power systems loss

PROBLEM:   A 230kV transmission line has impedance of 50 angle 78 ohms and a capacitive reactance of 1200ohms. It transmits the power of a base load plant. On a certain dry season the sending end power is 100MW at 235kV and 95% power factor continuously for a period of one month. If cost of generation is 1.3dollars per kW-hr, what is the cost of the line losses for the one month period? SOLUTION: In analyzing this problem, we assume a nominal pi equivalent circuit. Also, assume the sending voltage as the reference and with a lagging power factor.  Nominal pi equivalent circuit

PROBLEM: A 15MW, 132kV, 80% power factor three phase load is to be served by a transmission line having conductors whose resistance is 0.5ohm/km. if the losses on the line shall not exceed 4.5%, how long must this line be? SOLUTION: To better understand the problem,let us first draw the figure that the problem would like to emphasize.

PROBLEM:   A 10-km, three phase transmission line delivers power to a load rated 2000kW, 6.9kV and at 80% lagging power factor. The resistance and reactance of each line are 0.2 and 1.2 ohms per kilometer, respectively. What percentage of the power generated is lost in the transmission line? SOLUTION: Similar to the previous problem , we should first draw the figure for us to understand clearly what is required for us to solve.

PROBLEM:  A 3-kilometer, 336ACSR, 3-wire short transmission line has an impedance of 2 + j5 ohms per wire. At the receiving end, a balanced 3-phase load and capacitor bank draws 3000kVA, 0.71 power factor lagging and 600kVAR respectively at 8000 volts per phase to neutral. Determine the power loss of the transmission line. SOLUTION: The first thing that we should do in analyzing any problem is to illustrate our interpretation of the problem into a figure which will make us better understand what is needed.

This guide publication is a reference containing fundamental engineering guidelines and basic recommendations on structural and electrical aspects of transmission line design, as well as explanations and illustrations. The many cross-references and examples should be of great benefit to engineers performing design work for RUS borrower transmission lines. The guide should be particularly helpful to relatively inexperienced engineers beginning their careers in transmission line design.

The first systematic presentation of electricity market design-from the basics to the cutting edge. Unique in its breadth and depth. Using examples and focusing on fundamentals, it clarifies long misunderstood issues-such as why today’s markets are inherently unstable. The book reveals for the first time how uncoordinated regulatory and engineering policies cause boom-bust investment swings and provides guidance and tools for fixing broken markets. It also takes a provocative look at the operation of pools and power exchanges.

Losses in the transmission lines most especially in the overhead bare type of conductors does not only depends on the load it carries or the resistance it possesses. Although these are the major factors to consider, we can not deny the fact that the temperature also contributes a lot. Resistance of any metallic object tends to increase as temperature rises. As a result, we can say that line losses in transmission lines are directly proportional to the temperature.

Corona Loss Power lost due to corona process. On overhead power lines, this loss is expressed in watts per meter (W/m) or kilowatts per kilometer (kW/km). Corona A luminous discharge due to ionization of the air surrounding an electrode caused by a voltage gradient exceeding a certain critical value. Corona, Overhead Power Lines Corona occurring at the surfaces of power-line conductors and their fittings under the positive or negative polarity of the power-line voltage.

The objective of this IEEE standard entitled Standard Definition of Terms Relating to Corona and Field Effects of Overhead Power Lines is to obtain uniformity in the use of terms relating to the areas of corona and the electromagnetic environment of power lines. Its scope is to define the most widely used terms specific to or associated with overhead power-line corona and fields. Here, we are focus more on terms that are relevant to Power System's Loss topic like corona and electric fields that can influence the level of losses in a transmission line. For a complete access on the said standard, you can refer to the link below for the pdf copy.

The essential textbook for electrical engineering students and professionals-now in a valuable new edition. The increasing use of high-speed digital technology requires that all electrical engineers have a working knowledge of transmission lines. However, because of the introduction of computer engineering courses into already-crowded four-year undergraduate programs, the transmission line courses in many electrical engineering programs have been relegated to a senior technical elective, if offered at all.

IEEE Std 524 of 2003 entitled IEEE Guide to the Installation of Overhead Transmission Line Conductors’ scope is focused in providing general recommendations in the selection of tools, equipments and methods that have been found to be practical for the stringing of overhead groundwires and overhead transmission line conductors. The standard also provides a comprehensive list of definitions for equipment and tools used in stringing and for stringing terms commonly employed.

Here in lesson 5, we will further understand the load flow module of ETAP. Load flow analysis is very helpful not only in determining the voltage and power flow but most especially through this we will be able to compute for line loss in transmission lines. ETAP is very effective in simulating the transmission and sub-transmission lines but it has a slight disadvantage if you would like to run a distribution line analysis.

