# IEEE 3002.2-2018 pdf free

**IEEE 3002.2**-2018 pdf free.IEEE Recommended Practice for Conducting Load-Flow Studies and Analysis of Industrial and Commercial Power Systems.

Because the parameters of the elements such as transmission and distribution lines, cables, and transformers are constant, the power system network impedance is for the most part fixed. However, the power flow problem often involves constant kVA loads, generators, and tap changers, which then means that the relationship between voltage and current changes depending on the type of load. The same holds true for the relationship between the real and reactive power consumption at a bus, or the generated real power and scheduled voltage magnitude at a generator bus. Thus, power flow calculation involves the solution of a set of equations which involve loads of constant impedance, constant power, and sometimes constant current type. This power flow calculation gives the electrical response of the power system to a particular set of loading and supply power output.

4. Analysis objectives

One of the most common computational procedures used in power system analysis is the load flow calculation.

The planning, design, and operation of power systems require such calculations to analyze the steady-state (quiescent) performance of the power system under various operating conditions and to study the effects of changes in equipment configuration. Typical results from steady-state load flow analysis include power flow in each branch circuits, source loading, voltage magnitude, phase angles, etec.

For some types of equipment (e.g.. photovoltaic solar arrays or wind farms), a time varying simulation, such as a time domain load flow, may be required in order to fully understand the behavior of the electrical system over a period of time. These time varying load flow solutions are performed using computer programs designed specifically for this purpose.

Analyzing the solution of this problem for numerous conditions helps ensure that the power system is designed to satisfy its performance criteria while incurring the most favorable investment and operation costs.

Also, load flow results are very valuable for setting the proper protective devices to avoid nuisance tripping and improve system reliability. In order to perform a load-flow study, full data must be provided about the studied system, including one-line diagram, parameters of transformers, cables and transmission lines, rated values of each equipment, and the real and reactive power for each load.

Modern systems may be complex and have many paths or branches over which power can flow. Such systerms form networks of series and parallel paths. Electric power flow in these networks divides among the branches until a balance is reached in accordance with Kirchhoff’s laws.

There are generally two types of computer load flow programs- those intended for ofie planning purposes, and those designed to operate in real-time, actively receiving input from the actual system. Most load flow planning studies use off-line software. On-line, or real-time load flows incorporate data input from the actual networks and can bridge the gap between static/ planning network model and the model used by those responsible for actual system operation. Computer programs are also available that provide integrated of-line and real-time solutions for“what if” predictive analysis. Such systems are able to integrate with existing plant Supervisory Control and Data Acquisition (SCADA) systems. Integrated real-time systems can therefore be used as planning and design tools as well as a dispatching tool for the operator. And an additional level of sophistication is possible using so-called“optimal power flow” modeling that applies constraints in the load flow solution to achieve objectives, such as minimum fuel cost, minimum power loss, flat voltage profile, etc.

For industrial and commercial power systems, the load flow problem involves balanced, steady-state operation. Hence a single-phase, positive sequence model of the power system is typically sufficient. Three- phase or unbalanced load flow analysis software is available, but is rarely needed in industrial power system applications.

A load flow calculation determines the state of the power system for a given load and generation distribution. It represents a steady-state condition as if that condition had been held fixed for some time. There are situations in industrial applications where the issues of interest involve how those steady-state conditions change over periods of minutes to hours as a consequence of changes in loading or generation; these applications can be adequately simulated using conventional load flow tools by means of a series of simulations reflecting the pertinent changes. However, this kind of study may also be accomplished by utilizing a time-domain load flow program. On the other hand, concerns about how systems respond in the cycles-to-seconds time frame, perhaps as a consequence of short-circuits or other disturbances, should be addressed using dynamic stability software. Power system dynamic stability is beyond the scope of this document.

In actuality, branch flows and bus voltages constantly fluctuate by small amounts because loads change constantly (e.g.. lights, motors, and other loads are turned on and off). Engineers responsible for analysis shall understand the switching pattern and its implications, and may choose to ignore this while calculating the steady-state effects on system equipment.IEEE 3002.2 pdf download.