SINGLE LINE DIAGRAM (SLD) Or, ONE LINE （单线图(SLD)或者一行）.pdfVIP

SINGLE LINE DIAGRAM (SLD) Or, ONE LINE DIAGRAM The single-line diagram is the blueprint for electrical system analysis. It is the first step in preparing a critical response plan, allowing you to become thoroughly familiar with the electrical distribution system layout and design in your facility. WHY IT’S REQUIRED? Whether you have a new or existing facility, the single-line diagram is the vital roadmap for all future testing, service and maintenance activities. As such, the single-line diagram is like a balance sheet for your facility and provides a snapshot of your facility at a moment in time. It needs to change as your facility changes to ensure that your systems are adequately protected. To make all the changes documented in a common file, making the electrical system easily understandable for any technical person inside/outside of the factory. An up-to-date single-line diagram is vital for a variety of service activities including: • Short circuit calculations • Coordination studies • Load flow studies • Safety evaluation studies • All other engineering studies • Electrical safety procedures • Efficient maintenance WHAT SHOULD BE IN A SINGLE LINE DIAGRAM (SLD)? A typical package of single line diagram shall include: • Incoming lines showing voltage and size • Incoming main fuses, cutouts, switches, and main/tie breakers • Power transformers (rating, winding connection and grounding means) • Feeder breakers and fused switches rating and type. • Relays (function, use and type) • Current and / or potential transformers with size, type and ratio • Control transformers rating. • All main cable and wire runs with their associated isolating switches • All substations, including integral relays and main panels with total load of each feeder and each substation • Critical equipment voltage and