Урок 4. Unit 4.

1. Найдите в тексте примеры слов, в которых встречаются следующие

звуки и сочетания звуков:

/ Λ / another, …, …, …;

/ ju: / distribution, …, …, …;

/ з: / purpose, …, …, …;

/ i / system, …, …, …;

/ ai / supplies, …, …, …;

/ i: / easily, …, …, …;

/ ð / they, …, …, …;

/ ∫n / distribution, …, …, …;

2. Прочитайте и запомните следующие слова и словосочетания:

a lightning arrestor – грозовой разрядник;

lightning surges – грозовое (атмосферное) перенапряжение;

to extinguish the arc – гасить (погашать) дугу;

a surge crest voltage – максимальное импульсное напряжение; бросок

напряжения; максимальная величина перенапряжения;

to bypass – (зд.) отвести;

a surge discharge – разряд импульсного напряжения;

an outage – простой, перерыв; отключение, перерыв подачи

(электроэнергии); выход из строя;

a failure – отказ (в работе); авария; повреждение; неисправность;

a circuit breaker bushing – высоковольтный ввод выключателя;

to furnish a path – предоставить, обеспечить путь;

to cease to conduct – прекращать (останавливать); зд. не проводит;

rated voltage – номинальное (расчетное) напряжение;

an insurance – гарантия;

severity – интенсивность;

to break down – пробивать; выходить из строя;

to fail – повреждаться; отказывать в действии; выходить из строя; давать

перебои;

ratio – коэффициент трансформации.

3. Прочитайте текст 4. “Transformers”, Part 2. Найдите примеры глаголов-

сказуемых всех грамматических моделей. Укажите предложения, глагол-сказуемое в которых употребляется в сослагательном наклонении. Переведите эти предложения письменно.

TEXT 4. TRANSFORMERS

Part 2

Another type of transformer is the distribution transformer. A distribution transformer is a transformer with a capacity much less than the power transformer. It is normally used for the purpose of providing service to customers. We see distribution transformers on poles or on concrete pads for industrial or commercial application. They provide power for certain services in our systems.

The power transformer is considered a major transformer which is normally of a substantial capacity. A power transformer would be the definition assigned to the transformer which supplies power transforming voltage levels. The utility power transformer would be utilized to transform voltages from high voltage transmission levels to lower levels such as from 230 (two hundred and thirty) kV to 69 (sixty nine) kV or 115 (a hundred and fifteen) kV.

If the purpose of a transformer is to step the voltage down, it could be termed a step-down transformer. A step-down transformer is one that has a secondary voltage lower than the primary voltage.

A step-up transformer is used in conjunction with power generation equipment. After the power is generated, for example at a level of 13.8 (thirteen point eight) or 25 (twenty five) kV, it is stepped up to higher values which more easily permit transmission to distant locations with minimal losses. The power transformers that generation units utilize are of the step-up type.

Tap changers allow change of transformer ratio to give versatility required for utility system operation. Operating at low voltages is not desired. Operation at high voltage can result in over excitation of the transformer, increased noise levels, and greater excitation loss in terms of economics. Simply, it pays to operate at the best ratio for excitation conditions. Load tap changers allow for changing taps under full load conditions.

The type of tap changer which is also common is the “no load tap changer”. In order to operate this no load type, the transformer must be completely de-energized. It may be necessary to shut down, de-energize or change taps several times a year. If conditions remain stable, no changes may be required. As a general rule, voltage levels should be near the tap setting for the best economic considerations. It is possible; however, that other criteria may outweigh the economic considerations in arriving at a tap setting.

Lightning arrestors protect transformers from lightning surges. The purpose of lightning arrestors is similar to that of a safety valve on a boiler. The safety valve relieves a high pressure by permitting the escape of steam. When the pressure is reduced to normal, the valve closes and it is again ready to protect against another abnormal condition. Lightning arrestors operate in a similar manner. When a voltage much higher than normal voltage exists on a line, the arrestor immediately breaks down and furnishes a path to ground. As soon as the voltage returns to normal, the arc is extinguished, the arrestor ceases to conduct and the line returns to normal. Lightning arrestor equipment then must limit the surge crest voltage which may be applied to the apparatus it protects and bypass the surge to ground. The arrestor must be able to withstand its rated voltage and must be capable of extinguishing any power arc which follows the surge discharge.

Application of lightning protection equipment is an insurance against outages and equipment failure. ***The amount and kind of protection needed are influenced by the frequency and severity of storms in the area, the importance of reducing line outages due to lightning and the risk of failure of the equipment used. Generally, the insulation level of the line in the vicinity of the station, within the insulation level of the equipment in the station, should be considered in such a way that the line insulation would break down before the insulation in the station equipment would fail. Line insulators are cheaper and easier to replace than transformers and circuit breakers bushings.

4. Переведите следующие сочетания, обращая внимание на перевод

существительных и причастий в функции определения:

a distribution transformer the definition assigned to the transformer

a power transformer versatility required for the operation

power transmitting voltage levels increased noise levels

the utility power transformer the rated voltage

voltage transmission levels protection needed

a step-down transformer the equipment used

power generation equipment power provided for certain purposes

generation units the utility power transformer utilized to

utility system operation transform voltages

excitation conditions the power generated

load tap changers changes required

a no load type the apparatus applied

a lightning arrestor line insulators replaced

a lightning surge

a safety valve

lightning arrestor equipment

the surge crest voltage

the insulation level

the line insulation

5. Найдите в тексте английские эквиваленты следующих фраз:

1. он обычно используется с целью (в целях);

2. просто выгодно работать;

3. может возникнуть необходимость;

4. тем не менее, возможно;

5. как только напряжение возвращается;

6. в общем;

7. нужно, чтобы … выдерживал;

8. должен быть способен;

9. следует считать (учитывать).

6. Выберите из обеих частей текста “Transformers” информацию о разных

типах трансформаторов и расскажите о их назначении.

7. Расскажите о назначении защитного оборудования.

8. Переведите письменно предложение с ***. Переведите текст на

русский язык.