power systems loss

REA BULLETIN 160-2: MECHANICAL DESIGN MANUAL FOR OVERHEAD DISTRIBUTION LINES Overview on REA Bulletin 160-2 for overhead distribution line design guide The engineering input to an overhead line project can be divided into three principal categories; system planning, electrical design of system components, and the mechanical design of the line. This overview for the design manual deals primarily with the last mentioned of these categories. Preparation for an Overhead Distribution Line Project This part involves coordination with system planning especially in the field of route selection and acquisition. This includes securing of rights of way and permits needed for the implementation. Preparing a line project also means preparing of staking aids as well as review of existing design guides or preparation of new ones. The National Electrical Safety Code as a Basis for Distribution Line Design The second part in implementing distribution line projects is insuring that appropriate sta...

SELECTION OF CONDUCTORS FOR OVERHEAD LINE DESIGN What are the guidelines to be considered in selecting conductors for overhead line design? Economically, conductors represent between 20 to 40% of the total cost of a line; consequently their selection is of prime importance. In earlier days of electrical power transmission, copper was mainly used as the material of overhead line conductors, however with the expansion of electricity networks, several factors, such as price, weight, availability and conductivity, have virtually compelled Overhead Line Design Engineers to concentrate on aluminium based conductors, eg. AAC = All Aluminium Conductor ACRS = All Aluminium Conductor Steel Reinforcement AAAC = All Aluminium Alloy Conductor Steel conductors are still widely used as overhead earth wires and also as phase conductors on rural distribution lines, eg. SC/GZ = Galvanised Steel Conductor SC/AC = Aluminium Clad Steel Conductor Phase Conductors The conductors fulfil an electromec...

SELECTION OF INSULATORS FOR OVERHEAD LINE DESIGN What are the guidelines to be considered in selecting insulators for overhead line design? One of the most important and yet one of the most vulnerable links in transmission and distribution is insulators. Porcelain and toughened glass are the materials principally used for supporting conductors on overhead lines, and although these materials are relatively brittle and inelastic, they have proven service experience and are still widely used. The design of synthetic type insulators has improved both electrically and mechanically in recent times and they are being used in urban areas to minimise radio interference and in areas where gunshot or stone throwing is a problem. Insulator damage may occur due to such widely varying causes as lighting (puncture), power arcs, stone throwing, corrosion, gunshot and pollution. The following points must be considered in the selection of the appropriate insulation of an overhead line: • 50Hz perfor...

STEPS IN LAYOUTING DISTRIBUTION LINE IN OVERHEAD LINE DESIGN TUTORIALS How to design overhead line especially in lay-outing distribution line? The following steps are suggested as the approach to be followed in designing a line from scratch. With experience or by reference to the tables of common applications in the Design manual section “Pole Structures” many of these steps will not be required for jobs of a standard nature. 1. Determine conductor size and type based on planning requirements and application. 2. Determine the proposed stringing tension based on the situation eg. Urban, semi urban or rural. Consideration in this decision should be given to the difficulty of staying and frequency of angles required by route restrictions. 3. Determine the Limit state design wind pressure on conductors appropriate to the location (eg 900 or 1200 pa). 4. Determine strain/angle pole locations taking into account the deviation angle limits on pin insulators as per the table in the Desig...

OVERHEAD TRANSMISSION AND DISTRIBUTION LINE DESIGN GUIDELINES OVERVIEW What are the guidelines to be considered in designing overhead electrical lines? In order to minimise the risk of failure of an overhead line it is necessary to ensure that each component of an overhead line has been designed to meet all the electrical and mechanical loads likely to be experienced in service as far as reasonably practical. In order to achieve this, every line and every structure in that line could be individually designed to meet the project requirements. This would be extremely time consuming and is probably only justified for high value transmission lines. Another approach is to utilise a range of standard structures with pre-designed electrical and mechanical capabilities and apply them to a particular project. Selection of Insulators One of the most important and yet one of the most vulnerable links in transmission and distribution is insulators. Porcelain and toughened glass are the materia...

VOLTAGE REGULATORS IN DISTRIBUTION SYSTEM Voltage Regulators used in Power Distribution System? Voltage regulators affect the system efficiency in two ways. First, by maintaining proper voltage on the feeders they serve, regulators reduce losses on lines and distribution transformers supplied by the regulated voltage. Second, losses occur on the regulators themselves. Depending on regulator design, loading, and mode of operation, these losses can be quite high. Regulation at Substations Two major decisions are involved in the choice of regulating equipment to be installed in distribution substations. First, the distributor must decide whether to provide separate regulation for each outgoing distribution feeder or whether some of the feeders will share regulating equipment. For modest-sized substations with only one substation transformer bank and three to five feeders, the decision may come down to the choice between regulating equipment for each feeder and a single, large regulatin...

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...

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...