Electric Power Distribution

МЕТОДИЧЕСКИЕ УКАЗАНИЯ

По организации самостоятельной работы

Магистров заочной формы обучения

По дисциплине «Иностранный язык»

(Английский язык)

 

Направление подготовки

Агроинженерия

Профиль Электротехнологии и электрооборудование в сельском хозяйстве

 

 

Челябинск

2017

Составитель

 

О.И. Халупо - доктор филологических наук, доцент кафедры "Иностранные языки и русский язык как иностранный" (ФГБОУ ВО ЮУрГАУ)

 

Методические указания по организации самостоятельной работы по дисциплине «Иностранный язык» (Английский язык) разработаны в соответствии с требованиями программы данной дисциплины для магистров факультета заочного обучения по направлению 35.04.06 Агроинженерия, профиль - Электротехнологии и электрооборудование в сельском хозяйстве.

Целью данных методических указаний является развитие навыков чтения, перевода текстов по специальности, реферирования материала, усвоение соответствующей лексики для использования знания иностранного языка в процессе поиска, анализа и применения профессиональной информации на иностранном языке.

Text 1

1. Read and translate the text:

Transmission networks

Electric power transmission is the bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation. The interconnected lines which facilitate this movement are known as a transmission network. This is distinct from the local wiring between high-voltage substations and customers, which is typically referred to as electric power distribution. The combined transmission and distribution network is known as the "grid".

Engineers design transmission networks to transport the energy as efficiently as feasible, while at the same time taking into account economic factors, network safety and redundancy. These networks include components such as power lines, cables, circuit breakers, switches and transformers. The transmission network is usually administered on a regional basis by an entity such as a regional transmission organization or transmission system operator.

Transmission efficiency is hugely improved by devices that increase the voltage, and proportionately reduce the current in the conductors, thus keeping the power transmitted nearly equal to the power input. The reduced current flowing through the line reduces the losses in the conductors.

According to Joule's Law, energy losses are directly proportional to the square of the current. Thus, reducing the current by a factor of 2 will lower the energy lost to conductor resistance by a factor of 4.

This change in voltage is usually achieved in AC (alternating current) circuits using a step-up transformer. HVDC (high voltage, direct current) systems require relatively costly conversion equipment which may be economically justified for particular projects, but are less common currently.

A transmission grid is a network of power stations, transmission circuits, and substations. Energy is usually transmitted within a grid with three-phase AC. Single phase AC is used only for distribution to end users since it is not usable for large polyphase induction motors. In the 19th century, two-phase transmission was used but required either three wires with unequal currents or four wires.

2. Find Russian equivalents of the following English words and word combinations and learn them by heart:

transmission network; to transport the energy; power lines; cable; circuit breaker; switch; transformer; transmission efficiency; conductor; equal; the power input; energy losses; current; resistance; voltage; circuit; step-up transformer; equipment; substation; transmission grid; AC; distribution; induction motor; wire.

3. Answer the following questions:

1. What are the transmission networks designed for?

2. What are the components of the transmission networks?

3. Who administrates the transmission networks?

4. What does the transmission efficiency depend on?

5.  How is the change in voltage achieved?

6. What is a transmission grid?

7. Why is single phase AC used only for distribution to end users?

 

4. Discuss these issues in the group (or write an abstract):

1. Disadvantages of transmission networks in our country.

2. Transmission energy efficiency is the main task for engineers.

 

Text 2

1. Read and translate the text:

Electric Power Distribution

Electric power distribution is the final stage in the delivery of electric power; it carries electricity from the transmission system to individual consumers. Distribution substations connect to the transmission system and lower the transmission voltage to medium voltage ranging between 2 kV and 35 kV with the use of transformers. Primary distribution lines carry this medium voltage power to distribution transformers located near the customer's premises. Distribution transformers again lower the voltage to the utilization voltage used by lighting, industrial equipment or household appliances.

Most electrical power is produced by generators capable of generating many thousands of watts. The generators are driven by turbines which receive power from either steam pressure or water pressure created by the heads of water behind large dams. The generators are owned and operated by various power suppliers including public utilities, cooperatives and municipalities.

A schematic diagram of the power distribution from the generator to the consumer is illustrated in the figure below.

                                Step-Up Transformer        Substation Step-Down Transformer  

                            

 

Electric power distribution from generating plant to low voltage (normally 115/230 v) distribution system

 

 After generation at 2.3 - 13.8 kV the electricity travels to a transformer where the voltage is stepped up to several thousand volts; in some cases it approaches one million volts. This high voltage electricity may travel for many kilometers. With the higher voltage, a lower current is developed, causing lower I2R losses (where I (amperes) is the current flowing in the conductor and R (ohms) is the resistance of the conductor). Thus, the losses due to resistance heating are reduced greatly in night voltage transmission lines. Along the way there may be step-down transformers that lead to secondary transmission lines. As the lines near residential areas, communities, or industries there generally is a substation located in which there are further step-down transformers. From these substations are primary mains that may carry only a few thousand volts (e.g. 2,300). Then from the primary main the electricity may be taken off at distribution transformers to secondary mains that carry 115/230 v for most resi­dences, farm customers, and small business and industries. The ser­vice wires at 115/230 v then go to a meter and hence into the resi­dential or farmstead electrical distribution system. Some higher voltage systems, such as 220/440 v areused for small business or pro­cessing and manufacturing plants.

2. Find Russian equivalents to the following English words and word combinations and learn them by heart:

electric power distribution; to carry; consumer; medium voltage; primary; industrial equipment; household appliances; to generate; to drive; to receive; steam pressure; power supplier; to step up; to develop; secondary transmission lines; residential area; substation; step-down transformer; industry; manufacturing plant.

3. Answer the following questions:

1. Is the electric power distribution the first stage in the delivery of electric power?

2. Where is electricity carried from the transmission system?

3. What is the purpose of distribution substations?

4. What are the generators driven by?

5. Who owns and operates the generators?

6. When is the voltage stepped up?

7. What voltage systems areused for small business or pro­cessing and manufacturing plants?

 

4. Discuss these issues in the group (or write an abstract):

1. The growing demand for electricity.

2.Electric power distribution in rural areas.

Text 3

1. Read and translate the text: