power systems loss

POWER CABLE AS USED IN UNDERGROUND DISTRIBUTION SYSTEM How are conductor and materials for power cables being specified? Conductor material and insulation type will be specified. Restricting extensions of existing systems to a specific conductor material and insulation type in order to match an existing cable type is permitted only when a need has been established. Neutral cables, where required, will be installed with 600V  insulation unless concentric neutral cable is used. In duct lines, neutrals will be installed in the same conduit with associated phase cables. Conductor material. Since underground conductors are continuously supported, soft-drawn copper or aluminum alloy 5005 provides adequate strength. However, the selection of copper or aluminum will be justified based upon an analysis using life, environmental, and cost factors. The need for mechanical flexibility requires that conducts be stranded, and the NEC makes this mandatory for cables larger than No. 8 AWG instal...

UNDERGROUND DISTRIBUTION LINES USING POWER CABLE IN AN ELECTRIC DISTRIBUTION SYSTEM How are power cables being used in an electrical distribution system? Underground distribution lines have been a long known technology used by many electric utilities in delivering power to its customers. This set up can usually be found in highly urbanized areas where space for overhead lines can be scarce. Various pros and cons are known to be associated in using underground distribution lines in a power distribution system. Like any other construction which involves public or private area, distribution system using underground lines installation must at all times coordinate with the installation master plan of the city or with any private properties to avoid conflict with construction of future facilities. For easy access for inspection and maintenance, underground lines are normally installed adjacent to roadways in urban, housing, or industrial plant areas, but may be routed as required to meet ...

WAYS AND MEASURES IN PROTECTING DISTRIBUTION LINE CONDUCTORS FROM DAMAGES  What are the ways in protecting line from damages that occur in transmission and distribution lines? Gentle Handling of Cable - Careful handling in the field to avoid scratches, cuts or kinks in the conductor is desirable during the field operations of paying out, stringing, and tying or clipping in. Follow Sag-Tension Charts - Sagging conductors at tensions higher than recommended increases susceptibility to aeolian vibration. Sagging in at tensions lower than recommended reduces the probability of aeolian vibration but increases susceptibility to galloping. The Use of Armor Rods on Conductors - Armor Rods are intended for clamp supports, but they can also be used at tied supports. Armor rods are effective in sacrificing their surface to abrasion instead of the conductor’s outside surface. In addition, they provide protection against electrical burning of the conductor from flashovers. Armor rods d...

COMMON LINE DAMAGE IN A DISTRIBUTION SYSTEM FEEDER LINE   What are the common of line damages that occur in transmission and distribution lines?  The cause of damages to transmission and distribution lines can be attributed to many potential reasons. Conductors are one of the most exposed electric company asset to many unfortunate events. The cost of conductors is one of the major expenses in any overhead power line construction. It is the primary component in the flow of revenue for a utility and the component most exposed to hazards. With the introduction of aluminum conductor, the vulnerability to damage increased due to its easily abraded surface. The four types of motion occurring on overhead power lines are (1) aeolian vibration, (2) galloping, (3) sway oscillation and (4) unbalanced loading. Each is independent in cause and effect. Insulator and conductor damage can be classified into four main points; where lines are seldom inspected, the first indication of damage ...

CIRCUIT PROTECTION FOR DISTRIBUTION SYSTEM FEEDER LINE How an electric utility protects its distribution system line? An electric utility’s role in an electric power system does not only focus on the delivery of power to its customers. They also need to concentrate in the conservation of their assets in the network. Assets in the system like the transformers, wires, structures, etc., have an equivalent monetary value where the utility must always take care of. The ability of the electric distributor to minimize the damage during failure at the fastest time possible is very important since this means property loss can also be in the minimum. Relaying fundamentals is an important tool that protection engineers must possess in order to carefully analyse their own system. The most common form of distribution system feeder line protection which is also the most important is the overcurrent protection. Its basic application is mostly on substation protection and distribution feeder line p...

DISTRIBUTION SYSTEM MODELING AND ANALYSIS BOOK By William H. Kersting This is the first book dedicated to distribution systems that is truly modern, covers computer applications, and gives a thorough grounding in modeling and analysis techniques. Assuming a basic foundation in transformers, electric machines, transmission lines, and symmetrical components, it serves as both a text for upper-level electrical engineering studies and as an essential reference for practicing engineers. CHECK OUT THIS BOOK

SPATIAL ELECTRIC LOAD FORECASTING BOOK By H.Lee Willis Containing 12 new chapters, this second edition offers increased coverage of weather correction and normalization of forecasts, anticipation of redevelopment, determining the validity of announced developments, and minimizing risk from over- or under-planning. It provides specific examples and detailed explanations of key points to consider for both standard and unusual utility forecasting situations, information on new algorithms and concepts in forecasting, a review of forecasting pitfalls and mistakes, case studies depicting challenging forecast environments, and load models illustrating various types of demand. CHECK OUT THIS BOOK

POWER DISTRIBUTION PLANNING REFERENCE BOOK By H.Lee Willis Lee (fellow, Institute of Electrical and Electronics Engineers) has doubled the total content of this second edition of a reference book and tutorial guide for the planning of electric utility power delivery systems. In addition to two new chapters on reliability, material on reliability engineering. CHECK OUT THIS BOOK

ALUMINUM CONDUCTOR ADVANTAGES IN OVERHEAD DISTRIBUTION LINE SYSTEM What are the advantages of aluminium conductors for distribution line application?  It is a worldwide practice that when it comes to transmission and distribution line system application, aluminium conductors rank first as the most utilized type of conductor material for electrical applications. ACSR or Aluminum Conductor Steel Reinforced is one of the most popular types of conductor used by electric utilities worldwide. The reason for aluminium’s popularity in electrical lines application can be discussed in many aspects. Seven distinct characteristics are basically known why electrical engineers treat aluminium to be superior when it comes to distribution line application; conductivity, light weight, strength, workability, corrosion resistance, creep, and compatibility with insulation. Aluminum’s conductivity is known to be more than twice compared to that of a copper with the same weight. A pure aluminum condu...

 SAMPLE DISTRIBUTION SYSTEM LAYOUT USING SYNERGEE SIMULATION SOFTWARE Distribution system layout example using a simulation software Effective distribution line analysis requires complete considerations of all involved line equipment that exist in utility’s distribution system. Also, computing for utility’s distribution system’s loss is of the same importance since all electrical equipment connected to the system has its own loss contribution that depends on the reliability of the available information. The analysis of distribution system’s loss starts from the substation feeder all the way down to the customer’s service point. Due to the complexity of the distribution system, manual computation and analysis tends to be found impractical and time consuming for the part of the person analysing. Through the aid of modern computer simulation software, distribution loss computation became more easily available for monitoring and analysis. Furthermore, field assets like lines, sw...

How line reconductoring affects distribution line loss? Our basics in electrical study from the past taught us the relationship between conductor resistance and conductor size. We’ve learned that conductor resistance is inversely proportional to the cross-sectional area of the conductor and directly proportional to its length. This means that for a given same type of material, when the conductor’s cross-sectional area increases, its resistance will decrease proportionally. While if the conductor length increases, its total line resistance will also increase proportionally.

EVALUATION OF DISTRIBUTION SYSTEM LOSSES DUE TO LOAD UNBALANCE TECHNICAL PAPER A technical paper authored and completed by Luis F. Ochoa, Rade M. Ciric, A. Padilha-Feltrin, Gareth P. Harrison of UNESP – Universidade Estadual Paulista, Faculdade de Engenharia de Ilha Solteira - Ilha Solteira, Brazil University of the West of England - Bristol, UK ABSTRACT – Distribution network losses can vary significantly depending on the load unbalance. Here, an analysis of distribution system losses is presented that considers load unbalance and the effect of explicitly represented neutral wire. A general power flow algorithm for three-phase four-wire radial distribution networks, based on the current summation backward-forward technique is applied. Loss analysis results obtained from three-phase four-wire medium and low voltage test feeders with unbalanced load scenarios are presented and discussed considering: a) original phase and neutral wires resistances; and b) resistances obtained by per...

How phase load balancing affects losses in the distribution lines? The most efficient way for a three-phase line or even a V-phase system to operate is when the loading on each line is said to be balanced. As what we constantly say, distribution line loss is dependent mainly to the two main variables, the line resistance and the line current.

  How single-phase to three-phase conversion affects distribution line losses? Electric Utilities around the world typically uses three-phase system in distributing power. Three-phase system is said to be relatively more superior compared to using a single-phase . The idea of a three-phase power was first conceived by non other than the founder of Alternating Current electricity, Nikola Tesla .

What are the actions taken in reducing line loss in distribution system? The key in minimizing the over-all line loss in any distribution system is through current reduction. In computing for the line loss of a distribution feeder we basically use the I^2R formula. The function of current in this formula is in the exponential form. Because of this , a small change in current would be exponentially felt in the power loss of the feeder. Any effort to reduce the line current is also an effort in loss reduction.

  What are the effects of converting the operating voltage of distribution system? In distribution system loss reduction , it has been known that one option of minimizing the losses produced in the distribution system is through voltage conversion. An example would be if a utility has an operating voltage of 13.8kV and they want to reduce their line loss, converting it to 23kV would be an effective move. However, this action can not simply be done without affecting anything especially when considering the economic factors.

