1.1 Gross, net, operating and design head
Gross head:
- It is the total vertical distance between the inlet and outlet of the hydropower system.
Net head:
- It is the difference between the gross head and the hydraulic losses (due to friction, turbulence etc.)
Operating head:
- It is the head available to drive the turbine, which is the difference between the total head and the losses resulting from the operating condition of the turbine.
Design head:
- It is the head used to design the turbine, which must be greater than the operating head.
- It includes the operating head plus a safety margin.
1.2 Plant and installed capacity
Plant capacity:
- It is the total power generating capacity of plant with respect to available discharge head and efficiency.
Installed capacity:
- It is the economically feasible capacity of the plant.
- It is the maximum power that can be generated by all generator at normal head and full flow.
Power (P) = η⋅ρ⋅g⋅H⋅Q
Where,
P = Power (Watts)
η = Efficiency of the system (decimal form, typically 0.7–0.9)
ρ = Density of water (≈1000 kg/m³)
g = Acceleration due to gravity (9.81 m/s²)
H = Net head (meters) (height difference between intake and turbine)
Q = Flow rate (m³/s)
1.3 Energy flow diagram (related to FDC), firm and secondary power and energy
Energy flow diagram:
- Energy flow diagram in hydropower engineering represents the flow of energy generated by the hydropower system over time.
- This diagram is related to flow duration curve because the flow duration curve is used to estimate the amount of energy that can be generated over a certain period of time.
- It shows how much energy will be distributed among different components of the system.
Primary power (Firm Power):
- The net amount of power which is continuously available from a plant to consumer at any time.
Secondary power:
- The excess power available over the firm power.
- Not available at any time.
1.4 Economic consideration in HP system
- Economic consideration in hydropower system refers to the cost associated with the development, operation and maintenance of the system.
Marginal cost-benefit approach:
- It is an economic analysis that examine the cost and benefits of hydropower.
- It identifies the marginal cost of generating electricity and environmental and social impact of power generation.
- It considers long-term economic impact such as potential for increased employment, increased tax revenues, improved public service and improve quality of life.
- It helps to identify the most cost-effective ways to harness the power of hydropower.
Optimization approach:
- It is the process of finding the most economically viable solution to the problem of optimizing the use of hydropower resources.
- This involves optimizing the use of water, power and other resources to maximize the benefits to be gained from the use of hydropower while minimizing the cost and risk associated with it.
- It includes using the most efficient means of generating, consuming and storing energy and ensuring that all energy sources are used in the most sustainable manner.
1.5 Estimation of power and energy potential and its demand prediction method
- The estimation of the power and energy potential in hydropower engineering is based on the amount of water flow, the head of the water and the turbine efficiency.
- It is calculated by using equation:
Power = Energy/Time
Method of demand prediction:
a.Class wise consumption:
- Electricity is consumed at different rate by different people. Residental area will have different energy consumption than commercial area.
b.Historical trends:
- The past recorded data can be mathematically interpreted and hence future demand can be forecasted using regression analysis.
c.GDP:
- The data of GDP and per capita energy consumption of country are used to find the relationship between economic development and power consumption.
- It is used to find the energy demand for targeted economic development.
d.Mathematical formula:
- Incremental formula
P=Po(1+(R/100))n
Where,
P= Power demand after n year
Po= Power demand at present
R= Incremental rate of power demand
1.6 Load curve
- It is a graphical representation of power consumption with respect to time.
- It may be daily, weekly, monthly or annual.
- 1 unit = 1 KWhr
- Base load= Minimum power demand in given time duration
- Peak load= Maximum power demand in given time duration
- Average load= Average power consumption in defined time period
i.e Average load= (Area under curve/Total duration of time)
Load factor (LF):
- It is defined as the ratio of average load by peak load. i.e LF=Average load/Peak load
Utilization factor (UF):
- It is defined as the ratio of peak load by installed capacity. i.e UF=Peak load/Installed capacity
Diversity factor (DF):
- It is defined as the ratio of the sum of maximum demand to the maximum demand of entire system. i.e DF= Sum of maximum demand/Maximum demand of entire system
1.7 Power demand variation
- Power demand variation is the fluctuation of electrical power demand over time.
- This variation can be characterized by:-
a.Daily variation of power:
- Maximum demand in morning and evening.
- Less demand during office hours.
b. Weekly variation of power:
- More stable than daily variation.
- Weekends tends to have lower energy demand than weekdays.
c. Monthly variation of power:
- More demand during festival in different months.
d. Annual variation of power:
- Different season in year have different demand.
- During winter we require power for heating.
- During summer we use electricity for cooling.
1.8 Power grid
- It is a system of interconnected power plants, transmission lines and distribution networks that are used to deliver electricity from the power plants to homes and businesses.
- It is also responsible for ensuring electricity generated is used efficiently and safely.
Components of power grid system:
1. Dam:
- Used to store water and regulate the flow of water into the turbine.
2.Turbine:
- Used to convert the kinetic energy of water into electrical power.
3. Generator:
- Used to convert mechanical power generated by the turbine into electrical power.
4.Transmission line:
- Used to transport the electrical power generated by the generator to the consumers.
5.Control system:
- Used to regulate the flow of water and flow of electrical power in the system.
References:
- Hydropower Development: Engineering & Policy Perspectives – John S. Gulliver & Roger E. A. Arndt
- Renewable Energy Systems: Hydropower and Beyond – Godfrey Boyle