The daily electricity consumption of a factory is estimated to be 9,588 kWh, of which 9,508 kWh is consumed during the peak period of 7am to 11pm and 80 kWh is consumed during the off-peak period of 11pm to 7am. The daily maximum demand is 920 kW. The owner of the factory is considering the options of taking the electricity supply from the power company at low voltage (400 V) or at high tension (22,000 V). The prevailing electricity tariff is shown in Table 1. Table 1 Prevailing Electricity Tariff Low Tension Supplies, Non Domestic All units, C/kWh High Tension Small Supplies Contracted Capacity Charge $/kW/month Uncontracted Capacity Charge $/chargeable kW/month kWh charge, C/kWh Peak period (7:00am to 11:00pm) Off Peak period (11pm to 7:00am) Reactive power charge C/KVARh 29.9 11.66 17.49 27.51 15.56 0.63 The electricity charge at low voltage is levied on the consumer based on the total energy (kWh) consumed in the month. The electricity charge at high tension is levied on the consumer based on the following charges Contract Capacity Charge which is the demand capacity in kW requested by the consumer. Uncontracted Capacity Charge is the demand capacity in KW by which the maximum demand in kW exceeds the Contract Capacity. (i) (ii) (iii) Peak Period Charge is the monthly charge based on the energy (in KWh) of the installation during the peak period, 7:00am to 11:00pm in that month. Off-peak Period Charge is the monthly charge based on the energy (in kWh) of the installation during off-peak period, 11:00pm to 7:00am. (iv) (v) Reactive Power Charge is a monthly charge payable for the installation's excess kVArh consumption. The excess kVArh shall be the difference by which the installation's kVArh consumption drawn from the network in that month is greater than 62% of its kWh consumption drawn from the network in the same month. Based on the electricity tariff in Table 1 on page 1, calculate the monthly (30 days) electricity charge payable by the owner if the supply is at low voltage (400 V), and if the supply is at high tension (22,000 V). Assume that the power factor of electrical installation is 0.8 lagging. The requested contract capacity at 22,000 V is 900 kW. (17 Marks) (b) Besides the electricity charges, list four factors for the owner to consider when choosing to take the supply at 400 V or 22,000 V. (8 Marks)