How do you calculate a single line diagram?

Calculation Procedure in 8 steps

  1. Establish Base Voltage through the System.
  2. Calculate the Generator Reactance.
  3. Calculate the Transformer Reactance.
  4. Calculate the Transmission-Line Reactance.
  5. Calculate the Reactance of the Motors.
  6. Draw the Reactance Diagram.
  7. Calculate Operating Conditions of the Motors.

How do you calculate pu reactance?

1.0 per-unit reactance on primary side = 100/30 = 3.333 n 1.0 per-unit reactance on secondary side = 50/60 = 0.833 3 n Transformer reactance p.u. referred to primary side = 1.1/3.333 = 0.33 p.u. = 0.33 p.u.

How do you calculate unit system?

Following steps will lead you through the process.

  1. Step 1: Assume a system base. Assume a system wide S b a s e S_{base} Sbase of 100MVA.
  2. Step 2: Identify the voltage base. Voltage base in the system is determined by the transformer.
  3. Step 3: Calculate the base impedance.
  4. Step 4: Calculate the per unit impedance.

What is a single line diagram?

What is Single Line Diagram? The definition of a single-line diagram or SLD is an electrical diagram or drawing that represents the components of an electrical installation system represented by symbols, and describes how the components are related.

What is single line diagram of substation?

Single Line Diagram (SLD) The single line diagram (SLD) is the most basic of the set of diagrams that are used to document the electrical functionality of the substation. Its emphasis is on communicating the functions of the power equipment and the associated protection and control system.

What unit is PU?

The per unit (PU or P.U.) method of calculation is often used as an aid in the analysis of electrical systems that operate at different voltage levels. The determination of per unit values is not the end objective of a study. Rather determined per unit values serve to assist in the calculation of other system values.

What is PU current?

Answer: Pu stands for per unit and this will be used in single line diagram of power distribution and it is like a huge electrical circuit with no of components (generators, transformers, loads) with different ratings (in MVA and KV).

What is base kV?

KVLL = Base Voltage (Kilo Volts Line-to-Line) MVA3Ф = Base Power. ABASE = Base Amps. ZPU = Per Unit Impedance. ZPU GIVEN = Given Per Unit Impedance.

What is PU value?

Per unit system (pu) • The per unit value of any quantity is defined as the ration of the actual value of. quantity to its base value. • PU of any quantity = Actual value of quantity in any unit.

How do you write per unit?

Per Unit Calculation | Per Unit System Examples

  1. The per unit (PU or P.U.)
  2. The PU system of calculations was more prevalent in the past years.
  3. A PU value can readily be converted back to a voltage, power, or any other value as long as the base value is known.
  4. Per Unit = (Present value) ÷ (base value)

What is the purpose of using single line diagram?

This type of diagram is mostly used in an electrical power system. All the connections are shown as single lines, the multiple conductors of power circuits, and the control circuits are shown as single lines.

A single line can show all or part of a system. It is very versatile and comprehensive because it can depict very simple DC circuits, or a very complicated three-phase system. Learn To Interpret Single Line Diagram – SLD (on photo: An example of 66/6.6kV power substation single line diagram)

Why are electrical power grids most commonly represented in single line diagrams?

When analyzing power grids on the transmission or distribution scale, however, showing each and every conductor in electrical schematic form would make the system diagram needlessly complex. For this reason electrical power grids are most commonly represented in a single-line diagram format.

How many breakers are in a single line diagram?

Single line diagrams like in figure 2 are used to illustrate the layout of buses in a substation. The arrangement of figure two is called a “breaker and a half”. There are three breakers for every two connections of lines or transformers to the bus, i.e. 1 ½ breakers per termination.

How to interpret a single line voltage diagram?

When interpreting a single line diagram, you should always start at the top where the highest voltage is and work your way down to the lowest voltage. This helps to keep the voltages and their paths straight. To explain this easier, we have divided the single line into three sections.

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