of Contents
Transporting Froment 8800 SERIES Load Banks 2 - 4
• Lifting by crane or hoist
• Transport
• Storage
• Packaging
Installing Froment Load Banks 2 - 5
• Location
• Sound attenuators
• Avoiding hot air re-circulation
Electrical Installation 2 - 8
• Voltage and frequency ratings
• Connecting the external supply
• Anti-condensation heaters and lighting supply
• Connecting the Supply-on-Test
• Supply-on-test general points
Control System Connections 2 - 15
• High Voltage (HV) instrumentation mode
• Low Voltage (LV) instrumentation mode
• System monitor control
• Optional remote connections
Commissioning 2 - 14
Chapter Three - Load Bank Operation
Before Operating the Load Bank 3 - 2
• Safety warning
Controlling the Load Bank 3 - 3
The Control Room 3 - 4
• The external power inlet compartment
• Main control panel
• System monitor
• Operating the ring main unit (RMU)
• Status indicator lamp operation
• Fault indicators
Emergency Shutdown Procedures 3 - 11
Load Function Test 3 - 12
Load Bank Operation using a Remote Control 3 - 15
iii
Table of Contents
iv
Chapter Four - Hand-held Reference Guide
The Sigma Hand-held 4 - 2
Firmware Updates 4 - 3
Connecting the Hand-held to the Load Bank 4 - 3
The Hand-held Keypad 4 - 4
The Hand-held Menu Display System 4 - 5
Using the Sigma Hand-held 4 - 8
Hand-held Quick Start 4 - 9
Using the Settings Pages 4 - 10
The Options Page 4 - 15
The Test Pages 4 - 19
Manual Test Mode 4 - 23
Auto Test Mode 4 - 27
Chapter Five - Maintenance & Troubleshooting
Safety Warning 5 - 2
Routine Maintenance Procedures 5 - 3
• Daily
• Monthly
• Annually
Ring Main Unit (RMU) Maintenance 5 - 4
• Housing exterior
• Housing interior
• Leakage of SF6 gas
• Service life
Transformer Maintenance 5 - 5
Fault Finding 5 - 5
Table of Contents
v
Sigma 2 Load Bank Status Display 5 - 6
• Sigma 2 normal operation
• Warnings
• Errors
Froment Load Bank System Monitor 5 - 11
• Startup Screen
• Navigation
• The Meters Screen
• I/O Screen
• Status Screen
Appendices
8800 - Installation Diagrams A - 2
Transformer Commissioning A - 3
Transformer Maintenance Schedule A - 4
Certificate of Conformity A - 7
Electromagnetic Compatibility A - 8
Useful Equations A - 9
Introduction
This manual provides you with all the information that you need to safely install and operate Froment
8800 SERIES load banks. High voltage equipment can be dangerous, please ensure you have followed
all local rules and regulations regarding working with high voltage.
The manual is divided into five chapters:
In addition to these five chapters there are a number of Appendices containing information that did
not fit easily within the main body of the text. These include installation drawings, a certificate of
conformity, and some information about electromagnetic compatibility.
Chapter One provides an introduction to the general principles of power supply testing
and explains how a Froment Load Bank makes the process easier, safer and more
reliable. It then provides an introduction to the 8800 SERIES load banks and their main
features.
Chapter Two covers all of the procedures that need to be carried out before a load
bank can be put into operation. It explains how to install the unit safely and how to
commission it to check that it will operate correctly.
Chapter Three explains the basics of how to operate the load bank. It describes the
load bank controls and explains how they are used in an emergency. This chapter also
explains how the load bank can be operated when an Hand-held or other control unit
is not available.
Chapter Four provides a detailed reference to the Sigma Hand-held, including details
of its more advanced features for Low Voltage use.
Chapter Five covers the maintenance procedures you will need to follow to keep a
8800 SERIES load bank operating correctly. It also explains how to troubleshoot should
a problem occur.
Chapter One
An Important Note on Safety
All Froment load banks are designed with safety as a very high priority, but their operation does
present some risks. In common with other test equipment, the safety of all concerned is dependent
on the way that the unit is operated. Do not use this equipment unless you have read and understood
this manual, and are familiar with the accepted practice for the industry. The equipment should not
be used by unskilled personnel. Misuse could result in serious injury and damage to the equipment.
