I. Right and wrong issues

1. Choose a smaller fuse to protect the motor from overload. wrong

2. A motor is an electrical device that converts electrical energy into mechanical energy. correct

3. Three types of tools rely on safe ultra-low voltage for power supply, and no voltage higher than safe ultra-low voltage will be generated inside the tools. correct

4. Class I tools not only rely on basic insulation to prevent electric shock, but also include additional safety precautions. correct

5. When the same stretcher is set, the conductor phase sequence is: L 1, n, L2, L3 face the load from left; correct

6. In order to ensure the mechanical strength of conductor 3 ~ 10 kV line, the section of aluminum conductor in residential area should not be less than 16mm2. wrong

7. The selection of conductor should meet the requirements of mechanical strength, safe current carrying capacity and allowable voltage loss of conductor. correct

8. When the circuit breaker fails, the disconnector (circuit breaker) can be opened and closed with load. wrong

9. If there are serious personal safety hazards, please fill in the switching operation ticket before the power failure. wrong

10. Pay special attention to switch operation and fuse replacement when lightning strikes. wrong

165438+ right

12. The cold standby state refers to the state where the switch and circuit breaker are in the off position and the equipment stops running. In order to make the equipment run, the circuit breaker must be closed first, and then the working state of the switch must be closed. correct

13. The hot standby state means that the circuit breaker is in the closing position, but the circuit breaker (switch) is in the off position, the power supply is interrupted and the equipment is shut down. correct

14. When it is necessary to patrol outdoor high-voltage equipment in thunderstorm weather, you should wear insulating boots and keep a sufficient distance from the charged body. correct

15. During accident handling or brake switching operation, the shift can be completed on time after work. wrong

16. Three groups of single-phase grounding wires can be used instead of a group of three-phase short-circuit grounding wires. wrong

17. The operator can remove and hang the grounding wire without wearing insulating gloves. wrong

18. Check the electricity before hanging the ground wire to prevent the ground wire from being charged. After confirming that the equipment has no electricity, immediately ground the power-off equipment and conduct three-phase short circuit. correct

19. For outdoor electricity inspection in rainy days, ordinary (waterproof) electroscope or insulating pull rod can be used. Wrong.

20. It is not necessary to turn off the high-voltage equipment when working on the secondary wiring circuit. You need to fill in the first working ticket. wrong

2 1. Generally, the metal shell of electrical equipment installed on wooden structures or wooden towers does not need to be grounded. correct

22. When the electrical equipment grounding fault occurs, the closer to the grounding point, the higher the step voltage. correct

23. In TN-S system, the metal shell of all electrical equipment is connected to the protection. correct

24. In the same low-voltage power supply system, it is allowed to adopt protective grounding and protective zero connection at the same time. wrong

25. Indirect contact with electric shock is the phenomenon that the human body comes into contact with the metal shell or metal frame of uncharged equipment under normal circumstances. Step voltage electric shock belongs to indirect contact electric shock. correct

26. Class III hand-held power tools and class III mobile household appliances must be equipped with leakage protectors. wrong

27. When the electrical equipment adopts safe voltage of more than 24V, protective measures must be taken to prevent direct contact with charged bodies. correct

28. The voltage that the human body can continuously contact without causing direct death or disability is safe voltage. correct

29. Insulating rods and insulating clips are basic safety appliances for insulation. correct

30. When the fence is used for outdoor power distribution equipment, its height should not be less than 1.5m, and the fence spacing and distance from the ground should not be less than 0.2m Correct.

3 1. The insulation resistance to ground of low-voltage electrical equipment and low-voltage lines in operation should not be lower than 1kω/v .. Correct.

32. The minimum safe distance between hoisting machinery and heavy objects and 10KV line should be greater than 2m. correct

33. The minimum safe distance between the patrol human body on duty and the uninterruptible power supply equipment below 10KV is 0.3m.. wrong

34. Maintaining good insulation of distribution lines and electrical equipment is the most basic element to ensure personal safety and normal operation of electrical equipment. correct

35. The basic principle of safe electricity use is "safety first, prevention first". correct

36. If the person who gets an electric shock stops beating and breathing, and if the electrician present can't wake the person who gets an electric shock after five hours of rescue, you can assume that the person who gets an electric shock is dead. wrong

37. Extracorporeal cardiac compressions should be performed about 60 times per minute. wrong

38. "Electric Safety Work Regulations" lists emergency rescue methods as one of the necessary working conditions for electric workers. correct