DISTRIBUTION LINE LOSS COMPUTATION THROUGH POWER-FLOW ANALYSIS How power-flow analysis is computed in a distribution system? The analysis of a distribution feeder line will typically consist of a study of the feeder under normal steady-state conditions (power-flow analysis) and a study of the feeder under short-circuit conditions (short-circuit analysis). Model of all of the components of a distribution feeder must first be developed before the analysis can be done. These models will be applied for the analysis under steady-state and short-circuit conditions. The power –flow analysis of a distribution feeder is similar to that of an interconnected transmission system. Typically what will be know prior to the analysis will be the three-phase voltages at the substation and the complex power of all of the loads and the load model (constant complex power, constant impedance, constant current, or a combination). Sometimes, the input complex power supplied to the feeder from the substation...

DISTRIBUTION SYSTEM: RADIAL FEEDERS Radial feeder is a distribution feeder line configuration that is known to have one path for power to flow, from the distribution substations (source) to utilization point (end-users). Electric utilities typically have one or more distribution substations each of which consist of one or more distribution feeders. A typical feeder is made up of some if not all of the following components. • Primary main feeder (three phase) • Lateral lines (three-phase, vee-phase and single phase) • Voltage Regulators (usually step-type) • In-line transformers • Capacitor Banks (shunt) • Distribution Transformers • Secondary/Low-voltage lines • Loads (three-phase, two-phase and single phase) Radial feeders can also be described as a distribution line set-up where no other interconnected feeder line is adjacent to it. An outage in its distribution substation means an outage to the whole feeder. Radial feeder can usually b...

DISTRIBUTION SYSTEM: DISTRIBUTION SUBSTATION Power system’s major components can be found in the figure shown below. Among these components includes the distribution system which is said to be the most unglamorous part of the power system network. Presently, utilities use distribution system to continually deliver power to its user with little or no analysis involved. Consequently, this approach tends to make the distribution systems overdesigned. Due to financial considerations, electric utilities today focuses more in maximizing all available resources they can exploit. In electric distribution system, this means maximum capacity should be reached and satisfied. The distribution system scope starts at the distribution substation where it gets its supply from one or more sub transmission lines. However, there are some cases that distribution systems are directly fed from transmission lines. It is in the discretion of the company involved which set up it prefers. Distribution substati...

FACTORS AFFECTING LOSSES IN DISTRIBUTION LINES Power distribution lines nature is to cater loads from every part of a certain area. Also, a typical electrical distribution system is a mesh of distribution lines supplying different kinds of customers from residential to industrial type. Due to the complexity of these networks, a careful analysis is needed to properly evaluate the performance of a certain feeder. Analyzing losses in distribution lines is a very challenging role since it entails careful consideration of all the factors present that affects the losses in a distribution system. Although we have discussed previously that loss in the distribution line follows the I squared R law formula and the key to all of these loss evaluation and reduction is through the line current, ways in reducing the current may not be as easy as it seems. The following terms below are some of the known factors that directly or indirectly influence the losses present in distribution lines. An elect...

DISTRIBUTION LINE LOSS There are two types of power distribution that electric utilities used are known, overhead power distribution and underground power distribution which utilizes power cables and cabinet substations. These two types of distribution methods possess similar and unique characteristics with respect to each other. Overhead lines uses bare wires while underground lines are securely insulated. In evaluating losses on distribution primary lines, a complex and detailed approach is usually necessary since in a power distribution system a great variety of possible line configurations and load conditions exist. We have the familiar distribution set up like a radial, looped and interconnected configuration. It is important for a utility that they are able to evaluate their line losses since through this they can be able to base their decisions regarding loss reduction that can produce significant savings when considered along with other system improvement and plans and new c...

OVERHEAD DISTRIBUTION LINES TYPICAL STRUCTURE CONFIGURATION What are the typical structures used for overhead lines? Transmission lines and Overhead Distribution lines may be similar in terms with their functions but the two differs a lot in terms of their constructions.  Transmission lines are designed to carry high voltage transmission and travels longer distances while overhead distribution lines is made to carry medium voltage transmission and travels distances only depending on the size of its scope or depending to the utilities discretions. In a power distribution system , electrical power leaves the power distribution substation and is distributed to different areas by distribution lines. Distribution lines on the high voltage side of the distribution transformer are called primary distribution lines or primaries. While, secondary are termed to those on the low-voltage side of the distribution transformer are called secondary distribution lines. Typical overhead dis...

DISTRIBUTION LINES: ELECTRICAL DISTRIBUTION SYSTEM A major part of an electrical power system that contributes the most losses in the entire network is usually found in its distribution system. Distribution system or commonly referred to as distribution lines is the part after voltage transformation at the distribution substation is completed. Distribution line’s purpose is to transmit power through conductors to different parts of the utility’s franchise area. These lines typically use medium voltage to circulate power needed by the consumers. Distribution lines is said to be the final stage before satisfying the consumers or end users and when power is delivered to them. Unlike transmission line’s simplicity in operation, distribution lines are far more complicated network of conductors. Distribution network popularly configured in 3-phase, receives electricity from the transmission lines where the voltage is converted first in the substation transformers. As mentioned a while a...