Be sure to follow all of the safety warnings in this manual. In particular, pay careful attention to the
following points:
• Keep all personnel who are not directly involved with tests well away from the load bank and the
equipment under test.
• The discharge air can be very hot and could cause serious flesh burns. Do not touch the outlet
grille while the load bank is running, or for a few minutes afterwards.
• Ensure that there is no risk of the hot discharge air re-circulating back to the air inlet of the load
bank, extensive damage is possible due to short-circuiting the cooling air.
• Ensure the air inlet and outlets are completely unobstructed and that there is no loose paper,
plastic bags, or other debris that may be drawn on to the air inlet grille, obstructing the airflow.
• Combustible material left near the air discharge should be removed.
• Only operate the load bank with all the guards in place, with doors closed and with all of the
covers and protective screens securely in position.
• Always route cables into the terminal compartment through the gland plate or strain relief
system provided.
• Make sure that all equipment is adequately grounded; this applies equally to the Supply-on-Test,
and the load bank.
• Ensure all cables are in good condition and adequately rated for the planned load, and that all
connections are securely made.
• Ensure all cables are long enough to lay in smooth curves, and are unstressed, undamaged, and
protected from mechanical damage. Lay the cables to minimise the risk of personnel tripping or
accidentally tugging on the cables.
• Do not switch o the cooling fan immediately after a test. Allow the fan to run for 5 minutes after
removing the load.
• Store the equipment in a clean, dry place when not in use. Only install and operate the load bank
in environmental conditions suited to the enclosure classification of the load bank.
Chapter One
Introducing Froment Load Banks
If you are not familiar with the use of Froment Load Banks then you should start with this chapter. It
provides an introduction to the general principles of power supply testing and then it explains how a
Froment load bank makes the process easier, safer and more reliable.
If you are an experienced load bank user you may want to skip the earlier sections, but you should
certainly read the introduction to Froment 8800 SERIES load banks which appears at the end of the
chapter.
Chapter One
1 - 2
Why is Power Supply Testing Required?
There are many dierent ways of generating electrical power and many reasons why
generating equipment may be required. All of them have at least one thing in common: it
is essential that the generator be capable of operating eectively at its maximum rated
output when it is required.
Unfortunately, it is not so easy to be absolutely sure that this will be the case. Many
generating sets operate at a fraction of their rated output for a large proportion of the
time, and many others are intended to run in an emergency situation which may occur only
occasionally.
In both cases the only way to ensure that generating equipment is capable of providing
the performance required is to regularly test it whilst it is operating at its full rated output.
The various regulatory authorities and other concerned parties such as insurance
companies are aware of this, and the testing of new installations is mandatory. In many
cases there is also a requirement for regular testing for existing equipment, particularly
those that provide emergency or standby power supplies.
How can a generator be tested eectively?
The answer to this is very straightforward: apply a load that is equivalent to the generator’s
maximum output and then run the generator and observe how it performs.
The careful measurement of the generator’s output will reveal any problems with its ability
to meet the specification. Then, after repairs or modifications have been made, the test
can be repeated to verify that the fault has been rectified.
The load bank
For reliable testing it is important to provide a load that is a precise match for the generator’s
output. It must provide a consistent and repeatable load so that the test can be accurately
measured and recorded and it must also be capable of dissipating the large amount of heat
that is generated during the test. And, it is critically important that the test does not put
the site load at risk.
To achieve all this requires a specialist item of equipment: the load bank. These consist
of an array of load elements combined with a control system designed to ensure that a
precise load can be applied in safety.
Introducing Froment Load Banks
1 - 3
+
+
_
_
AV
How Do Load Banks Work?
Load banks are complex precision engineered machines, but to explain the general
principal we can provide a very simple model of how they work:
Figure 1-1 Basic DIY generator output test system.
Figure 1-1 shows the general arrangement of a very basic DIY generator testing system.
It’s simple, but it contains the four basic items necessary to test a generating set safely:
1. The fan heater’s heating elements provide an electrical load that is large enough to
ensure that the generator runs at full capacity.
2. The fan heater’s switch gear provides a control system that will ensure that the load
can be applied safely, and in a way that will not cause damage to the generator and its
control circuits, or injury to the personnel running the test.
3. The fan in the fan heater provides a method of safely dissipating the considerable
amount of heat generated by the test.