39. Step voltage electric shock also belongs to indirect contact electric shock belongs to direct contact electric shock. wrong

40. Indirect contact electric shock refers to the phenomenon that the human body directly contacts a charged body or the human body is too close to a charged body and gets an electric shock. wrong

4 1. Getting rid of current is the maximum current that people can stand and get rid of independently. correct

42. Electric shock is the physiological reaction and pathological change of internal organs caused by current passing through human body. correct

43. Electric injury is a trauma caused by electric current passing through the human body. correct

44. The so-called electric shock refers to the physiological and pathological damage caused to the human body when the current passes through the human body. correct

45. In the neutral grounding system, the electrical equipment with protective grounding will still get an electric shock accident if the human body touches the equipment shell when the phase line contacts the shell. correct

46. For lines with multiple motor loads, the rated fusing current of the fuse should be greater than or equal to 1.5 ~ 2.5 times of the sum of the rated currents of each motor. wrong

47. When using RL spiral fuse, the central contact of its base is connected to the load, and the spiral part is connected to the power supply. wrong

48. High-voltage fuses have clear time-limit characteristics. wrong

49. In order to avoid the influence of short-circuit current, the current transformer must be blown. wrong

50. There is no special requirement for grounding (zero connection) in explosive dangerous places. wrong

5 1. Electrical safety inspection is a necessary measure to nip in the bud. wrong

52. Hand-held electric tools should be managed by special personnel, and their safety and reliability should be regularly checked. Class II and class III should be selected as far as possible. correct

53. In order to ensure safety, hand-held power tools should try to choose Class I ... wrong.

54. When measuring resistance with multimeter, power must be cut off, and when measuring resistance with shaking table, it is unnecessary to cut off power. wrong

55. When electrical equipment is on fire, immediately cut off the power supply of related equipment, and then use foam extinguisher to put out the fire. wrong

56. Enter the aerial work site, should wear a helmet. Workers working at height must use safety belts. correct

57. Power cable power outage work should fill in the first working ticket, no power outage work should fill in the second working ticket. correct

58. Measuring the insulation of high-voltage equipment with a shaking table can be done by one person. wrong

59. The personnel on duty on the high-voltage line using clamp ammeter measurement work, must be carried out by two people. When measuring, non-working personnel should fill in a second working ticket. correct

60. Using portable instruments to work on high-voltage circuits requires high-voltage equipment to cut off power or take safety measures. You don't need to fill in a working ticket, you can do it alone. wrong

6 1. Fences or fences should be installed at the test site, and "Stop, high voltage danger!" Sign it and send someone to guard it. When the two ends of the tested equipment are not in the same place, the other end should also be guarded. correct

62. Fill in the high voltage test working ticket. wrong

63. high voltage test can do it alone. wrong

64. Live working must be supervised by designated personnel. The guardian should be a person with practical experience in live working. The guardian shall not operate directly. The monitoring range shall not exceed one working point. correct

65. The partial power outage refers to the partial power outage of high-voltage equipment or indoor power outage, but the doors leading to the adjacent high-voltage rooms are not all locked. correct

66. In case of personal electric shock accident, in order to rescue those who get an electric shock, the power supply of related equipment can be disconnected without authorization, but it must be reported to the superior immediately afterwards. correct

67. The braking operation must be carried out by two people, one of whom is familiar with the equipment as a guardian. correct

68. Patrol distribution equipment, in and out of the high pressure chamber, must lock the door. correct

69. The personnel on duty must be familiar with electrical equipment, and the personnel on duty alone or the person in charge on duty should also have practical work experience. correct

70. After the operation of the leakage protector, the fault should be eliminated according to the action reason before the closing operation can be carried out. It is forbidden to send electricity forcibly with faults. correct

7 1. should be used in safe voltage, and leakage protector should not be used instead. correct

72. The rated leakage current is not more than 30mA leakage protector, when other protection measures fail, can be used as a direct contact type of supplementary protection, but not as the only direct contact protection. correct

73. The electrical equipment and temporary lines on the construction site must be equipped with leakage protectors. correct

74. Hand-held power tools (except Class III), mobile household appliances (except Class III), other mobile mechanical and electrical equipment and electrical equipment with high risk of electric shock must be equipped with leakage protectors. correct

75. safe voltage should be used instead of leakage protector. When it is really difficult to use safe voltage, it must be approved by the safety management department of the enterprise before using the leakage protector as supplementary protection. correct

