The use of underground power distribution has grown significantly over the years with the rapid increase in demand for electric energy and the trend for large infrastructures and the vast expansion of highly-populated metropolitan areas. Traditional methods of cable ampacity calculations are all based on the analysis which approximates the cable circuit configuration and assumes uniform soil conditions around the cable.
Such approximations and assumptions lead to inaccuracies in the calculations and often force cable engineers to use unnecessarily large safety factors and overly conservative designs, this paper presents an improved technique using the finite-element method to calculate the steady-state temperatures at various points of the cable ampacity corresponding to a specified maximum conductor temperature. An application to a cable system in the QATAR GENERAL ELECTRICITY & WATER CORPORATION (Q.G.E.W.C) network is also presented.
With the rapid increase in demand for electric energy and the trend for large infrastructures and vast expansion of highly-populated metropolitan areas, the use of underground power distribution has grown significantly over the years both worldwide and the STATE OF QATAR in the power grid of the QATAR GENERAL ELECTRICITY & WATER CORPORATION (Q.G.E.W.C.) for example, there is an extensive underground cable network covering thousands of kilometers and spanning various voltage levels, including the 11kv distribution and the 400kv transmission system, QATAR GENERAL ELECTRICITY & WATER CORPORATION (Q.G.E.W.C.)
The first shelter on earth constructed by a relatively close ancestor to humans is believed to be built 500,000 years by an early ancestor of humans, Homo erectus. As a Civil Engineering structures such as a house, worship center, factories, etc. that has a foundation, wall roof, etc. that protect human being and their properties from the direct harsh effect of weather like rain, wind, sun, etc.
Any building requires a certain amount of internal infrastructure to function, which includes such elements as heating/cooling, power, and telecommunications, water, and wastewater, etc. Especially in commercial buildings (such as offices or factories), these can be extremely intricate systems taking up large amounts of space (sometimes located in separate areas or double floors/false ceilings) and constitute a big part of the regular maintenance required.
Street Lighting is an excellent way of increasing road and general safety at night and improves the quality of life for residents by helping to deter and reduce the fear of crime. Urban development programs are increasingly focused on rehumanizing the urban environment, and we believe street lighting has a vital role to play in this regard, creating an appealing, inclusive ambiance. NEMCCO’s immense target and achievement to provide an excellent service in design, supply, installation with testing & commissioning of street /highway road lighting system including civil & builder works to hand over the job to the customer or clientele satisfaction.
The dynamic changes in the economy, energy supplies, and ecology on a world scale require an adequate modernization of street lighting. However, this would be possible only with a quite new functional conception which in fact means adaptability of street lighting. Simultaneous ensuring of the conditions of the same traffic and decreasing the energy consumption and operational costs could be realized in conformity with the constantly changing parameters of the environment. In conformity with the 24 hours change of daylight, the highly changeable traffic, the variable meteorological conditions and some extreme situations on the roads, the intensity of street lighting should change in a dynamic manner new technical devices and methods that are offered by technical progress will be necessary obviously for the realization of adaptive lighting.
Overhead transmission of electric power has been a long the years and will still continue as one of the most important elements of today's electric power system. Power transmission from generating stations to industrial sites and to substations is the fundamental object of the transmission system. This function is accomplished by overhead transmission lines that connect the power plants into the transmission network, interconnect various areas of transmission networks, interconnect one electric utility with another, or deliver the electric power from various areas within the transmission network to the distribution substation, from which the distribution system supply residential and commercial consumers.
The primary purpose of an electricity distribution system is to meet the customer's demand for energy depending on the geographical location, the distribution network can be in the form of overhead lines or underground cables. Cables are commonly used in urban areas and overhead lines are adopted for rural areas. Different networks configurations are possible in order to meet the required supply reliability.
Planning of the distribution network is essential to enable the required demand can be met based on various forecast loading figures and supply security/reliability. There are three categories of planning, namely long-term planning, network planning, and construction planning. Long-term planning is to determine the most optimum network arrangements and the associated investment with consideration of future developments. Stage-by-stage development must be in line with the forecasted load growth so that electricity demands can be timely met. The construction planning or design or design is the actual design and engineering work when the required circuits and substations have been planned and adopted.
Distribution network refers to those 33kV or 11kV networks supplying electricity to customers through overhead line (OHL). From primary substations to various customer substations. OHL network is more likely to be disturbed by external factors, for example, lighting, animals, or plants. Some of the disturbances are temporary so the circuit breakers at the source end substation are equipped with the auto-reclose capability to cater for transient fault. In a long OHL situation, auto-recloser can be adopted. The modern approach is the use of a pole-mounted switch with remote control facilities. The installation of a lightning arrester can improve the transient response capability of the OHL. Regular maintenance like a vegetation management program can reduce unnecessary tripping, particularly during a possible line overhead situation. Such measures could minimize the impacts resulting from these external disturbances.