4. The voltmeter and ammeter provide instrumentation that will allow the results of the
test to be monitored.
Of course, this kind of arrangement can provide only a crude test for a low powered
generator and its ability to match the generator’s output accurately is very limited. As the
output of the generator increases, the cabling, switchgear and control equipment required
for this becomes increasingly heavier and more sophisticated. In addition, because of the
large amount of heat generated during testing, the issue of how to conduct the test safely
becomes increasingly significant.
Chapter One
1 - 4
Introducing Froment Load Banks
Froment load banks are purpose designed to provide all of the facilities needed to quickly,
safely and reliably test generating equipment with outputs up to several megawatts.
Figure 1-2 Froment load bank core components
There are many variations between dierent Froment load bank models, but Figure 1-2
shows a simplified schematic of the core components to be found in most units.
The diagram contains:
• An array of load elements grouped in small steps that are individually activated by
switchgear to allow the load applied to the generator to be precisely controlled.
• A fan and duct forced air system which ensures that the heat generated during testing
is vented safely to atmosphere.
• Fuses and safety interlocks that ensure that the test can be shut down in a controlled
fashion if any problems occur.
• A microprocessor based control and three phase instrumentation system connected to
a number of highly accurate voltage and current transformers. This provides automatic
precision control of the test and allow the results to be displayed with better than 0.5%
accuracy.
Cold air
inlet
Fan
motor
Air duct
Fan
contactor
Step 1Step 1Step n
Load Elements
Hot air
outlet
Supply-on-test
Remote control
unit
External supply for
fan and controls
Sigma II
load bank
controller
Front panel controls
Load
contactors
Fuses
Phase
rotation
sensor
Current/Voltage
Transformers
© NJ Froment & Co. Ltd. This document may not be copied
or disclosed in whole or part witho ut prior written authority.
Introducing Froment Load Banks
1 - 5
Froment Load Bank Control Options
Reliable testing requires precise control of the load applied to the generator and accurate
real-time measurement of the generator’s output.
To achieve this, most Froment load banks are fitted with a Sigma 2 load control system.
Sigma 2 is a microprocessor-based control and instrumentation system specifically
developed for load bank applications.
Sigma 2 provides precise control over the operation of each load element during the test
whilst simultaneously measuring the results. The unit also provides safety monitoring and
interlocks which shut down the load bank safely should a problem occur.
Figure 1-3 Sigma 2 load bank control unit.
User control interfaces
The wide variety of dierent applications for load banks require a wide variety of user
control interfaces. These range from a very basic switch controlled system through to
sophisticated computerised control, instrumentation and data logging systems.
All Froment load banks are supplied with a built-in switch plate which contains a Fan and
Controls Supply Isolator, Start and Stop switches and (for Sigma2 controller equipped
units) Sigma control cable connectors.
The switch plate may contain other controls, depending on the specific load bank variant.
Depending on the application, the Sigma controller unit can be operated by a number of
dierent control interfaces. These include:
Chapter One
1 - 6
Sigma Hand-held. The Hand-held provides load control and instrumentation on Sigma
controlled load banks.
Figure 1-5 Sigma Hand-held
The Hand-held contains a membrane keyboard and built in display unit and is connected
to the load bank by a control cable. The Hand-held’s simple user interface provides a way
for generator tests to be conducted in an intuitive way with minimum of calculation.
Sigma PC Load Control Software. As an alternative to the Hand-held, the load bank can
be connected to a PC running Froment Sigma PC Load Control software.
This Windows™ application provides all of the facilities of the Hand-held with an enhanced
user interface, improved instrumentation and facilities for response analysis, data
acquisition, and reporting. Test data can be exported for use by other applications such as
Microsoft™ Excel.
© NJ Froment & Co. Ltd. This document may not be copied
or disclos ed in whole or part witho ut prior w ritten authority.
Introducing Froment Load Banks
1 - 7
Figure 1-6 Sigma PC Load Control Software
Sigma Modbus Interface. Every Sigma controlled load bank has the capability to be
remotely controlled using the industry standard Modbus serial communications protocol.
This will allow the load bank to be integrated with a wide range of test, automation,
supervisory and monitoring systems. Modbus control is beyond the scope of this manual.
If you need more information please contact the Froment technical support department.
Note: Both the Hand-
held and the PC soft-
ware can control up to
14 Sigma controlled load
banks simultaneously.