The following links are some of my collected references which tackles losses in the transmission lines. This can be a good source for additional knowledge regarding our quest to better understand the nature of losses in every power system. This is for you to have no hard time searching the net.

How to compute for the losses in transmission lines? Losses in the transmission lines can be determined less complicated compared to transformers and  distribution systems . The basic computation of it usually surrounds to the fundamentals of ohm's law . Due to the simplicity of the transmission line configuration, solving for its line losses requires no advance knowledge in any electrical principles. However, there are also portion of these line losses that better understanding is necessary. 

System Voltages in Transmission Lines Table shown is the standard system voltages from ANSI standards C84 and C92.2 According to ANSI standards C84 and C92.2, system voltages are recommend to be within the table shown below. 345kV, 500kV and 765kV are considered to be in the Extra High Voltage (EHV) level. The choice of system voltage is in the decision of the utility. However, some points needs to be considered in choosing such, like voltage economics, conductors, distances, equipments, etc.

ETAP Lesson 5 : Working with Composite Networks in ETAP Software Here you will learn how to create networks that will simplify your one-line diagram. Learn the benefits of using Composite Networks.

Transmission System Requirements Listed below are the typical points to be considered before starting or even operating an Electrical Power System. These factors can be best categorized into three main points; Electrical Design, Mechanical Design & Structural Design.

 ETAP Lesson 4: Load Flow Example 1  Learn how to enter data into an existing one-line   diagram and run a load flow calculation.

ETAP Lesson 3 : Creating one-line diagram using ETAP software Creating one-line diagram in ETAP is very simple, the interface of this program is user firendly.

ETAP Lesson 2: Open an Existing Project using ETAP Software Learn to open files in ETAP using simple instructions that is windows based and easy to follow.

ETAP Lesson 1: Create New Project using ETAP Software This is where are software tutorial starts. ETAP is a highly advance power system simulation software used by many utilities worldwide. 

Structures in Transmission Lines Mechanical support for transmission lines serves a definite purpose in the system especially in overhead lines Transmission line structures obviously is a very important part in every overhead bulk power transmission lines. It's a support for ground faults protection, insulation, and of course for conductors. The variation of these overhead line structures almost depends on the imagination of the structural designer. Nevertheless, the most common classification of transmission line structures known are made up of either poles (concrete, wood or steel)  or lattices towers. Also, the shapes and sizes of the structures depends on the type of line. The reliability and stability of transmission most of the depends on the performance of these supports especially during odd weathers. Many factors are considered in designing a transmission line structure one of these is the mechanical and electrical requirements to be complied with. Not only that it s...

Transmission and Distribution Electrical Engineering This books is more of for the engineers and electrical  practitioners unlike with student texts that are more on theory .

CHECK THIS BOOK OUT! For further detailed study of Power Transmission Lines, you can download this book.

Losses occurs in every transmission line all because of its inherent property of electrical resistance. Electrical lines like ACSR cable possesses resistance which is considered to be a determining factor on knowing the extent of losses it could give to the system. That is why it vital for us to know the internal properties of these conductors for us to better understand its effect to system's loss. Tables shown below are some of the commonly used conductors in an electrical system. Conductor resistance is in per kilometer basis at 60 hz.

BUNDLED CONDUCTORS IN TRANSMISSION LINE Bundling of conductors in a transmission line is a product of experts' ingenuity. In support to this post regarding bundled conductors, we will discuss here how bundling of conductors can affect the losses in the transmission lines. Bundling of conductors in the transmission lines helps lessen the effect of the two major phenomena the exist especially in voltage levels of 220kV and up namely; the CORONA effect and the SKIN effect .  Corona, also known as partial discharge, is a type of localized emission resulting from transient gaseous ionization in an insulation system when the voltage stress, i.e., voltage gradient, exceeds a critical value.   READ MORE >>> Skin Effect in AC circuit is the tendency of the current to crowd toward the outer surface. This results in a current density that is greater near the outer surface of the conductor.   READ MORE >>> Conductor bun...

In a network of electrical system, majority of the losses occurs in the lines particularly in the electrical conductors. Losses also varies in the kind of materials used to serve as a conductor whether it could be an aluminum, copper, gold, silver and so on. In the past, electric power were transmitted through the use mostly of copper conductors. Copper is rank among the most ideal metals for transmitting electricity due to its low resistivity also, of which it is second to silver. However, in the modern days, aluminum replaced copper as a main material for transmitting electricity simply because of the much lower cost and lighter weight of an aluminum conductor in contrast to a copper conductor with the same resistance. Another advantage of an aluminum is when compared to a copper with the same resistance, aluminum tends to have a larger diameter. It is an advantage because with a conductor with a relatively larger diameter the lines of electric flux originating on the conductor will ...

