Load Flow Study

Load flow is also referred to as power flow; these terms may be interchangeably used in common. This is the name given to a network solution that predicts steady-state currents, voltages, and real and reactive power flows through every branch and bus in the system. Load-flow studies simulate operating conditions that cannot practically be experienced on the actual system because the system has not yet been built, because of the practical constraints of time, or because it would be unwise to expose the actual physical system to conditions that are potentially damaging. The end objective of the load-flow study is not always to arrive at hard, numerical performance parameters. Often the objective is to gain insight into how the system performs over a range of operating conditions. Power flows are an important part of power system operation and planning.

Objectives of Load flow study:

To find the equipment loadings
Steady state bus voltages, Real and Reactive power flows can be found
To find the optimum transformer tap settings
To find real and reactive power losses at every branch
To find the Voltage drop at each bus
To find whether requirement for either fixed or variable reactive power compensation
To find the performance under different operating conditions

Load flow study Execution:

Gathering all the required input data such as, Single line diagram, cable schedule, datasheet of all equipment, name plate details, Load details and Factory acceptance report (FAT)
Through modelling of the entire electrical network in ETAP simulation software
Creation of multiple scenarios including emergency condition to find the performance of the system in various conditions
Preparation of full report on the study including Recommendations if necessary

Uses of Load flow study Results:

To verify the operation of an electrical system under various load and generation conditions
To plan the future growth of both loads and generation
To determine the best possible economical operation
To establish initial conditions for stability studies
To help identify the need for additional capacitive or inductive VAR support, to maintain system voltages within acceptable limits

Reference Standards:

IEEE 399-1997 – IEEE Recommended Practice for Industrial and Commercial Power Systems Analysis
IEEE 3002.2-2018 – IEEE Recommended Practice for Conducting Load-Flow Studies and Analysis of Industrial and Commercial Power System