76. Choose leakage protector, should meet the requirements of using power supply voltage, frequency, working current and short circuit breaking ability. correct

77. The running leakage protector should be checked regularly, at least once a month, and make inspection records. The inspection contents include appearance inspection, test device inspection, wiring inspection, signal indication and button position inspection. correct

78. The leakage protector fails, and qualified leakage protector must be replaced. correct

79. The protection scope of the leakage protector should be an independent circuit and cannot be electrically connected with other lines. When the capacity of one leakage protector is insufficient, two leakage protectors cannot be used in parallel, and the leakage protector with the required capacity should be selected. correct

80. When installing the leakage protector, check the product certificate, certification mark and test device, and stop the installation if abnormal conditions are found. correct

8 1. As the earth leakage protector is installed, it is unnecessary to use safe voltage when working in a metal container. wrong

82. When working live on the low-voltage power supply line with leakage protector, it is unnecessary to take safety measures such as insulating gloves and shoes. wrong

83. When the charged equipment is on fire, dry fire extinguishers and CO2 fire extinguishers should be used to put out the fire, and foam extinguisher should not be used. correct

84. Found someone get an electric shock on the pole or high place, conditional should strive for timely rescue on the pole or high place. correct

85. Cardiopulmonary resuscitation should be carried out on the spot, but the wounded can be moved at will for convenience. wrong

86. Skilled waiter, simple operation can be completed by experience and memory, without operation ticket. wrong

87. When the line is out of power, it must be operated in the order of circuit breaker, bus side disconnector and load side disconnector, and vice versa when sending. wrong

88. When using the clamp table, the two surfaces of the jaw should be in good contact without impurities. correct

89. When measuring insulation with a megger, the E end is connected to the wire and the L end is grounded. wrong

90. The metal shell grounding of electrical equipment belongs to working grounding. wrong

9 1. When patrolling outdoor high-voltage equipment in thunderstorm days, wear insulating boots and stay away from lightning arresters and lightning rods. correct

92. Workers are prohibited from moving or removing fences, grounding wires and signs at work. correct

93. Dispatching at all levels is the superior-subordinate relationship in power system operation command. The duty dispatcher, the shift supervisor of power plant and the shift supervisor of substation of lower dispatching institutions are under the command of the duty dispatcher of higher dispatching institutions. correct

94. The disconnector can close the trouble-free voltage transformer and lightning arrester. correct

95. The meaning of "ground" in electricity refers not to the earth, but to the place where the potential is zero. correct

96. Transformer cooling methods include oil-immersed self-cooling, oil-immersed air-cooling, strong oil-air cooling and strong oil-water cooling. correct

97. When high-voltage equipment is grounded, the safe distance between human body and grounding point is: indoor should be greater than 4 m, outdoor should be greater than 8 m ... Correct.

98. Fill in the operation ticket, including the operation sequence, sender, operator, guardian and operation time of the operation task. correct

99. If you have any questions about switching operation, you can change the operation ticket before operation. wrong

100. Switching operation of substation (station) must be carried out by two people, among whom the person familiar with the equipment is the guardian. correct

10 1. The executed operation ticket is marked as "Executed". Invalid operations should be marked with the word "invalid". These two kinds of operation tickets shall be kept for at least three months. correct

102. Each operation ticket can only fill in one operation task, and each operation should be marked with "√". correct

103. Power grid is a part of power system, which is a unified network composed of various substations and transmission and distribution lines with different voltage levels. correct

104. The power system is a part of the power system, which consists of generators and distribution devices of power plants, step-up and step-down substations, transmission and distribution lines and electrical equipment of users. correct

105. Step voltage means that if there is a potential difference between two points with a horizontal distance of 0.8m on the ground, human feet will bear voltage when they touch these two points. Right?

106. The barrier is the screen protection of equipment installed to prevent workers from touching the live parts of the equipment by mistake, and it is divided into temporary barrier and permanent barrier. correct

107. When there is unexpected voltage on power-off equipment and lines, grounding wire is an important tool to ensure the safety of workers. According to the regulations issued by the Ministry, the grounding wire must be made of bare copper core wire of more than 25mm 2. correct

108. The high-voltage test pen is used to check whether the high-voltage network distribution equipment, overhead lines and cables are charged. correct

109. Transformer is a kind of static electrical equipment, which is used to convert a certain value of AC voltage into another or several different values of the same frequency AC voltage. correct

1 10. Current transformer, also known as instrument converter, is an instrument that changes a large current into a small current. correct

