Case Study

Case Study on Tank Monitoring System

Posted on Jan 15, 2015 by MSPL. .. 42 comments.

Nagpur Municipal Corporation Tank Monitoring Project

Background:

       Water supply to Nagpur City was drawn from three surface sources viz. Gorewada Tank, Kanhan river, and Pench canal.  As augmentation was not possible due to site conditions, surface water source from river Kanhan 15 km. away from city was considered as perennial source.

          Water is supplied to the city by Master Balancing Reservoirs at Seminary Hills (SH) & Govt. House (GH). From Seminary hills and Govt. house master balancing reservoirs water is supplied to other reservoirs. These two MBR's also supply water to its command area. There are 43 service reservoirs in the city at 31 locations. The existing storage capacity is 150.79 Ml which @ 32 % of the total supply.

Situation prior to Project Implementation:

  •     Lack of monitoring system for system Input output
  •     No accountability for water losses
  •     No measuring system for water
  •     Lack of water quality monitoring system
  •     No ESR level monitoring
  •     Lack of monitoring system for pump efficiency
  •     Lack of data recording & monitoring
  •     No energy monitoring
  •     No full proof system to handle water supply problems

     This scenario resulted in the need of proper water distribution system for City Water Supply.

Strategies for System Implementation:

Water distribution monitoring using the subsystem referred as water distribution management system WDMS has been implemented for the Nagpur Municipal Corporation by providing a central monitoring station located at NMC administrative head office at civil lines, Nagpur & local monitoring at each WTP and pumping location of entire water distribution & supply components. The intention was to measure, record and monitor the parameters like flow, level, pressure, residual chlorine of, pH, turbidity, kWh consumption, voltage, current, power factor etc. of existing and proposed WTPs and Pumping stations of Nagpur Water Supply for which necessary PLC, input & output signals, sensors and transmitters have been provided along with suitable Telemetry / monitoring system.

The system is implemented using three levels of information system at ESRs, GSRs & MBRs level & one level of monitoring system at central location.

First level consists of primary sensors such as pressure, level, flow, residual chlorine sensors etc. These field instruments which are located at various local stations will acquire each ESRs, GSRs, MBRs information and will communicate the information to the next level of information processing system using standard 4-20 mA current signal.

Second level consists of Analog/Discrete Input Module which will communicate with the central monitoring system with Telemetry system. The communication media shall be based on radio telemetry system.

Third level consists of Telemetry / monitoring software running on PC located at NMC head office. The system will communicate with all the existing and proposed ESRs, GSRs & MBRs on intermittent basis. During each communication Telemetry system will get status of different parameters from the above Input modules. The telemetry system will transfer information with main server located at NMC head office. Whenever required it should be possible to start communication with specific above Input modules. The whole system can be monitored and the operator can give the instructions to the local site through voice or SMS for taking corrective action from other end. This system consists of Remote Terminal Units at local stations where the various parameters are connected through the wire. These RTU's are polled sequentially and periodically by the central telemetry system and as per requirement it is stored / displayed, etc. In addition to that any alarming condition at local station is generated, is also informed immediately without waiting for sequential polling to the central telemetry system. This system is similar to SCADA except it does not control the equipment at remote site through RTU.

Fourth level consists of WDM software system which will run in typical client-server mode. Data acquired directly from plant using level one hardware as well as data acquired by operator data entry shall be used as centralized plant information data. MS SQL database shall be used for information storage. WDM software, which will consist of different modules offering desired functionalities as described in Section-4, will use this database for its functioning. For implementing this level of software Ethernet based LAN system shall be used. It will consist of one server PC & one client PC, which includes PC used by telemetry. Contractor shall provide required furniture for the PCs & server. It is under the scope of this contract to provide all required latest software, all other peripherals and licenses & the same shall be registered in the name of Nagpur Municipal Corporation.

Operation of the System:

Raw Water Source:

Water Level in the reservoir /River and Gate Status of the service gates in the intake tower at various levels will be measured. Service gates from the Central Control Room are controlled and monitored through Wireless data communication link in Auto Mode and remote operations of gates from the Control room will be provided with the "Remote /Local switch".

Water Treatment and Pumping Stations:

The proposed system will provide the control and monitoring of the Treatment plant including flow measurement, water quality parameter monitoring chemical dosing, pump control, pump efficiency monitoring, temperature & Vibration etc., Clarifloclator operations like operation of agitators, scraper bridge and de-slugging activities will be automatic and based on the sludge level in the clarifloculator.

Water quality parameters like pH, Conductivity, Turbidity, Dissolved Oxygen, Residual Chlorine will be measured in clear water stage and raw water.

Proposed system will provide automatic operations of filter beds & Actuators.

Flow measurement will be done on continuous basis on WTP outlet with the help of Ultrasonic flow meters on M.S pipeline with operation and full control of valves from Central Control Station.

Distribution Network:

After treatment, the pure water is pumped to and then conveyed by gravity up to booster pumping station from where it is pumped to  MBR/ESR at various locations of the city with various branch off takes on the main transmission line Monitoring of flow for various zonal nodes will also be taken into account.

Continuous monitoring and transmission of water level of Master balancing reservoirs and ESRs will be done..

Continuous monitoring and transmission of pressure and flow in the MBR outlet and full atomization for control of existing outlet valve of MBR will be done. System will provide continuous monitoring and transmission of pressure, chlorine & Flow at inlet of ESR/GSRs at various locations.

Water level of Master balancing reservoir will be continuously monitored. Automation of booster pumping Machinery will be done.  Inlet, outlet flow and pressure monitoring and full control on existing I/O valves of MBR and at some distribution point will get monitored continuously.

Control of existing Valves at the inlet and outlet of all the ESR's with continuous flow and pressure monitoring on Inlet and outlets of ESRs/GSRs will be done. Residual Chlorine at inlet of ESRs will get monitored.

Central Control Room and SCADA:

The Central control station will collect the data from source, Treatment plant, Pumping stations at various locations, ESRs' and GSRs at various locations, over the wireless data communication network and will be displayed on the work stations in user friendly GUI/ MMI.

The control commands for the pumping stations and treatment plant operations will be transmitted to the respective stations and action of actual control will be taken by the local RTU / PLC system at the remote station. After execution of the command and completing action, feedback will be transmitted to the Central Control Room (CCR)

Each zonal office will have monitoring software running on the PC, for remote monitoring of the system connected to the Main server at the CCR. These monitoring stations will have access to the data only and control actions can only be taken from the CCR only.

Communication System:

VHF/GSM/GPRS/VSAT Wireless Telemetry Data Communication will involve.

Site Survey and preparation of Communication network.

Procedure for Allotment of Frequency and License.

Erection of Communication masts / towers in case of VHF

Establishing network for Pumping Station & Booster Pumping Station locations ESR, GSR at Locations and Central Monitoring Center

Factors considered while designing network are Minimum tower Height, Minimum or no repeater stations, Maximum Reliability and Redundancy, Data security and reliability, Communication Interval, Remote   diagnosis and programming, ,Future provision for remote control of pump house Minimal Inventory.

Outcomes and Resulted Benefits:

Centralized Monitoring System for Nagpur water supply & Distribution system.

More Accountability & responsibility on NMC officials

Citizens can be able to know all the components of  water supply system

Improved management information system

Since data is available on internet, online monitoring can be possible

Zonal offices becomes more informative & responsible to the public

Helps to water related conflicts or misunderstanding among citizens specially during peak demand season summer

Alarm facility can lead to rapid attention to the problem

Deviation from the standard parameters can be monitored & rectified.