- Project
Hydro-Thermal Co-ordination
- Client
Karnataka Power Transmission Corporation Ltd (KPTCL)
- Location
Karnataka, INDIA
Case Study
The System
Connection of Reservoirs and Power Plants
| Power Plants | Production Capacity |
|---|---|
| Hydroelectric Plants | 3,657 MW |
| Thermal Power | 4,520 MW |
| Liquid and Gas-Based Plants | 237 MW |
| Renewable Energy Sources | 3,228 MW |
| Captive Power Plants | Remaining Capacity |
Most power generation facilities are located in remote areas across the state. Hydro power accounts for about 33% of Karnataka’s total capacity. Major hydroelectric sources include:
| Hydro Power Plant | Production Capacity |
|---|---|
| Sharavathi River | 1,470 MW |
| Kali River | 1,255 MW |
| Varahi River | 469 MW |
| Almatti Dam on the Krishna River | 290 MW |
Karnataka’s transmission system is generally limited by stability and must operate within security constraints. The network includes:
- 39,300 circuit kilometres of transmission lines.
- 1,315 substations.
- An HVDC link of 1,450 km between Kolar and Talcher, capable of transferring 2,500 MW.
Process Flow
Challenge
In the past, long-term generation planning in Karnataka was based on intuitive analysis. The System Control Centre prepared generation schedules using past experience, which worked well under similar operating conditions. However, when input conditions or assumptions changed, the system became constrained and often operated in non-optimal ways.
As the power sector evolved from a centralized model to a more decentralized setup, Karnataka Power Transmission Corporation Ltd (KPTCL) recognized the importance of forecasting future water inflows. Accurate forecasts became essential for preparing both long-term and short-term schedules. This approach helps optimize water usage, reduce thermal generation costs, and ensure reliable system operation, while staying within defined constraints.
Solution
M/s ABB was the turnkey solution provider for KPTCL’s SCADA/EMS implementation. As part of the project, a Hydro-Thermal Coordination (HTC) software package was included. M/s ABB outsourced the supply and integration of the HTC system with its EMS, which included:
- Water inflow forecasting (MiWiF).
- Long-term Hydro-thermal scheduling (MiLTHTS).
- Short-term hydro-thermal scheduling (MiSTHTS) with unit commitment and economic dispatch.
- Optimal power flow.
The HTC package (MiEMS/HTC™) was supplied and installed by PRDC. Developed using advanced technologies, this system helps operators and water resource teams generate efficient long-term and short-term hydro-thermal schedules. It aims to optimize the use of hydro and generation resources while reducing the cost of thermal generation.
MiWiF™
Accurate and dependable stream flow forecasts are essential for effective reservoir operation, supporting both flood control and optimal hydropower generation. MiWiF™ plays a key role in this by modelling river connectivity and water routing as part of a water resource system.
MiWiF™ forecasts natural inflows to lakes, reservoirs, and river reaches using historical data and external factors. As inflow forecasting is a continuous and critical process for hydro-thermal scheduling, MiWiF™ provides detailed weekly and hourly inflow predictions for both long-term (MiLTHTS) and short-term (MiSTHTS) planning. These forecasts are based on real-time hydraulic conditions and defined thermal and hydro constraints.
To handle the uncertainty of weather conditions, MiWiF™ features an advanced, dynamic closed-loop system that continuously updates forecasts using real-time inflow data and external inputs to ensure high accuracy.
Long-term hydro scheduling focuses on optimizing water use by considering both current and future availability, as well as electricity and irrigation demands. Short-term hydro-thermal coordination uses data from both short-term inflow and long-term hydro-scheduling to determine water availability and usage limits.
Using this information, MiHTC integrates user-defined constraints into a single solution that meets present and future demand. Both MiLTHTS and MiHTC use Mixed Integer Linear Programming to handle user-defined constraints. MiHTC applies these constraints while generating optimized hydro and thermal unit schedules.
| Hydro Constraints | Thermal Constraints |
|---|---|
| Water balance equation based on connectivity of reservoirs & plants | Thermal Cost functions |
| Irrigation constraints | Fuel constraints |
| Travel time delay for discharges and spillages | Unit Minimum and maximum generation |
| Minimum and maximum storage volumes | Unit startup costs (Hot, Warm and Cold state) |
| Minimum and maximum discharge limits | Unit startup times (Hot, Warm and Cold state) |
| Minimum and maximum power capacity | Unit Ramp Up and Ramp Down rates |
| Unit power production for constant head operating plants | Unit commitment decisions |
| Unit power production for variable head operating plants | Unit start up and shut down decisions |
| Hydro unit commitment decisions | Unit Minimum Down and Minimum Up time |
| Hydro unit start up and shut down decisions | Forced units |
| Hydro unit startup costs if any | Must run units |
| Minimum Up and Minimum Down times | Present Unit status |
| Ramp Up and Ramp Down rates | Unit maintenance |
| Maximum Number of Start Ups during study period and during day | Crew Constraints |
| Unit Spinning reserve contribution | Unit Spinning reserve contribution |
| Crew constraints | Max number of Start Ups during study period & during day |
Perceived Benefits
With the implementation of the water inflow (MiWiF™) and hydro scheduling (MiLTHTS and MiSTHTS), system shows significant improvement in its ability to forecast future inflows and hydro and thermal schedules. This has direct and positive impact on the overall hydro-thermal coordination. KPTCL should be now able to plan operations over long-term and arrive at detailed generation schedule in the short-term perspective to meet physical and environmental constraints, maximize revenues and control financial risks inherent in market-based operation.
With the integration of MiWiF™ for inflow forecasting and MiLTHTS/MiSTHTS for hydro scheduling, the system has significantly improved its ability to predict future water inflows and optimize both hydro and thermal generation schedules. This enhancement directly strengthens overall hydro-thermal coordination.
KPTCL can now plan long-term operations more effectively and create detailed short-term generation schedules. This helps meet operational and environmental constraints, maximize revenue, and manage financial risks in a market-driven environment.
