Kohler PowerWave 9000DPA S2 User Manual

PowerWAVE 9000DPA

S2 (30-250 kVA)

User Manual

TS_619_00 PW9000DPA S2 User Manual 13/3/17

TS_619_00 PW9000DPA S2 User Manual 13/3/17

Document Control

PDF ISSUE DATE REVISION SUMMARY

TS_619_00B 19/01/17 Second draft copy

TS_619_00C 27/01/17 Third draft copy

TS_619_00D 09/03/17 Fourth draft copy

TS_619_00 13/03/17 First Issue

TS_619_00 PW9000DPA S2 User Manual 13/3/17

Uninterruptible Power Supplies Ltd has taken every precaution to
produce an accurate, complete and easy to understand manual and will
therefore assume no responsibility nor liability for direct, indirect or
accidental personal or material damage due to any misinterpretation of or
accidental mistakes in this manual.

© 2017 Uninterruptible Power Supplies Ltd

This manual may not be copied or reproduced without written permission
of Uninterruptible Power Supplies Ltd.

USEFUL CONTACTS

www.upspower.co.uk UPS Limited web site

[e-mail] Service department – booking service, fault reporting etc.

[e-mail] Technical queries

[e-mail] Hardware sales

[e-mail] Extended warranty agreements etc

TS_619_00 PW9000DPA S2 User Manual 13/3/17 I

Table of Contents

Safety 1

1.1 Description of symbols used in this manual 1-1

1.2 User precautions 1-1

General Description 2

2.1 General introduction 2-2

2.1.1 Reliability and quality standards 2-2

2.1.2 Advanced design features 2-2

2.2 PW9000DPA S2 Model range 2-4

2.3 Functional description of operation 2-5

2.3.1 PW9000DPA S2 module block diagram 2-5

2.3.2 UPS Module operating modes 2-7

2.3.3 UPS System operating modes 2-9

2.3.4 Parallel system operation 2-10

2.4 PW9000DPA S2 User controls 2-11

2.4.1 DPA-50 Component identification 2-12

2.4.2 DPA-150 Component identification 2-13

2.4.3 DPA-250 Component identification 2-14

2.5 UPS Interface facilities 2-15

2.5.1 Customer Interface Board 2-15

2.5.2 Parallel Interface Board 2-16

2.6 Module control panel 2-16

2.6.1 Module control panel buttons 2-16

2.6.2 Module mimic LEDs 2-17

2.6.3 Power Management Display (PMD) 2-17

2.7 Warranty 2-21

2.8 Extended Warranty 2-21

2.9 Additional Service/Maintenance Support 2-21

Installation 22

3.1 Introduction 3-22

3.2 Taking receipt of the UPS 3-22

3.2.1 Reporting transportation damage 3-22

3.2.2 Weight and dimensions 3-23

3.2.3 Local transportation 3-23

3.2.4 Storage 3-24

3.2.5 Unpacking 3-24

3.3 Installation planning (environmental & mechanical) 3-25

3.3.1 Environmental considerations 3-25

3.3.2 Clearances 3-25

3.4 Installation planning (electrical) 3-27

3.4.1 General requirements 3-27

3.4.2 External maintenance bypass switches 3-29

3.4.3 Cable sizing 3-30

:

II TS_619_00 PW9000DPA S2 User Manual 13/3/17

3.4.4 UPS Power connections 3-32

3.4.5 Battery configuration 3-33
External battery enclosure with separate battery configuration 35
External battery enclosure with common battery configuration 36

