Cascade Efficiency and Aggregated Technical and Commercial Losses (ATC)
- The primary function of transmission and distribution equipment is to transfer power economically and reliably from one location to another.
- Conductors in the form of wires and cables strung on towers and poles carry the high voltage A.C. current.
- A large number of copper or aluminium conductors are used to form the transmission path.
- The resistance of the long distance transmission conductors is to be minimized. Energy loss in transmission line is wasted in the form of I2R losses.
- Capacitors are used to correct power factor by causing the current to lead the voltage. When A.C. currents are kept with voltage operating efficiency of the system is maintained at a high level.
- Circuit interrupting devices are switches, relays, circuit breakers and fuses. Each of these devices is designed to carry and interrupt certain levels of current.
- Making and breaking the current carrying conductors in the transmission path with a minimum of arcing is one of the most important characteristics of this device.
- Relays sense abnormal voltages, currents and frequency and operate to protect the system.
- Transformers are placed at strategic locations throughout the system to minimize power losses in the transmission and distribution system.
- They are used to change the voltage level from low to high or from high to low.
- The power source to end user energy efficiency link is a key factor, which influences the energy input at the source of supply.
- If we consider, the electricity flow from generation to the user in terms of cascade energy efficiency. A typical cascade efficiency profile from generation to 11-33 kV user industry will be as follows.
The cascade efficiency in the T and D system from output of power plant to end user is
=0.995 x 0.99 x 0.975 x 0.96 x 0.995 x 0.95 = 0.87 = 87%