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Special Issue | October 2014 151
BARC NEWSLETTERFounder’s DayDEVELOPMENT OF MACHINERY PROTECTION SYSTEM
D.A. Roy, Prema Kumar Kavalan, Mohit Kalra, Sanjay K. Jain and GauravReactor Control Division
Abstract
A DSP based Machinery Protection System (MPS) has been designed and developed jointly by BARC and ECIL.
The system is designed to protect the rotating machines from catastrophic failures due to excessive vibration. The
system provides continuous, online monitoring of vibration and related signals. The system is manufactured by
ECIL and two units of MPS have been installed and commissioned in NTPC power plants for protection of Turbo
Generator Machinery.
Shri D.A. Roy is the recipient of the DAE Group AchievementAward for the year 2012
Introduction
Health of large rotating machinery gets reflected in the
vibration and other dynamic signals collected from the
rotating equipment and supporting structures. Using
this data, it is possible to detect impending trouble in
the machine so that preventive action can be taken
in time and catastrophic failures can be avoided. An
on-line vibration monitoring and protection system
thus plays an important role in ensuring safety and
economics of the plant.
With the aim to address the need for such an on-
line system having state-of-art features, indigenous
development of a Digital Signal Processor (DSP) based
Machinery Protection System (MPS) was initiated
by RCnD, BARC as a joint effort along with ECIL,
Hyderabad under an MOU between BARC and ECIL.
The main components of the system (Fig-1) are the
front-end instrumentation consisting of transducers
(for vibration, speed and related parameters) and
signal conditioning, DSP based data acquisition and
protection module and back-end PC-based monitoring
and configuration station. The main objective of the
system is to monitor vibration and other dynamic
signals to detect any deviation from normal levels and
to provide alarm and trip signals in case the deviations
are beyond certain set limits.
The Machinery Protection System (MPS)
acquires a number of dynamic input
signals (like vibration, displacement,
eccentricity etc.) and speed input signals
from field and on detecting signal levels
beyond certain limits it provides alert
signal to operator and generates contact
outputs to shutdown (trip) the machine.
The system can be configured to measure
the following parameters:Fig.-1: Machinery Protection System (MPS)
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CONTENTS
152 Special Issue | October 2014
BARC NEWSLETTERFounder’s Day1. Absolute Vibration
2. Relative Shaft Vibration
3. Absolute Shaft Vibration
4. Shaft Position
5. Shaft Eccentricity
6. Absolute Expansion
7. Relative expansion
Protection is achieved by generating contact output
to trip (shutdown) the machine when any of the
above measured parameter exceeds the set limit. It
sends relevant information on Ethernet for display
to operator on a PC based Engineering Console. The
Engineering Console also provides facility to configure
various input parameters and their trip settings.
System Architecture
The Machinery Protection System (MPS) consists of
an Embedded system and a PC-based Engineering
Console (EC), which are connected through Ethernet.
The embedded system is of modular construction
and is user configurable through the Engineering
Console. The system acquires various dynamic signals
like vibration signal, displacement signals etc. and if
any of these signals crosses the ALARM (alert) limit, it
generates a alarm contact output and if the measured
value crosses the TRIP (danger) limit then it generates a
trip contact output which is used to protect/shutdown
the machinery.
Apart from the protection function the embedded
system also sends the acquired data to the
Engineering Console for monitoring, analysis and
display. The engineering console is used to configure
the embedded system, to analyze the data received
from embedded system and also to display the data in
different formats.
Embedded System
The Embedded System consists of various hardware
modules performing signal conditioning, data
acquisition, signal processing and protection
functions. These modules are designed and fabricated
as standard 6U cards and installed in a 19” bin. The
Embedded System consists of following hardware
modules which are assembled as shown in Fig-2.
• MachineryProtectionModule(MPM)
• InputOutputModule(IOM)
• RelayOutputModule(ROM)
Fig. 2: Embedded system with Engineering Console
Machinery Protection Module (MPM) The MPM
acquires analog signals, processes the acquired inputs
using a DSP and if any parameter exceeds the set
alarm or trip limits, it generates signal for alarm or trip.