3.5 UPS Cabling procedure 3-37

3.5.1 Safety notes 3-37

3.5.2 Preparing the UPS power cabling 3-37

3.5.3 Connecting the UPS AC power cables 3-37

3.5.4 Connecting the battery cables 3-38

3.6 Customer Interface Board 3-38

3.6.1 Customer dry-port interface terminal block – X1 3-38

3.6.2 Customer interface output terminals – X2, X3, X4 3-39

3.7 Parallel-cabinet control and configuration 3-40

3.7.1 Parallel control bus 3-40

3.7.2 Multidrop 3-40

Operating Procedures 41

4.1 Introduction 4-41

4.1.1 Commissioning 4-41

4.1.2 Operating procedure summary 4-41

4.1.3 General warnings 4-42

4.2 Operating instructions 4-42

4.3 How to start the UPS system from a fully powered-down condition 4-42

4.4 How to start the UPS system from the maintenance bypass 4-44

4.5 How to transfer the load to maintenance bypass 4-45

4.6 How to shut down the complete UPS system 4-46

4.7 Operating in ‘on bypass’ mode 4-47

4.7.1 How to Turn ON the UPS in ‘on bypass’ mode 4-47

4.7.2 How to Turn OFF the UPS in ‘on bypass’ mode 4-47

4.7.3 How to transfer between ‘on bypass’ and ‘on inverter’ mode 4-47

Maintenance 48

5.1 Introduction 5-48

5.2 Scheduled maintenance 5-48

5.2.1 Preventative maintenance inspection 5-48

5.2.2 System calibration 5-48

5.2.3 Battery maintenance and testing 5-49

Troubleshooting 50

6.1 Alarms 6-50

6.2 Menu, Commands, Event Log, Measurements, 6-50

6.3 Fault identification messages and alarms 6-51

6.4 Contacting service 6-51

Options 52

7.1 Introduction 7-52

7.2 Customer interface board 7-53

7.2.1 Remote shut down customer input 7-53

7.2.2 Generator ON customer input 7-53

7.2.3 Battery temperature sensor 7-54

7.2.4 RS232 Computer serial interface – JD11 & USB 7-54

7.2.5 RS232 Interface for multidrop – JD12 7-54

7.2.6 SNMP/ CS141 slots – SLOT 1/ SLOT 2 7-55

TS_619_00 PW9000DPA S2 User Manual 13/3/17 III

:

Specification 56

8.1 Mechanical Characteristics 8-56

8.2 Input Characteristics 8-57

8.3 Battery 8-57

8.4 Output 8-58

8.5 Standards 8-58

8.6 Environmental 8-59

:

IV TS_619_00 PW9000DPA S2 User Manual 13/3/17

TS_619_00 PW9000DPA S2 User Manual 13/3/17 1

1

Safety

1.1 Description of symbols used in this manual

1.2 User precautions

WARNING: The warning symbol is used where there is danger of an electrical shock, equipment damage or

personal-injury.

CAUTION: The caution symbol is used to highlight important information to avoid possible equipment
malfunction or damage.

WARNING: Keep this manual with the UPS for future reference.

WARNING: The UPS and peripheral equipment must be installed and commissioned by suitably qualified and

trained personnel who are aware of the potential shock hazards.

WARNING: Do not attempt to install this UPS system until you are satisfied that ALL the safety instructions and
hazard warnings contained in this manual are read and fully understood.

WARNING: High leakage current!
Ensure that the UPS has been correctly earthed before you connect the mains power supply!

WARNING: This UPS must not be started-up or put into use without having first been commissioned by a fully
trained engineer authorised by the manufacturer.

WARNING: All servicing must be performed by qualified personnel. Do not attempt to service the UPS
yourself.
You run risk of exposure to dangerous voltages by opening or removing the UPS-covers! Uninterruptible
Power Supplies Ltd will assume no responsibility nor liability due to incorrect operation or manipulation of the
UPS.

WARNING: The PW9000DPA S2 is a Class A UPS product (according to EN 62040-3). In a domestic
environment the UPS may cause radio interference. In such an environment the user may be required to
undertake additional measures.

2 TS_619_00 PW9000DPA S2 User Manual 13/3/17

2

General Description

2.1 General introduction

Congratulations on your purchase of the PW9000DPA S2 UPS.

Continuous power availability is essential in today’s dynamic IT and process-related work environments. It is equally
important that any installed power protection system is sufficiently resilient and adaptable to handle any changes brought
about by the introduction of new server technologies, migration and centralization.

Such demands are well met by the PW9000DPA S2 UPS system which provides the foundation for continuous power
availability of network-critical infrastructures both in enterprise data centres, where business continuity has paramount
importance, and in process control environments where manufacturing continuity is essential.

The PW9000DPA S2 is a second generation high-power-density (HPD), leading-edge, double-conversion power
protection technology that has standardised on a modular component approach which helps speed deployment, improve
adaptability and increase system availability, while reducing total cost of ownership. It is a unique on-demand architecture
that integrates the power rack, power distribution unit, back-up battery and monitoring and management solutions to allow
easy selection of optimised configurations.

2.1.1 Reliability and quality standards

High reliability, upgrade ability, low operating cost and excellent electrical performance are just some of the highlights of
this innovative UPS solution.

By using a unique modular construction, and incorporating the latest technological developments in power engineering,
the PW9000DPA S2 represents a completely new generation of transformerless 3 phase UPS-System. Its advanced
double conversion VFI (Voltage and Frequency Independent) topology responds fully to both the highest availability and
environmentally friendly requirements compliant with IEC 62040-3 (VFI-SS-111) standards. The criteria and methods
which are used in the design, manufacture, and maintenance of Uninterruptible Power Supply systems are certified to
International Standard ISO 9001/EN 29001 and ISO 14001. A full UPS Specification is given in Chapter 8 of this manual.

Uninterruptible Power Supplies Ltd. specialises in the installation and maintenance of Uninterruptible Power Systems; and
this powerful UPS is just one example of our wide range of state-of-the-art power protection devices that will provide your
critical equipment with a steady and reliable power supply for many years.