1 1 1. In RLC series circuits, the effective value of the total voltage is always greater than that of each component. wrong

1 12. When the transmission line under the jurisdiction of the user stops sending power, it is up to the user applicant to decide. correct

1 13. When people get an electric shock, they should immediately carry out cardiopulmonary resuscitation. wrong

1 14. Changing the power frequency of asynchronous motor will change the speed of motor. correct

1 15. After the power failure of electrical equipment, it is forbidden to touch the equipment or enter the fence of the equipment before disconnecting the power switch and taking safety measures, so as to avoid personal electric shock accidents. correct

1 16. If the transformer capacity is below 500kVA and the power supply is introduced from the secondary substation in the factory, only patrol inspection can be arranged without designated personnel on duty. correct

165438+ wrong

1 18. When the substation is out of power, it is not necessary to fill in the operation ticket after the circuit is cut off. wrong

1 19. During the operation of the substation, it is not necessary to fill in the operation ticket for connecting or disassembling the grounding wire, checking the electricity and assembling and disassembling the fuse of the voltage transformer circuit. wrong

120. The operation of electrical equipment must be carried out by two people, with the lower working level as the guardian and the higher working level as the operator. wrong

12 1. Single operation, accident handling operation, disconnecting grounding knife and removing only one set of grounding wires are not required to fill in the operation ticket, but should be recorded in the operation record book. correct

122. Check the insulation resistance between stator and rotor windings of low-voltage motor and between windings and ground. When measured with 500V insulation resistance, its value should not be less than 0 .5M, otherwise it should be dried. correct

123. When the wound rotor asynchronous motor is started with rotor series resistance, the greater the series resistance, the greater the starting torque. wrong

124. the starting mode of wound rotor asynchronous motor often adopts Y-δ decompression starting. wrong

125. The insulation level of the motor indicates the level of the temperature limit that the insulation materials and wires of the motor windings can withstand. For class E insulation, the maximum allowable temperature is 120℃. correct

126. When the asynchronous motor starts with Y-δ step-down, the stator winding is connected with δ first, and then with Y connection. wrong

127. The rated voltage of the motor refers to the voltage of each phase input to the stator winding, not the voltage between lines. wrong

128. The phase (fire) line of the screw lamp holder should be connected to the tongue piece in the center of the lamp holder, and the zero line should be connected to the screw. correct

129. It is the same whether the power cord is connected to a socket or a plug. wrong

130. The protective grounding terminal (facing the top of the socket) and the neutral terminal (facing the leftmost hole of the socket) of the single-phase three-hole power socket can be connected by wires, and * * * uses one wire. wrong

13 1. Generally, the electrical safety inspection is conducted every quarter 1 time. correct

132. When the transformer is out of power, stop the load side first, then the power side, and vice versa. correct

133. The motor shell must have reliable protective grounding or zero connection. correct

134. If a single-phase transformer with a rated voltage of 380 V /220 V is used as a step-up transformer, a power supply of 380 V can be connected to the secondary side, and a voltage of about 656 V can be output at the primary side. wrong

135. safe voltage lighting transformer adopts double-ring transformer or autotransformer. wrong

136. The power phase (fire) line can be directly connected to the lamp, and the switch can control the ground wire. wrong

137. The rated capacity of the transformer refers to the apparent power output by the transformer. correct

138. When using RL spiral fuse, the center contact of its base is connected to the load, and the spiral part is connected to the power supply. wrong

139. For lines with multiple motor loads, the rated fusing current of the fuse should be greater than or equal to 1.5 ~ 2.5 times the sum of the rated currents of each motor. wrong

140. Generally, for low-voltage equipment and lines, the insulation resistance shall not be less than 0.5MΩ, and the lighting line shall not be less than 0.22MΩ. correct

14 1. For lighting switches in dusty and humid places or outdoor places, porcelain waterproof cable switches should be selected. correct

142. enclosed or explosion-proof lamps should be used in inflammable and explosive places, and waterproof and dustproof lamps should be used in dusty, humid and corrosive gas places. correct

143. the electric probe is the main tool for low-voltage electricity inspection, which is used to detect the voltage of 500 v ~1000 v. wrong

144. Motors with frequent forward rotation, reverse rotation and frequent starting are suitable for thermal relay protection. wrong

145. Generally, the knife switch cannot cut off the fault current, nor can it withstand the electromotive force and thermal effect caused by the fault current. wrong

