Power Engineers Window

  Study of Neutral Break Condition   Preamble In case of transmission system, there is situation when load (received) voltage is higher than supply (sending) voltage. This phenomenon is Ferranti Effect. This happens on Unloaded Long EHV line. But similar situation occurs in distribution system on Loaded Short LV line under neutral break condition.  There are two conditions of neutral break as under   A.     Conditions when neutral connection to ground is open as shown in the figure due to break between transformers neutral to earth connection.                                                                        Consumers continue to get normal phase and line voltage as usual. Effect of such isolation is on its ground fault protection and insulation system.   ...

  Loads Generally as common sense load means weight. It may be weight carried by human, animal or vehicle. Sometimes it refers to the quantum of work assigned to employee.   Teaching period is load for professor and syllabus is load on students. Load on structure may be gravitational force of mass resting on it or force due to thrust or pull like wind pressure as on electric conductor and support. All these may cause strain in various parts of the structure. Strain may be basic like compressive, tensile and shearing or complex like torsional and bending. But in any case structure reacts by inducing opposing force known as stress to counter balance the load. Stress is proportional to strain up to elastic limit and strain is proportional to the load till elastic limit. In any case stress can be equal to and opposite to load but not more than the load. Material cannot induce stress beyond elastic limit. In such case uncontrolled strain results in failure. Electric field int...

  Actual / Virtual Resistance / Conductance When electricity flow in the conductor, it experience obstruction. It is like biker facing difficulty while driving through crowded road. Difficulty level depends on the density of the crowd. But difficulty level may be less with the same crowd if road is wider. This phenomenon of obstruction to flow of current in conductor is a characteristic of the conductor material. This characteristic is material related depending on its atomic structure and is known as Resistivity or Specific Resistance and ρ (rho) as symbol. Actual resistance of the particular conductor depends on resistivity, length and cross section of the conductor. R = ρ × L / A Where            L = Length of the conductor A = Cross section area of conductor ρ = Resistivity of the conductor material. Relation with supply voltage and current is given by Ohm’s Law. Current I in the circuit = Applied Voltage / Resista...