2.1.2 Advanced design features

Key features

The highlights of this innovative UPS solution include:

• Decentralised Parallel Architecture (DPA) – Highest availability, with near zero down time.

• Truly modular design – The PW9000DPA S2 is designed around 30kVA, 40kVA,or 50kVA UPS modules.

• Hot-swappable modules – Enables system expansion and module replacement in a live system.

• Compact size, small foot print – Up to 342kW/m² saving on expensive floor space.

• Flexible battery management – Advanced management of battery charging and preventive-failure diagnostics.

• High ac-ac efficiency (up to 95.5%) even with partial loads – Results in energy and operational cost savings (TCO)

• Full power available from 0.9 lead to 0.8 lag – No de-rating required with leading power factor loads.

• Very low input current distortion – THDi = <3% @ 100% load leads to savings in generator-set power and

installation costs.

TS_619_00 PW9000DPA S2 User Manual 13/3/17 3

2: General Description

Hot-swappable modules

In a redundant module system the unique ‘hot-swappable’ feature enables a UPS module to be added or removed from its
cabinet whilst the system is still powered. This can be done without disturbing the load or transferring it to the bypass
supply.

Note: In a non-redundant system the load will unavoidably have to be transferred to the bypass supply while a module is
shut down or removed from the system.

Advanced booster technology

The UPS module’s inbuilt advanced booster technology results in a perfect sinusoidal input power quality at 0.99 input
power factor with a harmonic content of less than 3-4% THDi. This leads to a more reliable system operation together with
savings in generator and transformer sizing due to reduced winding losses. It also means that the traditional input
harmonic filters, still used by some systems, are not required.

The high power factor presented by the UPS on the incoming mains supply minimises cabling and fusing costs due to the
reduced reactive power consumption which, together with the accompanying low harmonic currents, provides the
following benefits:

• No additional losses in wires and cables

• No extra heating of transformers and generators

• No over sizing of generators

• No false circuit breaker tripping and malfunction

• No erratic operation of computers, telecommunications, monitors, electronic test equipment etc.

• No resonance with power factor correction capacitors

Decentralised Parallel Architecture (DPA)

The PW9000DPA S2 system features DPA paralleling technology that provides n+x redundancy without introducing a
single-point-of-failure. Each module contains its individual charger and inverter power units, bypasses, CPUs, control
panels and separate battery configuration, and thereby offers completely autonomous operation.

This unique decentralized design:

• Enables a parallel redundant system providing 100% conditioned power at all time.

• Eliminates the system-level single point of failure inherent in traditional parallel UPS systems.

• Exponentially increases the reliability of the overall system.

Flexible battery management (FBM)

This equipment employs flexible battery charging management which avoids premature deterioration of battery life and
provides preventive failure diagnostics. The major benefits are:

• AC-ripple-free battery charging due to a dedicated dc-dc charger independent from the rectifier and inverter.

• Wide range of number of battery blocks (42-50 x 12V blocks, depending autonomy times).

• Wide UPS input voltage operating window extends the battery life due to fewer discharge cycles.

• Battery discharge protection caused by load jumps.

• Proactive battery protection from false manipulations and inadequate charging voltages.

• Proactive battery failure detection thanks to the Advanced Battery Diagnosis (ABD) algorithm.

• User-selectable battery tests to ascertain the battery state.

• Optional temperature compensated charging regime to enhance battery life.

2: General Description

4 TS_619_00 PW9000DPA S2 User Manual 13/3/17

2.2 PW9000DPA S2 Model range

The PW9000DPA S2 UPS incorporates a rack-mountable design based on 30kVA, 40kVA and 50kVA plug-in UPS
modules fitted into one of three purpose-built cabinets. Each module is a self-contained UPS comprising a rectifier, battery
charger, inverter and static switch; and when two or more modules are fitted into a cabinet they effectively operate as a
parallel UPS system. The available cabinets are shown below in Figure 2.1.

The PW9000DPA S2 cabinets are identified as CLASSIC DPA-50, TRIPLE DPA-150 and UPGRADE DPA-250 – where
the model number represents the maximum kVA output when the cabinet is fully populated with 50 kVA UPS modules.
Figure 2.1 shows that the DPA-50 and DPA-150 cabinets also contain the UPS batteries; however the DPA-250 cabinet
requires an external battery cabinet, or battery rack. Uninterruptible Power Supplies Ltd. can supply a matching battery
cabinet which can installed adjacent to the DPA-250 cabinet in the majority of installations. An external battery cabinet can
also be added to the DPA-50 and DPA-150 models to extended the system’s autonomy time if desired.

Figure 2.1 PW9000DPA S2 Cabinets (frames)

Figure 2.2 PW9000DPA S2 UPS Modules

CAUTION: All the modules fitted within a cabinet must be of the same ra ting – for example, it is not possible to
mix 30kVA and 50kVA modules in the same cabinet.

