Passage 1 Feature of power generation
1. They electric power can stored.)
2. The power system is made up of 4 parts.
3. The unification of power system equipment is formed by 4 equipments.
4. A power system is an undivided integer.
5. The power network can operate normally without the integration of other 3 equipments.
6. A link line is called a transmission line.
7. A link line is formed by 3 power networks.
8. An electric power network is simply called a power network
9. The main network frame is formed by a weak EHV system.
10. The networks are not closely linked with each other
Passage 2 Types of circuit breaker
1. Contactors, are-extinguishing elements, insulation material and operating mechanism form the high
voltage circuit breaker.
2. The insulation structure is made up of 3 parts
3. The are-extinguishing medium can be divided into only 3 parts
4. An oil circuit breaker means a circuit breaker with oil as are-extinguishing and insulation
medium
5. A vacuum circuit breaker is not a circuit breaker with close and open contactors in high
vacuum
6. A pure SF6 gas is not a food are-extinguishing medium.
7. The insulation strength of SF6 gas is higher than air and vacuum.)
8. An oil minimum circuit breaker is very safe in use
9. An oil minimum circuit breaker has bad heat dissipation capability
10. An oil minimum circuit breaker is one of the mostly used circuit breakers in the power grid Passage 3 Optical fiber communication
1. A kind of information communication is optical fiber communication
2. The composite optical fiber ground wire is seldom used in power system
3. One of the transmission tasks of the optical fiber main network is to transmit administration telephones
from power system)
4. Optical fiber communication has been the important communication method in power communication
system
5. Large capacity of communication is not one of the advantages of optical fiber communication
6. The communication capacity of optical fiber is indirectly proportion to the carrier frequency
7. The carrier frequency of power line is more than 300kHz
8. The carrier frequency of microwave is between 3000Mha and 500MHz.
9. The main problem of the fiber-optic channel is the high price of fiber-optic equipmen
10. The cables made by optical fiber are not expensive
Passage 4 Power plant
1. Base on energy conversion, power plants are divided into more than 7 categories
2. A power plant tries to transform energy source into electric power
3. The power plant generating electricity and supplying steam is called a co-generation plant.
4. A power net plan for short and medium term is one of factors in selecting a site )
5. Two important factors for a new plant plan are fuel supply and ash disposal
6. Environmental protection is less considered in building a new power plan
7. Water sources and transportation conditions are not needed to consider in selecting a new site
8. The total capacity in a newly scheduled plant arranges from 1200MW to 3600MW
9. The number of units exceeds more than six
10. The ranks of capacity should be limited within two
Passage 5Selection of metal material for the boiler in units of 1000MW grade
1. The 1000MW grade high-efficiency supercritical unit is designed and made in China
2. The temperature of main steam and reheated steam reach basically between 570 to 650℃
3. The tube wall temperature of superheater and reheater can reach more than 600 to 650 ℃
4. The tube wall temperature steam oxidation performance at tube inner surface is highly demanded
5. The anti-high temperature flue gas corrosion performance at tube outside surface is not highly
demanded6. The temperature limit of T91 for use is about 593℃
7. The temperature limit of T92 for use is less than 620℃
8. The temperature of austenite stainless steel for normal use is about 650℃
9. The temperature limit of austenite stainless steel is less than 700℃
10. Only heat-resisting steel can be adopted for use
Passage 6 The role of the condenser
1. A condenser is a heat exchanger removing the vaporization heat from the exhaust steam and condensing
the exhaust steam into water
2. It is suggested that the water should not be cooled below the saturation temperature3. The saturation temperature would not remove excess energy from the system and reduce the overall
efficiency
4. It is unnecessary to reduce the steam to water so that it can be pumped back through the system
5. The condenser does not control back-pressure at the turbine exhaust6. The important factor controlling the turbine backpressure is the temperature of the cooling water
passing through the condenser tubes7. The temperature of cooling water will increase its temperature between 15oF and 20oF as it passes
through the condenser.8. The terminal difference means the temperature difference between the cooling water and the turbine
exhaust steam
9. The temperature increase of the cooling water and the terminal difference depend on 3 factors.10. The exhaust steam temperature does not rely on the temperature of the cooling water which enters the
condenserPassage 7 Hydraulic structure
1. The type of dam for hydraulic power plant depends on many factors2. The main purpose of the dam safety monitoring is to discover the normality of dam in time
3. The equipment installed inside the dam is to discover the normality of dam in time.
4. Horizontal displacement is more important than vertical displacement
5. Temperature stress and strain are the two main monitoring items of dam
6. The monitoring method is the suitable points on the dam and its foundation.
7. Some monitoring devices are movable for periodical supervision.)
8. The monitoring result result shall be analyzed and studied by computers.
Passage 8 Heat treatment
1. The post-weld heat treatments have two main purposes
2. One of the purposes is to diminish the residual stress in the welded joints.
3. The other purpose is to improve the organization of the welded joints
4. The welding crack can be classified into 5 categories
5. To change the internal structure of the work piece is one of purposes for heat treatment
6. There are 5 kinds of steel heat treatment
7. The processes of heat treatment include 4 procedures.
8. The electric resistance furnace is not widely used9. Heat treatment furnaces are not composed of electric resistance furnace, combustion furnace and surface