Purna Dam Automation Project
The Purna Medium Project comprises of Dam across river Purna,a tributary of Tapi near village Vishorli in Chandur Bazar Taluka of Amravati District. The stored water is used for irrigation through the canal network and for domestic water supply through gravity main. The dam has central spillway with nine radial gates of size 12.00 x 8.00 m each. Project catchment area is hilly and lies in Maharashtra and Madhya Pradesh. Rainfall in the project area is in tune of 800-1000 mm. Irrigation cum power outlet is located at RD 300 on left flank. Two Gallery dewatering pumps are installed for dewatering leakages.
Earlier installed System:
Manual rainfall measurement
No communication means
Reservoir Level from gauges
Gate Measurement very crude methods
Manually Performed calculations based on historical data
Considering the scenario, Flood forecasting and Dam automation is a necessity.
Telemetry SCADA and Measurement system for Inflow Forecasting, Flood regulation, Water Distribution Management and Pump control for Purna Medium Project is designed, developed and implemented for monitoring Dam water levels, inflow, outflow, expected inflow, Spillway Gate positions, Rain gauge data, River gauge data, etc. The monitoring and control system is the tool for the inflow forecasting, flood regulation and water distribution.
Strategies for System Implementation:
The system is implemented for the control of spillway gates for flood regulation
The system continuously monitors rain gauge data & dam level, calculates inflow, outflow from spillway & expected inflow using inflow forecasting software module and operates spillway gates accordingly.
The system collects data from all field stations using VHF data communication network. System is being established for achieving precise monitoring, control and management of project.
It includes instrumentation, equipments and SCADA software for close-loop real-time monitoring and control of project. While designing the system due consideration is given for the utilization of existing equipments installed at site. The system is based on the proven techniques, ultra-modern technologies for hardware and software.
While designing the system emphasis is given to the physical, environmental and geographical conditions in the project area.
Measurement devices and communication network is the heart of the system and due consideration is given to harsh environmental conditions in the project area while selecting the equipment.
Operation of the System:
Rain Gauge Station
It collects the rainfall data, displays in proper format, stores data for 365 days at the interval of 1 hour and transmits the same to the control room at dam site through wireless VHF data communication network. The rain gauge stations are solar powered with sufficient battery backup.
Tipping Bucket type Rain Gauge isinterfaced with DASTU_RAIN, a microcontroller based data acquisition unit, which converts raw data into engineering units, displays on the 20 x 4 LCD display.
Automatic flood routing and monitoring system works on the principle of RAINFALL RUNOFF RELATION AND RATE OF CHAGE OF LEVEL AGAINST TIME. This system provides complete on-line real time monitoring of reservoir, catchment and down-stream status, automatically controls SPILLWAY RADIAL GATES using specially designed user friendly menu-driven software based on predefined conditions, received on-line data, along with manual override controlled by password security. The system also provides anticipatory control using rainfall data and rainfall run-off relationship developed for the project.
Computerized remote control system for Flood Regulation from dam utilizes the parameters / data received from the monitoring system. It controls the spillway gates in such a fashion that the flood passing through river will be moderated without affecting dam safety. While routing the flood all parameters like rainfall in the catchment area, likely inflow, travel time, levels in the dams on u/s and d/s, etc., will be taken into account. The Decision Support Software (DSS) automatically adjust the gate openings of spillway radial gates. The gate positions will be periodically modified on the basis of received / calculated data in close loop fashion.
The Decision Support Software operates the spillway gates taking into account gate operation schedule. While calculating the discharges reservoir operation schedule is also taken into account.
An individual auto/manual switch is provided for operation mode selection. In Auto mode computer system operates the gates automatically as per as per pre fed gate operation schedule or as per command given by the operator. In manual mode operator has to operate the gates by pressing the remote push buttons provided in control room or local Push buttons provided in gate control console (GCC) at motor end
SCADA application software running on IPC at Dam control room continuously monitors the following parameters
Water level in the reservoir and compares it with the level to be maintained as per the reservoir schedule.
Extent of gate opening using gate position scanner
Collects data from rain/river gauge stations
Calculates actual inflow using change in reservoir level, expected inflow based on the rainfall and provided rainfall run-off relationship.
Displays received/ calculated data on the screen along with the graphical representation of spillway gates.
Stores the status data logging system.
Calculates the time to reach MWL and FRL considering current rate of change of level.
Calculates discharge required to be let out and accordingly repositions the gates [extent of gate opening] taking into considerations, gate operation schedule and anticipatory inflow, downstream conditions etc.
Annunciates to the system operator in the event of abnormal conditions like heavy rainfall, heavy inflow, crossing of pre-set downstream constrains, failure of any gate, communication failure etc. High range hooter is installed at dam site to annunciate the public in near vicinity of the dam. Based on the severity of the condition, hooter duration is modified.
The data communication network for inflow forecasting and flood regulation is based on VHF wireless network. The frequency planning is made such that the field stations installed under the system forms an independent data network.
Remote Monitoring System
Remote Monitoring system for inflow forecasting and flood regulation is provided & Installed at Divisional Office. This system automatically collects data from the Master Control Station at Dam site after pre-programmed time interval or as and when requested.
The System hardware instrumentation can be grouped in the following categories-
The Measurement equipments / sensors
Power supply equipments
Data Acquisition units
Wireless Data Communication units
Outcomes and Resulted Benefits
Centralized monitoring & automated control of the project
Error free on line monitoring of level, rainfall, inflow & discharge.
User can have the data on his cellphone.
Remote monitoring from higher offices for immediate decision and action
Reduce communication delay
Reduce man made errors &negligence which may cause havoc.