CLASSIC DPA-50 TRIPLE DPA-150 UPGRADE DPA-250

UPS module capacity
Battery capacity

Max 1 module (30-50kVA)

280 x 7/9Ah batteries

3 modules (30-50kVA) 240x

7/9Ah batteries

5 modules (30-50kVA)

External batteries

Maximum power connection kVA 50 150 250

Dimensions (WxHxD) mm 730x1650x800 730x1975x800 730x1975x800

Weight of empty frame kg 262 239 205

Weight of frame with modules
fitted (but without batteries)

kg 305 - 309

(with 1 Module)

368 - 379

(with 3 Modules)

420 - 439

(with 5 Modules)

Colours Front: RAL 9007 + black (inlets). Sidewalls: Graphite grey

DPA 30 S2 Module DPA 40 S2 Module DPA 50 S2 Module

Output Apparent Power KVA 30 40 50*

Output Active Power KW 24 32 40

Output Power (PF=1) KVA / KW 24 / 24 32 / 32 40 /40

Number of 12V Battery Blocks No. 42-50 42-50 42-50

Dimensions (WxHxD) mm 663 x 225 x 720

Weight kg 43.1 45.3 46.8

Colours Front: Graphite grey

* On Inverter mode 50 KVA/40kW on Bypass mode 45 KVA/40kW

TS_619_00 PW9000DPA S2 User Manual 13/3/17 5

2: General Description

2.3 Functional description of operation

This section describes:

• The internal operation of an individual UPS module at block-diagram level (see paragraph 2.3.1)

• The various operational modes of an individual UPS module (see paragraph 2.3.2)

• UPS system operational modes – ‘On-line’ versus ‘Off-line’ system operation (see paragraph 2.3.3)

• Multi-module system operation and paralleling considerations (see paragraph 2.3.4)

2.3.1 PW9000DPA S2 module block diagram

The PW9000DPA S2 UPS module is rack-mounted within the cabinet, and when the module is inserted into its rack it
plugs into a heavy-duty connector fitted to the back of the rack which carries all the module’s power connections – i.e.
input mains, bypass mains, battery and module power output.

Figure 2.3 PW9000DPA S2 module

Input power connections (1) / (2)

The UPS input mains and bypass mains are connected to an input power terminal block located in the lower part of the
UPS cabinet. Both inputs require a 3ph+N feed but, although the two inputs are shown as being separate in Figure 2.3, in
a standard installation the input mains terminals (1) and bypass mains terminals (2) are usually linked at the cabinet’s
input power terminal blocks so only one mains supply feed is required.

The input supplies are unswitched within the UPS cabinet and connected directly to each fitted module.

Both input supplies are fused within the module (F1/F2), however the fuses are internal to the module and not accessible
to the operator. In the event of a fuse failure the module must be removed and repaired by an authorised service agent. A
fuse failure event is shown on the module control panel to identify a faulty fuse.

Within the UPS module, the input supplies are connected to the module’s power blocks through individual supply
contactors which are driven by the module’s control logic and operate as part of the module’s start/stop sequences. They
are also used by the control system to isolate the input power within the module following certain fault conditions.

CAUTION: As the mains power supplies are unswitched within the UPS cabinet, the module(s) will be live at all
times unless the input/bypass supply is isolated at the external mains switchboard panel.

RECTIFIER

BATTERY

EXTERNAL

BATTERY
CABINET

INVERTER

STATIC

SWITCH

BOOSTER /

CHARGER

Bypass

Contactor

Inv. Output

Contactor

Input

Contactor

Bypass Mains

IA-2

IA-1

F4

F1

F2

F3

UPS MODULE

UPS CABINET

Static bypass line

Maintenance bypass line

UPS Input Mains

UPS Output
to critical load

3

4

1

2

5

6

7

8910

2: General Description

6 TS_619_00 PW9000DPA S2 User Manual 13/3/17

Battery connections (3)

Each UPS module is connected to a battery string via a dedicated fused isolator. Ideally, each module is connected to an
individual battery but in some installations a common battery is shared between two (or more) modules.

The battery fuse (F3) is fitted inside the module and is not accessible to the operator. If the fuse ruptures, the module must
be removed and repaired by an authorised service agent. A fuse failure message is shown on the module control panel.

• DPA-50 (1 module) – The batteries are housed internally in the UPS cabinet and connected to the module through
a fused isolator (F4) located on the cabinet’s power panel.

• DPA-150 (3 modules) – The batteries are housed internally in the UPS cabinet and connected to the module
through three fused isolators annotated F4/ F5/ F6 (for modules 1, 2, and 3 respectively).