This module consists of DSP, Microcontroller, Memory,
communication controller and other peripherals. It can
process 4 Dynamic (Vibration) channels and 2 Speed
Channels. It performs digital filtering using DSP as well
as signal processing functions like integration and
rectification and provides signal parameters like peak,
RMS. It performs online diagnostics on hardware and
software and generates messages in case of fault. It
interfaces with the Input Output Module through
backplane mechanism.
The MPM sends the processed data and messages to
the Engineering Console through Ethernet and receives
configuration data from the Engineering Console
during system configuration. The module can be used
as standalone protection unit for small systems.
Input Output Module (IOM) forms the input output
interface of MPS. The inputs and outputs of the MPS
Special Issue | October 2014 153
BARC NEWSLETTERFounder’s Dayare terminated on the screw terminals provided
on the facia of IOM. This module provides signal
conditioning for various sensors. This module also
provides the power supplies to various transducers.
It can cater to 4 dynamic channels and two speed
channels. There is provision for online testing of the
channels. It interfaces to the MPM and generates
alert and trip signals for ROM. The MPM and IOM
modules are shown in Fig. 3.
driven by the open collector signals generated in IOM
and available in the back plane. These relay outputs
can be dynamically configured from the Engineering
Console.
The design and development of the above hardware
modules as per required standard and development
of complex embedded software residing in MPM was
entirely carried out in-house.
Engineering Console
A PC based Engineering Console (EC) is used for
configuring the MPS and it also acts as a display
station for MPS. It displays the data received from MPS
in different formats like tabular, bar graph, trend etc.
It also displays the alert/trip, diagnostic and various
system states in message and LED display format. It
also shows long term trend display of RMS parameters
of signals, real-time frequency spectrum, waterfall and
orbit plots (see Fig. 4)
System Acceptance Testing and Manufacture
After completion of the design and development of
the system, it was subjected to extensive testing at TSI
lab of ECIL. After successful completion of acceptance
testing, the system was taken up for manufacture
by ECIL as a product. ECIL has received an order for
supply of the system to 4 units of NTPC power station
at Kahalgaon.
Installation and Commissioning of MPS at NTPC
MPS was installed and commissioned at two units
(210 MWe each) of Kahalgaon Super Thermal
Power Station by a joint team of BARC and
ECIL engineers. Two MPS systems configured as
Turbo Supervisory Instrument (TSI) and Vibration
Monitoring System (VMS) were installed for each
unit. The systems provide online monitoring and
machine protection for the turbo-generator set
Fig. 3: MPM and IOM boards of MPS
Fig. 4: Various GUI screens of MPS on EC.
Relay Output Module (ROM) provides relay
outputs for alert and trip (danger) conditions. This
board consists of 16 relays and one pair of contacts of
each relay is available on the screw terminal mounted
on the facia of the board. The relays in ROM are
154 Special Issue | October 2014
BARC NEWSLETTERFounder’s Dayof the power plant. The TSI system monitors
following parameters
• AxialShift
• TurbineSpeed
• DifferentialExpansion
• CaseExpansion
• Eccentricity
• CVSMvalvePosition
The VMS provides monitoring and analysis of vibration
at various bearing locations. Fig. 5 shows the MPS
systems installed at NTPC, Kahalgaon.
term maintenance support. This indigenous
development is aimed at reducing the dependence on
imported systems.
Acknowledgement
The authors express thanks to Shri Y.S. Mayya, Head,
RCnD and Shri C.K. Pithawa, Director, E&I Group,
BARC for their encouragement and support for
this development. The authors are also thankful
to Shri R.V. Reddy, DGM, CAD, ECIL and his team
for their wholehearted support during development,
integration, testing and deployment of the system.
Fig. 5: MPS systems installed at NTPC, Kahalgaon.
Conclusion
With the above development, an indigenous, state-
of-art and user-configurable system is available to
meet the requirements of machinery protection in
various plants. The system is being manufactured
and marketed by ECIL who also provide long
References
1. Jain, Sanjay K, et al, Design Manual of Machinery
Protection System, Rev 0, Mumbai, Jan 2009.
2. Jain, Sanjay K, et al, “Machinery Protection
System”, BARC Newsletter, Jan-Feb 2013
issue.