Underneath the transformer a collection basin is provided. They contain small quantities of oil which may leak and catch fire.
Transformers are a fire hazard but not one that is usually too serious. Įach means for disconnecting motors and appliances should be legibly marked to indicate its purpose, unless located and arranged so the purpose is evident.Įach service, feeder, and branch circuit should be legibly marked to indicate its purpose.Įquipment should be properly labeled with information to do with the manufacturer, voltage, wattage, and other ratings.Parts of electrical equipment which, in ordinary operation, produces arcs, sparks, flames, or molten metal should be enclosed or separated and isolated from all combustible material. Īll splices and joints and the free ends of conductors should be covered with an insulating device suitable for the purpose.Ĭonsideration should be given to the heating effects of the electrical circuits.Īll equipment should be properly insulated.The following general guidance applies to the design and operation of electrical devices (single-line/ one-line diagrams are discussed in Chapter 1: Safety in Design): In principle, the same situation and adjustments characterise the phase co-ordinate load-flow analysis Several existing conventional (one-line diagram) load-flow programs already allow the generator terminal voltage magnitude to be unknown and to be adjusted according to the voltage value of a remote-controlled bus-bar. At generator bus-bars where a P| V| specification is given, the value of P is the total active power output of the machine and | V| can be either E a or V p or any other controlled bus-bar voltage.
By any of the usual load-flow techniques these equations can then be solved iteratively. To a first approximation the term y N0| V N| 2/ E * a can be neglected in comparison with the magnitude of the term Σ S * / E a *.įor each generator the machine admittance matrix Y abc can be added to the polyphase admittance matrix representing the network of lines, transformers and admittance loads. ( − y 1 − y 0 Y a b c − α 2 y 1 − y 0 − α y 1 − y 0 − y 1 − α y 1 − α 2 y 1 3 y 1 0 − y 0 − y 0 − y 0 0 ( 3 y 0 + y N 0 ) ( V p V q V r E a V N ) = ( I p I q I r Σ S * / E a * + y N 0 | V N | 2 / E * a 0 )
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