Since the beginning of time where overhead transmission lines were first made, significant evolution occurred with respect to its construction and standards. Several technical innovations were realized as time goes by, not only to the way it was constructed but most especially to the materials that were used. Many of these components possesses its own respective electrical characteristics like the conductors and the connectors used. Image courtesy of http://www.nationalgrid.com/uk/LandandDevelopment/DDC/devnearohl_final/appendix2/ Understanding losses in the transmission lines not only means directly solving for the said value but most of the time it is by considering the materials and equipments involved in the construction which by virtue of many is the most prevalent way of analysis anyone should make. The following are the most common overhead transmission line components: Structures for Support (Poles & Towers) Wires and Cables (phase conductors & OHG...

Before we dig deep into the principles of Transmission Line Losses, let us first review a brief history of the power transmission line particularly with Overhead Transmission Line. (courtesy of wikipedia ) The first transmission of electrical impulses over an extended distance was demonstrated on July 14, 1729 by the physicist Stephen Gray, in order to show that one can transfer electricity by that method. The demonstration used damp hemp cords suspended by silk threads (the low resistance of metallic conductors not being appreciated at the time). However the first practical use of overhead lines was in the context of telegraphy. By 1837 experimental commercial telegraph systems ran as far as 13 miles (20 km). Electric power transmission was accomplished in 1882 with the first high voltage transmission between Munich and Miesbach. 1891 saw the construction of the first three-phase alternating current overhead line on the occasion of the International Electricity Exhibition in Fr...

What is the use of power factor in power system? Power Factor is defined in the fundamentals of electrical engineering as the cosine of the phase angle between the voltage and the current. An inductive circuit is said to have a lagging power factor , and a capacitive circuit is said to have a leading power factor indicate, respectively, whether the current is lagging or leading the applied voltage. (Stevenson Jr.)

What is loss factor and how it is used in system's loss analysis? When a loss study is performed on a particular item of equipment, peak load conditions are often assumed in the first analysis. After peak load losses are determined, the cost of these losses is computed using the calculated demand cost of losses . After peak load losses are figured, the total energy dissipated in losses over a year must be determined.

What is load factor used for in power system? Load factor in electrical context is defined as the ratio between the Average Load of the electrical system to the Maximum Demand that it attained. This is factor is used to determine the level of difference between the average load to the peak load. Like the Demand Factor , Load factor is also expressed in percentage form.

What is demand factor and how it serves as a good indicator in eletric utilities? Demand factor in electrical context is defined simply as the ratio of the maximum demand attained and the total connected load . This factor is usually expressed in percent form which represents the level of the existing demand to the available capacity of the system.

Before we discuss on any of the previously stated factor, let us first define some important terms the we should be familiar with: LOAD GRAPH/CURVE - is a graphic record showing the power demands for every instant during a certain time interval. The area under the load curve is equal to the energy or kW-hr delivered to the particular load. CONNECTED LOAD - The connected load on any system or part of the system is the combined continuous rating of all the receiving apparatus on the consumer's premises that is connected to the system under consideration. DEMAND - it is the load usually expressed in kW, kVA averaged over a suitable and specified interval of time of short duration. MAXIMUM DEMAND or PEAK LOAD - is the greatest of all the demands that have occurred during a given period. It is measured according to specifications, over a prescribed time interval during a certain period such as a day, a month, a year. AVERAGE LOAD - it is defined as the average demand dur...

Factors for Load Behavior Analysis Load behavior affects the performance of the  system. Likewise, the losses also depends on this. Load profile of any electrical system is deemed not to be absolute,there are what we call the peaks and valleys. Due to the nature of electricity usage, the level of electricity demand varies significantly hour by hour, day by day, week by week , and so on. As a result, load analysis must also varies depending on the seasonality. As an example, suppose an ordinary household uses there lights from 6pm to 11pm, if we try to compare the level of power demand between time 7am and 7pm, a huge electricity demand difference can be observed. This is all because the demand differs from one time to another and it is just wise to know that analyzing load behavior must also be dynamic. Consequently, due to varying load levels, losses in the system also varies depending on the present level of electricity demand. Losses on electrical components decreases and ...