• DPA-250 (5 modules) – The batteries are housed in a separate battery cabinet (or rack) which must also contain
the fused isolators. There are no battery isolators within the UPS cabinet itself.

Output power connection (4)

A ‘parallel isolator’ switch (IA-2) is connected between the UPS module output and the cabinet’s output (load) terminal
block. IA-2 is used to disconnect the module from the UPS output; for example, when replacing a module in a redundant
parallel system, or when operating on maintenance bypass.

In the DPA-150 and DPA-250 cabinets, a dedicated ‘parallel isolator’ switch (IA-2) is provided for each UPS module. The

isolators are located on the cabinet’s power panel and identified as IA2-1, IA2-2, IA2-3.... (for modules 1, 2, and 3

respectively)

Maintenance bypass (5)

The maintenance bypass switch (IA-1) is external to the UPS module(s) and located on the cabinet’s power panel. This
switch connects the UPS cabinet output (load) terminals directly to the bypass mains terminals and is used to connect the
load to the (unprotected) bypass supply if the UPS modules have to be shut down due for service repair etc. See also
paragraph 3.4.2.

Rectifier (6)

The rectifier converts the UPS input mains supply into a regulated DC power source which provides the operating power
for the inverter. It uses leading-edge switched-mode techniques which results in a UPS module input power factor of
almost unity over its operating range (0.99 at full rated linear load). The rectifier can provide 100% inverter power demand
over an input voltage range of -20% to +15%. This wide input voltage operating range means that the battery is not called
upon during substantial power dips (brown outs), which in turn maximises the battery life and availability.

Battery booster/charger (7)

This block has bi-directional functions. When the input mains supply is available, and the rectifier is turned on, the booster/
charger acts as a multi-stage battery charger. The charger uses an intelligent charging profile to optimise the battery life
and at the same time ensure the battery recharges quickly following a deep discharge cycle.

If the input mains supply fails, or the rectifier is unable to provide a sufficient output to satisfy the prevailing inverter load,
the battery provides the inverter’s DC operating power source. The booster/charger circuit boosts the battery voltage as
the battery discharges and regulates it at a suitable level to allow the inverter to operate correctly.

Inverter (8)

The inverter converts the DC voltage produced by the rectifier (or the battery via the DC boost converter) into a sinusoidal
AC output voltage suitable to connect to the load. In addition to providing output voltage regulation, the inverter control
logic also provides various levels of overload protection, freq

uency regulation and synchronisation, and output voltage

error detection.

Static switch (9)

The static switch provides a means of connecting the UPS module output to the static bypass line – which is in turn
connected to the UPS bypass mains supply. Working in conjunction with the output contactor, the static switch control
logic is used to transfer the UPS output between the inverter and bypass mains without a break in the load supply.

Note: A brief load break will occur if transferring from bypass to inverter following a bypass supply failure. (See ‘Off Line
Mode’ in paragraph 2.3.3).

TS_619_00 PW9000DPA S2 User Manual 13/3/17 7

2: General Description

Inverter output contactor (10)

The inverter output contactor is driven by the UPS module’s control logic and operates in conjunction with the static switch
as part of the bypass/inverter load transfer process. The contactor is also used to isolate the inverter from the UPS output
within the module following certain overload or fault conditions.

2.3.2 UPS Module operating modes

Simplified block diagrams are used in this section to illustrate the various UPS module operating modes. Note that where
two or more UPS modules are installed in a DPA-150 or DPA-250 cabinet they will always adopt the same operating mode
due to their parallel control signals.

Load on inverter

This is the only operating
mode that provides the
load with continuously
processed and backed­up power: and in the
majority of installations
can be considered as
the ‘normal’ operating
mode.

In this mode, the input
mains AC supply is
converted to DC by the
rectifier which then
charges the battery and
provides the operating power for the inverter.

The inverter converts the DC produced by the rectifier back to an AC power source which is then connected to the load via
the inverter output contactor. The inverter frequency is synchronised to the bypass supply provided the bypass frequency
remains within preset limits. If these limits are exceeded, or if the bypass supply fails altogether, the inverter frequency
control reverts to a free-running oscillator which produces a constant 50Hz or 60Hz UPS output.

Load on battery

If the mains supply fails,
the rectifier shuts down
and the battery provides
the DC power source for
the inverter. The battery
voltage is regulated by
the booster circuit to
ensure the inverter
receives a suitable DC
input as the battery
discharges. On the
module control panel the
BATTERY LED will flash
green to indicate that it is
on load.

In the case of a dual feed input – if the bypass supply is still live when the input mains supply fails, the inverter frequency

remains synchronised to the bypass mains provided it is within its preset limits.

In the case of a single feed input – the bypass supply will fail at the same time as the input mains supply and the inverter

frequency control reverts to its free-running oscillator and will provide a constant 50Hz or 60Hz UPS output.

