Power substations are the most integral part of a power utilities' electric system. Substations make up the various electric systems - power generation, transmission, and distribution systems. Power substations consist of power transformers, voltage/potential transformers, current transformers, electrical bus, foundations/structures, circuit breakers, switches, outdoor cabinets, control house, fencing, etc.
Many design aspects and processes go into engineering and designing a power substation from the ground up. This discusses the basic steps performed in planning and implementing a new substation.
Designing substation ground mats is an important step in designing power substations. A proper grounding system is essential for human safety, especially during faulted conditions. For lower voltage panels and equipment, the NEC recommends maintaining a ground resistance of 25-ohms or less per NEC 250. With substations, the recommended ground grid resistance should be 5-ohms or less due to much higher voltages and increases in fault current, depending on substation size and voltage levels.
The main goal for a grounding system is to ensure that the path of least resistance for electrical current is not through personnel or equipment. A well-designed substation ground grid can uphold human safety for authorized personnel working in or around substations during faulted conditions. It is recommended to extend the substation ground grid outside the substation fencing for adequate protection.
Protection and Controls (P&C) engineering and design is extremely important in power grid protection and coordination especially with the use of intelligent electronic devices (IEDs). Proper P&C designs and coordination with protective relaying and IEDs is an essential part of electrical power engineering for protecting large expensive power equipment such as: generators, transformers, transmission lines (TLs), power circuit breakers, electrical bus, etc.
Arc Flash Analysis is extremely important in power systems and electric facilities (including any other facility that is comprised of major electrical components) especially for upholding the safety and well-being, including protecting electrical workers from electrical arc bursts and hazardous conditions. OSHA, NFPA, NEC, and others require arc flash studies to be performed with arc flash warning labels to be placed on the exterior of electrical equipment, cabinets, and panels indicating the proper PPE required for ensuring the safety of employees, contractors, and vendors. There are several software packages available that can aid the power professional in performing an arc flash analysis.
MCCs are most widely used in the utilities, manufacturing, industrial, and large commercial industries that operate machinery and motors. MCCs offer enormous flexibility across differing industries and are suitable for many applications, such as: utilities, communications, oil, gas, chemical, pulp, paper, water, waste, mining, metals, industrial production, and mass-production manufacturing. MCCs are used to house various power distribution equipment and controls such as: main distribution panels (MDPs), main circuit breakers (MCBs), protective relaying, transformers, load centers, panelboards, etc.