Tests can be run manu-
ally or automatically us-
ing a pre-programmed
test sequence.
Chapter One
1 - 8
Non-unity Power Factor Testing
It is unusual for a generator to be presented with a purely resistive load. In real-world
applications it is much more likely that the load is made up of a combination of resistive,
inductive and capacitive elements (electric motors, lamp ballasts, etc.) which may be
continuously changing as various items of equipment are switched on and o.
The inductive and capacitive (reactive) parts of the load tend to store and then return
energy, and some proportion of the power supplied to the circuit is returned to the
generator. Consequently, more current has to flow to provide the required amount of
power to the circuit and the circuit is said to have a low (or non-unity) power factor. For
instance, to get 1kW of real power, a load with a power factor of 0.8 will require 1.25 kVA
apparent power to be supplied.
Figure 1-7 Typical power curve for power factor of 0.8
A low power factor puts additional stresses on alternators, voltage regulators, and switch
gear without necessarily putting additional load on the engine. Many generating sets are
designed to reach their maximum output when connected to a non-unity power factor
load.
To provide a realistic test, it is necessary for the load bank to simulate this situation. To
achieve this, the load bank elements need to consist of a mixture of resistive heating
elements and inductors. In some applications, capacitors are also used.
Voltage
Current
Power
0
Proportion of power
returned to the source
Introducing Froment Load Banks
1 - 9
When is non unity power factor testing required?
This depends on the type of test that is required.
Sometimes, for smaller generators where a standardised alternator design is in use, the
electrical performance of the alternator and control gear can be assumed to be adequate.
In this case the only requirement during testing is to prove that the motive source of
the generating set is capable of operating at full power without overheating and a purely
resistive load is all that is required. This is sometimes referred to as active load (power
factor 1.0) or unity power factor.
However, in many situations the electrical performance of a generating set is of critical
importance. In these cases it is necessary to put the motive source, alternator and its
associated control gear all under stress during testing. To do this a combined load made
up of resistive and reactive elements is required.
Combined loads are also required to set up systems where multiple generating sets are
running in parallel or where it is necessary to simulate the start up of a large motor.
Multiple generator testing
Multiple generating sets running in parallel can present a problem for installers when it
comes to setting up load sharing and voltage regulation on a new system. A purely resistive
load will not provide the required load characteristics and a combined load is required for
initial calibration and testing.
What equipment is required?
Combined load testing can be accomplished by using a combined load bank (a load bank
consisting of a mixture of resistive and reactive load elements) or by running two or more
dierent type load banks in parallel.
The exact combination of equipment required will depend on the specific application.
Typically power factors from 1.0 to 0.7 are used but motor start simulation may require
a power factor as low as 0.4. See the appendices of this manual for more details of the
calculations involved.
Note: Froment com-
bined, inductive and
capacitive load banks
are in the 6000 SERIES
range. Froment purely
resistive load banks
are in the 3000 SERIES
range and Froment con-
tainerised units are in
the 8000 SERIES range.
Chapter One
1 - 10
Movable Load Banks
Many Froment load banks are supplied for applications where they will be permanently
installed at a particular site location. However, in some applications the load bank is as a
temporary measure that is only required whilst generator tests are carried out.
This is quite common, for instance, with a new generator installation where the load bank
is used during commissioning and acceptance testing.
Figure 1-8 Additional components required for a movable load bank
Because of the temporary nature of the installation there are some specific design
dierences between a load bank intended for permanent installation and one intended to
be “movable”.
These include:
External power supply inlet. The load bank’s fans and control electronics can be powered
by the generator under test or (as recommended by Froment) a completely separate,
external power source. To make providing external power simple on a movable load bank,
a suitably rated IEC60309 connector is mounted on the unit either externally or behind a
lockable door with cable access.
Hot air
outlet
Cold air
inlet
Fan
motor
Air duct
Sigma II
Load bank
controller
Front panel controls
Load elements
Load
contactors
Fan
contactor
Current/Voltage
Transformers
Supply-on-test
External supply for
fan and controls
Remote control
unit
Step 1 Step 2 Step n
Fuses
Phase
rotation sensors
Supply
selector
© NJ Froment & Co. Ltd. This document may not be copied
or disclosed in whole or part wit hout prior written authority.
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