How We Deliver Power to You
Electricity is produced at power stations across the island, and delivered to our customers via a transmission and distribution network. Energy delivery involves a complex infrastructure, which includes: switchyards, substations, high voltage transmission lines, transformers, and distribution lines. Here are some definitions that you will find useful:
The electricity from the plants flows through metal conduction to a switchyard, which controls the flow of the electricity into the voltage transmission lines.
Transmission lines efficiently carry high-voltage electricity over long distances to substations.
At the substation, voltage is transformed from high to low, or the reverse, using transformers.
• Electricity distribution is the final stage in the delivery (before retail) of electricity to end users. A distribution system’s network carries electricity from the transmission system and delivers it to consumers.
The pole-mounted transformer reduces the voltage to a level that can be used in homes and businesses.
Residential customers consume power at the lowest voltage of electricity.
A business usually uses power at a higher voltage than a residence.
Power Generation Technologies
The steam generating units are the foundation units of our generating system, and are often referred to as the “base load” units. The process of electricity generation via the steam generating units is as follows:Heavy-duty oil is taken from a bulk storage tank (typically 25,000 barrel capacity) and is supplied to a fuel pumping and heating set. At the pumping and heating set this fuel oil is heated to approximately 220°F in order to reduce its viscosity, and to enable it to burn easily. The heated fuel oil is pumped under pressure (approximately 250 psig) to the furnace of a steam generator (boiler) where it mixes with a large volume of air and is burnt. After combustion takes place a large volume of high temperature gas (approximately 2400°F) is released. The heat, which is now available, is transferred to very high purity de-mineralized water contained in hundreds of tubes, which form part of the construction of the boiler. The water is converted into high temperature and high-pressure steam through different stages of boiling and super heating within the confines of the boiler tubes. This high pressure, high temperature steam then passes through a main steam pipe to the turbine. (The turbine is a device used to convert the heat energy contained in the high pressure temperature steam into mechanical energy.) The turbine shaft is connected to the rotor of an electric generator and causes this rotor to rotate at high speeds. Coils of wire (field windings) are embedded into the rotor of the generator through which direct electrical current is allowed to flow. As this current flows, a strong magnetic field is formed. This rotating magnetic field is allowed to interact with another set of wires (stator coil), which are in this case stationary. It is this interaction of the magnetic field with the stationary wires that produces electricity.