Case Study

Case Study on Canal Automation

Posted on Jan 19, 2015 by MSPL. .. 42 comments.

Nagarjuna Sagar Canal Automation

Background:

Nagarjuna Sagar Dam is the world's largest masonry dam. It was built on the Krishna River at Nagarjuna Sagar in between Guntur district of Andhra Pradesh state and Nalgonda district of Telangana state, India.

Government of Andhra Pradesh recognized that its agricultural productivity with respect to irrigation water usage is low, and the Canal Automation Project should be taken as a part of modernization of Irrigation Management System.

The canals in the project area are in a state of disrepair. Few of the water control gates are functioning, and there are many unauthorized off takes. Discharges from the canals are uncontrolled, and can exceed those required for crops. However, little water flows to the lower reaches of the distributor canals.

Critical part for any improvement in canal performance is control of water release to landowners. Ultimately, volumetric charging for water delivered will compel landowners to use water economically and effectively.

The World Bank consultant advised AP Government that once the canal automation system installed Water User Associations, Distributary Committees and the Employer can cooperate to ensure that water is available to meet the reasonable requirements of the farmers, and that, in times of scarcity, available water is equitably distributed.

Strategies for System Implementation:

The underpinning philosophy of the automation system is the adoption of upstream control method of canal control. A prerequisite of an upstream control system is a system of demand prediction.

This control requires substantial communication between the Control Centre Operator and WUA officers, for the determination and negotiation of WUA water requirements and to advise WUAs of the status of flows and alarm conditions within their areas. A dedicated operational voice communication system is provided for this purpose.

Canal automation is the system for automatic data collection at appropriate sites plus remote and/or automatic control of gates at some of these sites.

The canal automation concept provides for 19 gate sites with 30 gates that are to be automatically controlled to a flow or level set point (at main canal off-takes and at boundaries between Water User Associations), and flow measurement at a further 11 sites.

This Project relates to the Canal Automation of a pilot area in Blocks 11A to 14 of Nagarjuna Sagar Right Canal System, which have a combined area of approximately 20,766 hectares. Seven major canals serve the Pilot Project Area from the Nagarjuna Sagar Right Canal (NSRC). The automation system provides for flexible control of water to supply the design cropping patterns;

 

The range of control available is capable of handling existing and future cropping patterns; Single failures of field equipment will only affect water supply on the immediate vicinity, and this to the minimum possible;

The automation system includes comprehensive alarming facilities to advise the Control Centre Operators of exceptional situations, and that these alarms will be prioritized according to urgency of the response required;

All the automation and communication equipment are suitable for the climatic conditions prevailing in rural Andhra Pradesh; the automation system provides for flexible control of water to supply the design cropping patterns;

The range of control available is capable of handling existing and future cropping patterns; Single failures of field equipment will only affect water supply on the immediate vicinity, and this to the minimum possible;

The automation system is backed with Solar Power to accommodate a prolonged loss of power supply, both in the field and at the Control Centre. The physical design of the field equipment is such that security aspects are maximized.

Operation of the System:

SCADA Software and Its Configuration:

The canal automation pilot project system consist of a Control Centre at Vinukonda, controlled gate structures and monitoring points at various strategic sites along the Nagarjuna Sagar Right Canal and its off takes

There are 30 field sites, each with RTUs of varying sizes, connected to the Control Centre by means of VHF wireless data communication.

The individual gate structures are in voice contact with Control Centre via an engineer's handset using the new data communication network.

The SCADA System provides information storage and retrieval facilities. These facilities are in the form of a real time relational database management syste (RDBMS), plus special modules for historical archival and retrieval to VDU-based presentation displays.

The database management system provides facilities to retrieve, insert, delete or modify data. The system allows data definition through a data dictionary (including definition of ownership and data usage), and data validation through integrity checks.

The SCADA System includes a full graphic display system with a well-defined and consistent graphical user interface (GUI). All Operator interaction possible is using this facility.

The SCADA System automatically reports abnormal conditions, alarms and uncommented changes of state through a standardized alarm / event annunciation system.

The SCADA System has facilities for event/alarm logging, VDU trending, recording and screen copying.

The SCADA system is designed to provide an annual system availability of greater than 99.90% without the loss of one or more system functions. The communication system is designed to provide an annual system availability of greater than 99.95% without the loss of one or more system functions.

The SCADA Control System organized in a two-tier structure.

The lower level is based on microprocessor controlled remote terminal units (RTU's) which collect primary data from instruments, and voltage free contacts from field devices, perform data validity checks and pass this information to the Control Centre at Vinukonda. This level in return accepts control commands from the Control Centre and operates gates according to programmed control functions.

The upper level comprises the main computers installation at Vinukonda. This level is the Control Centre, and functions to communicate with the RTU's, to acquire and convert data to engineering units, to maintain the system database, and perform all interaction with the Operator via the workstation GUI interface. The Control Centre also performs calculations, alarm reporting, data and report logging, trending of measurements and historical archival of data, and is responsible for all application programmes used in the control of the NSRC canal.

Gate Control Systems:

The Installed system caters Automatic operation of Gates at designated 19 locations using solar power canal gate Actuators and measurement of flows at these locations

At these locations Automatic Local Gate Control system is provided and control operations can be performed locally as well as from Master control room.

Solar Powered Gate Actuators caters Automatic operation of Gates at designated 19 locations using solar power canal gate Actuators and measurement of flows at these locations

At these locations Automatic Local Gate Control system is provided and control operations can be performed locally as well as from Master control room.

 

Communication System is provided with the

    Dedicated voice and data networks

    Data network with 9600 bps full duplex communication

    Dedicated Interrupt based critical error transmission network

    WUA Voice communication network

    Duplicated Trans -Receivers at control center for Redundancy.