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.