Maximum Demand Controller
Q. state the working principle and operation of APC and MID controller used in transmission and System.
- High – tension (HT) users have to pay a maximum demand charge in addition to the usual charge for the number of unit consumed.
- This charge is usually based on the highest amount of power used during some period say 30 min) during the metering mouth.
- The maximum demand charge often represents a large proportion of the total bill and may be based on only one isolated 30 minute episode of high power use.
- Considerable savings can be realized by controlling power use and turning off or reducing non-essential loads during such periods of high power use.
- Maximum Demand Controller (Refer Figure) is device designed to meet the need of industries conscious of the value of load management.
- Alarm is sounded when demand approaches a preset value. if corrective action is not taken, the controller switches off non essential load in logical sequence.
- The sequence is predetermined by user and is programmed jointly by users and supplier of device.
- The plant equipment selected for load management are stopped as per the desired load profile.
- Demand control scheme is implemented by using suitable control control contractor.
- Audio and visual annunciations could also be used.