Substation switchgear requires regular cleaning in accordance with its design, type of insulation, the degree of pollution of the atmosphere or ambient air, etc. The frequency of cleaning depends upon the type of layout of the apparatus and insulators. However, cleaning must be done during each preventive maintenance.
In the daily operation of the substation, it is the duty of the attendant to inspect the equipment externally and remedy any abnormality that does not require disconnection of the apparatus. During this inspection, a watch is required to be kept for deposits of dust and dirt on the insulators heating of a contact, joint of some part, low oil level, and oil leakage, etc.
A check should also be made that the locks and doors of the switch house are in good condition, no leaks have developed in the roof, the ventilating and heating systems are operating normally, the prescribed safety aids are in place and in good order, the earthing connection remains unbroken, the packing of the cables entering or leaving a cable trench or tunnel within the premises are intact, the ventilating louvers are not damaged, the access roads leading to the oil-filled apparatus are unobstructed and will allow the approach of the fire engines in the event of an oil fire during an emergency.
Distribution Maintenance Program requires the distribution Utilities (DU) to prepare distribution maintenance program based on forecasted demand, user's provisional maintenance program, and requests for a maintenance schedule,
(1) 3 – year maintenance program.
(2) Annual Maintenance program.
(3) Monthly maintenance program.
(1) Electrical Equipment – Designed for certain economic service life.
(2) Equipment Life – Dependent on the operating environment, maintenance program, quality of the original manufacture, and installation.
(3) Beyond Service Life Period – They are not expected to render their services according to their expectations with the desired efficiency.
General Causes of Equipment Failure Much Earlier Than Expected Economic Life span?
(1) Poor quality of raw material.
(2) Workmanship and manufacturing techniques.
(3) Frequent electrical, mechanical, and thermal stresses during the operation.
Each year thousands of properties are damaged or destroyed by lightning. Lightning accounts for more than one billion dollars annually in structural damage to buildings. What is not reported is the loss of business, Insurers now require higher levels of safety for commercial buildings, schools, hospitals, institutions, historic landmarks, sports arenas, and other public venues, including the installation of lightning protection systems and Minimizes the risk of significant property damage caused by lightning strikes also helps protect your investment from liability, downtime, and loss of business in the event of lightning damage. Demonstrates your commitment to safety to insurers, local inspectors, and commercial tenants, After the system has been installed, the UL Listed installer completes and submits the certification application. Contact your installer if the building changes structurally or if modifications have been made to the system during the five-year period that the certificate is in effect. Your installer can repair or modify the system
The watering-place has always been the focal point of life on earth. First animals and then humankind clustered around their source of freshwater. Both animals and humans can exist for weeks without food, but without water, life ceases within days. Wells was one of the humans' earliest construction activities.
The earliest wells are known from the Neolithic era. Neolithic refers to the time period roughly 7,000-10,000 BC well construction seems to date from the time of the adoption of a series of behaviors common to the people of a given region. These behaviors include the widespread use of farming, the keeping of domestic animals.
Ensuring that water wells are constructed in a manner that does not compromise water quality and the environment is a critical component to proving safe potable water to the citizens of New Brunswick. For this reason, when a new well is developed by a water well contractor, the property owner is charged a fee prescribed in the potable water regulation (93-203) – clean water act to provide portability testing.
Water well contractors and well drillers are responsible for renewing their permits each year and for constructing water wells according to regulatory requirements in terms of the materials used, construction methods, and location of the well on a given property and in relation to potential sources of contamination. The good contractor is also responsible for attaching an identifying tag to the good casing and the good owner is provided with a voucher to have a water quality analysis done at the department are provided with a copy of the good log it is important for a good owner to redeem their voucher in order to be aware of the quality and portability of their drinking water.
Directional drilling address the design of major pipeline or duct segments to be installed by horizontal directional drilling (HDD), Generally speaking, major pipeline segments are greater than 500ft in length and greater than 4in. in diameter. They are installed by medium to large HDD rigs ( Midi to Maxi-HDD rigs).
Horizontal directional drilling is a trenchless excavation method accomplished in three phases. The first phase consists of drilling a small-diameter pilot hole along a designed directional path. The second phase consists of enlarging the pilot hole to diameter the pipe into the enlarged hole. Horizontal directional drilling is accomplished using a specialized horizontal drilling rig with ancillary tools and equipment.
NEMCCO hold a Class ‘A’ license issued by Qatar General Electricity & Water Corporation (KAHRAMAA), and have also been pre-qualified by the same department for the following: