Switching substation

Switchyard at Grand Coulee Dam, USA, 2006

A switching substation is a substation without transformers and operating only at a single voltage level. Switching substations are sometimes used as collector and distribution stations. Sometimes they are used for switching the current to back-up lines or for parallelizing circuits in case of failure.

A switching substation may also be known as a switchyard, and these are commonly located directly adjacent to or nearby a power station.

Вправа 3. Дайте відповіді на питання.

1. What is a substation?

2. What do substations transform?

3. How may be substations owned and operated?

4. What do substations include?

5. What equipment do substations have?

6. What are the elements of substation?

7. What are the types of substations?

8. What do you know about transmission (distribution, switching) substations?

Вправа 4. Виберіть правильні твердження по тексту.

1. A substation is a part of an electrical instrument.

2. Substations transform voltage from high to low, or the reverse, or perform any of several other important functions.

3. A substation may include transformers to change voltage levels between low transmission voltages and lower distribution voltages, or at the interconnection of two different transmission voltages.

4. The first substations were connected not to only one power station, where the generators were housed, and were subsidiaries of that power station.

5. In a large substation, circuit breakers are used to interrupt any short circuits or overload currents that may occur on the network.

6. Other devices such as capacitors and voltage regulators may also be located at a substation.

7. The simplest case is where all transmission lines have the same voltage.

8. A distribution substation transfers power from the transmission system to the distribution system of an area.

9. Input voltage may be, for example, 200 kV, or whatever is common in the area.

10. A switching substation is a substation without transformers and operating only at a single voltage level.

Вправа 5. Розшифруйте абревіатури.

a.c., a.f., bev., cgs., c.p.s., db, d.c., e.m.f., e.v., i.f., r.f., sq.

Вправа 6. Перекладіть речення.

1. Selection of the location of a substation must consider many factors.

2. Sufficient land area is required for installation of equipment with necessary clearances for electrical safety, and for access to maintain large apparatus such as transformers.

3. Where land is costly, such as in urban areas, gas insulated switchgear may save money overall.

4. The site must have room for expansion due to load growth or planned transmission additions.

5. Environmental effects of the substation must be considered, such as drainage, noise and road traffic effects.

6. A grounding (earthing) system must be designed.

7. The total ground potential rise, and the gradients in potential during a fault (called "touch" and "step" potentials), must be calculated to protect passers-by during a short-circuit in the transmission system.

8. The substation site must be reasonably central to the distribution area to be served.

9. In a common design, incoming lines have a disconnect switch and a circuit breaker.

10. In some cases, the lines will not have both, with either a switch or a circuit breaker being all that is considered necessary.

Виконання вправ на закріплення граматичної теми

Вправа 7. Складіть анотацію до тексту.