Battery discharge operation

When the battery is placed on load, and begins to discharge, the BATTERY mimic LED flashes green on the module
control panel accompanied by an audible alarm. The LED continues flashing green until the remaining autonomy time falls

RECTIFIER

BATTERY

INVERTER

STATIC

SWITCH

BOOSTER /

CHARGER

INV. Output

Contactor

Bypass Mains

UPS MODULE

Static bypass line

UPS Input Mains

UPS Output
to critical load

Figure 2.4 Load on inverter

RECTIFIER

BATTERY

INVERTER

STATIC

SWITCH

BOOSTER /

CHARGER

INV. Output

Contactor

Bypass Mains

UPS MODULE

Static bypass line

UPS Input Mains

UPS Output
to critical load

Figure 2.5 Load on battery

2: General Description

8 TS_619_00 PW9000DPA S2 User Manual 13/3/17

to three minutes, whereupon it begins flashing red. This allows the operator to gauge the remaining autonomy time and,
where necessary, shut down the load in an orderly manner (e.g. save data) before the battery is fully discharged. Various
options are available to automate the load shut down process and if an automated data protection application is installed it
usually begins its automatic shut down routine at this point.

The initial audible alarm can be cancelled but it will reappear when the battery voltage falls to its LOW BATTERY alarm
threshold, whereupon the audible alarm sounds once again to warn the operator that the battery is nearing its end-of­discharge.

Eventually, the BATTERY LED changes to solid red when the battery reaches its fully discharged voltage, and the UPS will
attempt to transfer the load to the bypass supply if the supply is present.

Load on bypass

In the ‘load on bypass’
mode the static switch
connects the load to the
unprotected static
bypass line.

This mode can be
selected manually (see
‘ECO Mode’ below) or
entered as the result of a
UPS fault (or overload)
condition which transfers
the load to bypass
because the inverter is
unable to support it.

Depending on the reason for entering the ‘load on bypass’ mode, the rectifier and charger sections might be turned off
entirely or remain operational and continue to provide battery charging (as shown above). Similarly, the inverter may have
been manually turned OFF or shutdown due to a fault, and the INVERTER LED on the module control panel may be either
OFF or solid RED.

Module OFF (Maintenance bypass)

When the UPS module
is turned OFF, all of its
internal power blocks
are effectively shut down
but the module input
power terminals remain
live unless the UPS
input/bypass mains are
externally isolated.

The maintenance
bypass switch (IA-1) can
be closed to maintain the
load supply, but in a
single UPS cabinet
installation this requires
the bypass mains supply
to remain live and
thereby prevents the bypass supply from being externally isolated.

Only one maintenance bypass switch is fitted per UPS cabinet and if the cabinet contains several modules (DPA-150,
DPA-250) the maintenance bypass switch (IA-1) bypass them all.

When operating a multi-cabinet system, the internal cabinet maintenance bypass switch (IA-1) should not be used, and an
external maintenance bypass installation that wraps-around the complete multi-cabinet system is required – usually
installed in a dedicated maintenance bypass cabinet, or wall-mounted as described in paragraph 3.4.2.

RECTIFIER

BATTERY

INVERTER

STATIC

SWITCH

BOOSTER /

CHARGER

INV. Output

Contactor

Bypass Mains

UPS MODULE

Static bypass line

UPS Input Mains

UPS Output
to critical load

Figure 2.6 Load on bypass

RECTIFIER

BATTERY

INVERTER

BOOSTER /

CHARGER

INV. Output

Contactor

Bypass Mains

UPS MODULE

Static bypass line

UPS Input Mains

UPS Output
to critical load

IA-1

Maintenance bypass line

STATIC

SWITCH

Figure 2.7 Module OFF (Load on maintenance bypass)

TS_619_00 PW9000DPA S2 User Manual 13/3/17 9

2: General Description

2.3.3 UPS System operating modes

Section 2.3.2 described the operating modes for the individual UPS modules: but UPS systems are also categorised
according to the way in which they operate at a ‘system’ level, and are typically described as being either an ‘on-line’, or
‘off-line’ (‘line interactive’) system.

The PW9000DPA S2 can be operated in either of these categories.

ON-LINE UPS system

An ‘on-line’ system provides the highest degree of load protection, especially if the utility mains supply suffers a
disturbance or complete failure, and we always recommended this mode of operation if the critical load will not tolerate
even a very brief supply interruption – e.g. in the case of a computer system.

When the PW9000DPA S2 is used as an ‘on-line’ system, the UPS modules normally operate in their ‘on inverter’ mode
(Figure 2.4), and switch to the ‘on battery’ mode if the input mains supply fails (Figure 2.5). The changeover to battery
operation is totally transparent at the UPS output and an audible and visual alarm warns the operator that the battery is
discharging to enable any intervention to be taken to protect the load integrity.

The UPS then continues to provide its rated output until the battery discharges to a low cut-off point at which time the UPS
attempts to switch to its ‘on bypass’ mode. If the bypass is unavailable the UPS shuts down in a controlled manner.

It is usual, especially in larger installations, to provide the UPS with an alternative input supply from a standby generator
which starts automatically following a UPS input mains failure; and where this is implemented the batteries only discharge
for a short period, until the generator comes on-line. This not only avoids the UPS shutting down due to a fully discharged
battery but also helps maximise the battery life cycle.

If the UPS experiences an internal fault during ‘on-line’ operation, the inverter turns off and the static switch transfers the
load to bypass mains automatically and without interruption – provided the inverter is synchronised to the bypass. If there
is an output overload, the inverter can supply the overload for a limited time, depending on its severity, and if the permitted
time is exceeded the load transfers to bypass. The additional power available from the bypass supply will attempt to clear
the overload but if it persists it will ultimately rupture the bypass mains supply fuses. If the overload condition clears while
operating on bypass it re-transfers the load to the inverter and the UPS returns to its normal ‘on-line’ mode of operation.

OFF-LINE (On stand-by) UPS system operation

When the PW9000DPA S2 is used as an ‘off-line’ system, the UPS modules are normally operated in their ‘on bypass’
mode (Figure 2.6) with the load supplied via the static bypass line. However the rectifier and battery charger are still
powered up and maintain battery charging, and the inverter section is turned on and operating on standby.

Operating in this mode is slightly more energy efficient than operating in the ‘on-line’ mode due to the reduced rectifier and
inverter losses during normal system operation; and it is sometimes referred to as the “ECO” (economy) mode. However,
this mode is recommended only if the connected load equipment can tolerate power interruptions of up to 3~5 ms during
the transfer period.

If the bypass supply fails, the inverter is immediately brought on line and the load is transferred from the bypass line to the
inverter within 3 to 5 milliseconds. If the UPS bypass mains and input mains are connected to separate sources (dual
feed) and the input mains is still live when the load is transferred, the UPS modules will operate in their ‘on inverter’ mode
(Figure 2.4). However, if the input/bypass mains supplies are c

onnected to a common feed, or the input mains is

unavailable in a dual feed system, the modules immediately revert to the ‘on battery’ mode (Figure 2.5).

When the bypass supply returns to normal, the load re-transfers to the static bypass line (without a break) and the inverter
returns to its standby operation.

Note: if the bypass is unavailable it is unable to take over the load supply if the inverter fails, or assist the inverter han dle
an output overload. It is therefore important that the cause of the load transfer from bypass to inverter is quickly rectified.

WARNING: The ON-LINE mode should always be used for critical load protection.

2: General Description

10 TS_619_00 PW9000DPA S2 User Manual 13/3/17

2.3.4 Parallel system operation

All the modules fitted in a UPS cabinet inherently operate as a parallel system as their outputs are connected in parallel at
the cabinet’s output terminals. The electronic control system built into each module ensures that:

• The modules are always frequency-synchronised to each other – and to the bypass mains (when present).

• The modules equally share the load current.

• The modules’ load transfer operation is synchronised such they ALL transfer their output between inverter and
bypass simultaneously when commanded from any one module.

The PW9000DPA S2 UPS system can be expanded by connecting up to six PW9000DPA S2 UPS cabinets in parallel;
and when two or more cabinets are connected in this way, all the UPS modules within them are effectively paralleled
together. For example: a maximum system capacity is obtained by connecting together six DPA-250 cabinets, each fully
populated with DPA-50 modules, which results in a total of thirty (50kVA) modules operating in parallel to provide a system
capacity of 1500kVA.

System expansion

Some UPS applications present a low initial power requirement which increases over time as the application grows; and it
is therefore essential that the installed UPS system can be expanded to meet the growing demand without compromising
the existing load. This requirement is well met with the ‘hot swappable’ feature of the PW9000DPA S2 UPS modules,
whereby an additional module can be inserted into a vacant slot in an existing cabinet without disturbing the load.

Note: If the expansion requires an additional cabinet the system will have to be shut down while the cabinet is installed.

‘Capacity’ versus ‘redundant module’ system

A parallel UPS system can be operated as either a ‘capacity’ or ‘redundant’ module system.

A ‘capacity’ system is rated such that ALL the UPS modules are required to furnish the specified full load power and the
loss of one module will automatically transfer the load to the bypass supply.

In a ‘redundant-module’ system, the system contains at least one UPS module over and above that required to supply the
full load and it is possible to lose a module without transferring the load to the bypass supply or in any way disrupt the UPS
output. A system operating with a redundant module is inherently the most reliable.

A parallel system operating with one redundant module is known as an ‘N+1’ system.

Parallel control bus

All the UPS modules within a cabinet, and between cabinets, are connected to a parallel control bus which carries several
control signals used for frequency synchronisation, load sharing etc. Each UPS module can electronically compare its own
frequency and output current with that of its neighbouring module and make any necessary fine adjustments to its control
logic to achieve balanced conditions across the system.

The parallel control logic observes one UPS module as being the ‘master’ and the others as ‘slaves’. However if the
‘master’ module goes faulty at any time the next module in the chain (a former ‘slave’) will immediately take over the role
of ‘master’ and the former ‘master’ module will turn off. The ‘master/slave’ configuration is set during commissioning.

During commissioning, the UPS modules are also assigned a numerical ID according to their position in the cabinet, with
the bottom module being given the lowest number. Figure 2.8 shows two DPA-250 cabinets with the modules in cabinet 1
assigned an ID of ‘P01’ to ‘P05’ and those in cabinet 2 an ID of ‘P06’ to ‘P10’ (‘P’ indicates that the modules are part of a
Parallel system). The module ID is used by the control and monitoring logic.

Key Point: When planning a multi-cabinet system, it is not necessary to fully populate one cabinet with UPS
modules before installing the next cabinet. For example, if it is known at the outset that a 200kVA initial load
requirement is likely to increase to 400kVA, it makes sense to install and cable-up two DPA-250 cabinets and
distribute the initial requirement of four UPS modules between them.

TS_619_00 PW9000DPA S2 User Manual 13/3/17 11

2: General Description

Figure 2.8 PW9000DPA S2 – Parallel cabinet system

2.4 PW9000DPA S2 User controls

The following illustrations show the location of the PW9000DPA S2 power switches and fused isolators that are used
when operating the equipment. The module control panel (one per UPS module) is described in paragraph 2.6.

STATIC

SWITCH

INVERTERRECTIFIER

Parallel Control Logic

UPS Module P06

CHARGER

STATIC

SWITCH

INVERTERRECTIFIER

Parallel Control Logic

UPS Module P07

CHARGER

Parallel Control Logic

UPS Module P08

Parallel Control Logic

UPS Module P09

Parallel Control Logic

UPS Module P10

UPS CABINET 2

STATIC

SWITCH

INVERTERRECTIFIER

Parallel Control Logic

UPS Module P01

CHARGER

STATIC

SWITCH

INVERTERRECTIFIER

Parallel Control Logic

UPS Module P02

CHARGER

Parallel Control Logic

UPS Module P03

Parallel Control Logic

UPS Module P04

Parallel Control Logic

UPS Module P05

UPS CABINET 1

Parallel Adapter Board

To JD5 in UPS CABINET 3

JD5 JD6

ParallelAdapter Board

JD5 JD6

2: General Description

12 TS_619_00 PW9000DPA S2 User Manual 13/3/17

2.4.1 DPA-50 Component identification

Figure 2.9 DPA-50 Cabinet details

Battery trays

UPS Customer Interface connections
(described in the Options chapter).

[F4] Battery fuse

[IA2] Parallel Isolator

[IA1] Maintenance Bypass Isolator

UPS Module

JD1 Smart Port – RS232 (Sub-D9P)
JD7 Module control panel connector

RECTIFIER

BATTERY

EXTERNAL

BATTERY
CABINET

INVERTER

STATIC

SWITCH

BOOSTER /

CHARGER

Bypass

Contactor

Inv. Output

Contactor

Input

Contactor

Bypass Mains

IA-2

IA-1

F4

F1

F2

F3

UPS MODULE

UPS CABINET

Static bypass line

Maintenance bypass line

UPS Input Mains

UPS Output
to critical load

TS_619_00 PW9000DPA S2 User Manual 13/3/17 13

2: General Description

2.4.2 DPA-150 Component identification

Up to three UPS modules can be fitted, with the lower-most module identified as module 1.

The battery fuses are identified F4 to F6. F4 is associated with module 1, F5 with module 2 and F6 with module 3.

The parallel isolator switches (IA2) are labelled to identify their associated UPS module – e.g. IA2-2 pertains to module 2.

Figure 2.10 DPA-150 Cabinet details

Battery trays

UPS Customer Interface connections
(described in the Options chapter).

Parallel Isolator (1 per module)

[IA1] Maintenance Bypass Isolator

UPS Module P03

UPS Module P02

UPS Module P01

[IA2-1] [IA2-2] [IA2-3]

Battery fuse (1 per module)

[F4] [F5] [F6]

JD1 Smart Port – RS232 (Sub-D9P)
JD7 Module control panel connector

JD1 Smart Port – RS232 (Sub-D9P)
JD7 Control Panel connector

JD1 Smart Port – RS232 (Sub-D9P)
JD7 Control Panel connector