DMS BY TELVENT POWER SYSTEM SIMULATOR SOFTWARE What can DMS Telvent do as a computer simulator software for Power System? DMS Software is the 21st-century software system for performing all technical tasks in distribution utilities in an efficient and optimal way that fulfills all requirements of tenders across the world. This modern software tool enables distribution utility personnel to: Dynamically monitor and control distribution network, Achieve high-quality knowledge about their distribution network, Efficiently utilize, design and develop distribution facilities, Reduce losses and operation costs, Raise the profit (revenue) of the utility, Improve the quality and quantity of supply of electrical energy to consumers DMS Software provides tools for dynamic visualization, monitoring and control of electricity distribution network, together with wide set of power applications for operation analysis, planning and optimization. System is built on open standard solutions an...

ETAP is a Power System Simulation software which is a fully integrated AC and DC electrical power system analysis tool. Engineers use ETAP in thousands of companies and electric utilities worldwide in the design, analysis, maintenance, and operation of electrical power systems. The AC network includes the following ETAP modules: In addition to  Network Analysis  capabilities, ETAP offers several powerful analysis modules for Distribution Systems design. ETAP supports  balanced or unbalanced 3-phase, 2-phase and 1-phase systems for radial, looped or meshed network including per-phase voltage drop and power flow analysis, fault calculations,  Protective Device Coordination (ETAP Star) Software ,  Optimal Capacitor Placement Software ,  Optimal Load Flow Software , Reliability Assessment Analysis Software ,  Switching Sequence Management Software , and more. Distributions Systems Software Key Features Balanced and unbalanced load flow and voltage drop ...

SynerGEE can perform detailed load modeling and a host of useful analyses on radial, looped and mesh network systems comprised on multiple voltages and configurations. All analyses rest on the solid load-flow foundation that makes SynerGEE the most reliable distribution analysis tool available. Circuit analysis with robust and technologically-advanced tools can safeguard your system through enhanced network performance, extended asset life and increased profitability. GL offers a comprehensive collection of power system analysis tools to support your data needs, including custom application development and product implementation in enterprise systems and processes. GL's service offerings include Engineering studies Load forecasting Cable assessment Distribution model building and verification GIS integration Load modeling Reliability modeling Real time model integration READ MORE >>>

Due to the complexities of the power system network, manual computations and simulations are now considered to be impractical if not infeasible. In the dawn of the computer age, engineers had come up with many differents ways in reducing the burden of solving certain problems relating to the electrical power system. This has evolved into a very sophisticated tool which are use by many of the present generation. At present, many simulation softwares had been developed to help engineers in these tedious tasks. These simulation softwares are known to be able to do many electrical computations and simulations namely; load flow analysis, fault calculations, reliability study, switching optimization, capacitor installation, etc. Not only that it can solve and suggest certain options, softwares can also be able to help in energy loss computation and segregation. Analyzing power system's loss in an electric utility is not as easy as it may sounds. Many factors are necessary to come up w...

ADMINISTRATIVE LOSS What is an administrative loss? Widely accepted fact is that losses is just those technical and non-technical ones. However, some electric utilities shall we say electric cooperatives that includes Administrative loss. The Administrative Loss is the component of Distribution System Losses that accounts for the electric Energy used by the Distribution Utility in the proper operation of the Distribution System. This shall include the electric Energy consumption of connected essential electrical loads in the following facilities, subject to the approval by the country's regulatory commission. Distribution Substations; Offices of the Distribution Utility; Warehouses and Workshops of the Distribution Utility; Other essential electrical loads of the Distribution Utility. Administrative losses is simply the energy consumption of any infrastructure, substations, or anything that is deemed necessary for the operation of the utility. Administrative Loss Adm...

What are the different types of non-technica loss? The Non-Technical Loss is the component of Distribution System Losses that is   not related to the physical characteristics and functions of the electrical   System, and is caused primarily by human error, whether intentional or not.   Non-Technical Loss includes the electric Energy lost due to  pilferage tampering of meters and erroneous meter reading and/or billing. 

TECHNICAL LOSS BREAKDOWN How does technical loss being computed? We learned from our previous discussions that in every electric utility, the system's loss are typical categorized into two; Technical and Non-Technical loss. In addition to that, we will further try to integrate this types of losses.  The Technical Loss is the component of Utility's Distribution System Losses that is   inherent or natural in the electrical equipment, devices and conductors used in the   physical delivery of Electric Energy. It includes the Load and No-Load (or   Fixed) Losses in the following:   Sub-transmission Lines;   Substation  Power Transformers ;   Primary Distribution Lines;   Voltage Regulators ;   Capacitors;   Reactors;   Distribution Transformers;   Secondary Distribution Lines;   Service Drops; and   All other electrical equipment necessary for the operation of the   Distribution System.   ...