146. The primary current of current transformer depends on the secondary current. When the secondary current is large, the primary current becomes large. wrong

147. The leakage protector can't protect the two-phase electric shock, nor can it protect the interphase short circuit. correct

148. Usually, after the circuit is cut off, the parallel capacitor banks discharge by themselves through voltage transformers or discharge bulbs, so the substation can be repaired without manual discharge after power failure. wrong

149. When using1:1safety isolation transformer, its secondary terminal must be reliably grounded. wrong

150. It is forbidden to use aluminum core insulated wire for wiring in factories with inflammable and explosive hazards. correct

15 1. The specific provisions in the Electrical Safety Regulations should be flexibly adjusted according to the actual situation. wrong

152. Rubber overshoes worn in rainy days can also be temporarily used as insulating shoes during electrician operations. wrong

153. If the installation of low-voltage temporary lighting is very reliable, the power supply mode of "one line and one place" can also be adopted. wrong

154. Using 36V safe voltage can ensure that electric shock accidents will not happen again. wrong

155. Experienced electricians don't need to test with pencils after power failure. wrong

156. The danger of electric shock depends entirely on the current passing through the human body. wrong

157. The high-voltage load switch has an arc extinguishing device, which can disconnect the short-circuit current. wrong

158. During the operation of the high-voltage disconnector, if it is found that the insulator surface is seriously discharged or the insulator is broken, the high-voltage disconnector should be immediately disconnected and quit the operation. wrong

159. When the substation is out of power, pull the disconnector first, and then cut off the circuit breaker. wrong

160. Cable cores are sometimes pressed into circular, semi-circular and fan-shaped shapes. This is to reduce the overall size of the cable and save raw materials. correct

16 1. No more than 1 joints are allowed for all pipelines crossing the line. wrong

162. The wires are laid in the ceiling or suspended ceiling, and there is no need to wear pipes for protection. wrong

163. The laying height of indoor bare wires must be above 3.5 meters, and it is not allowed to be erected below 3.5 meters ... Wrong.

164. When the steel-core aluminum stranded wire is electrified with alternating current, the current actually only flows through the aluminum wire due to the skin effect of alternating current, so its effective cross-sectional area is only a part of the aluminum wire. correct

165. The safe current carrying capacity of the conductor should have different values at different ambient temperatures. The higher the ambient temperature, the greater the safe current carrying capacity. wrong

166. Insulating boots can also be used as acid, alkali and oil resistant boots. wrong

167. AC ammeter and voltmeter indicate effective values. correct

168. The length of primary and secondary wiring of electric welding machine shall not exceed 20m. wrong

169. When installing temporary grounding wire, the three-phase wire terminal should be installed first, and then the grounding terminal should be installed; Otherwise, first remove the grounding terminal, and then remove the three-phase line terminal. wrong

170. The protection terminal of electric soldering iron can be wired or not. wrong

17 1. Whether measuring DC or AC, the neon lights of the electroscope are the same. wrong

172. The greater the internal resistance of the ammeter for measuring current, the better. wrong

173. Measure the resistance with a multimeter, and reset the pointer to zero every time you change the ohm gear. correct

174. Clamp ammeter can be used to measure AC current and DC current. wrong

175. DC ammeter can be used in AC circuit. wrong

176. The secondary winding of voltage transformer is not allowed to open circuit, and the secondary winding of current transformer is not allowed to short circuit. wrong

177. The clamp ammeter can only measure the current of one phase conductor at a time. correct

178. For equipment with rated voltage above 500V, 1000V or 2500V insulation resistance meter can be selected for insulation resistance measurement. correct

179. In order to prevent step voltage from getting an electric shock, insulating boots can be used as basic safety appliances. correct

180. The connecting wire of the electrode holder on the secondary side of arc welding machine shall not be connected to zero (or grounded), and the other wire on the secondary side can only be connected to zero (or grounded) one by one. correct

18 1. Generally, the service life of temporary lines is 15 days, and it is necessary to go through the examination and approval procedures for temporary wiring devices. correct

182. If the first phase of the motor is suddenly out of phase, it should be stopped immediately for inspection. correct

183. Generally, the motor can run within the range of -5%-+ 10% of the rated voltage, and its rated output remains unchanged. correct

184. When the motor runs at rated output, the phase-to-phase voltage imbalance should not exceed 10% error.

185. When the three-phase voltage of the power supply is balanced, the deviation of the average value of any phase and three-phase current shall not exceed 5%.

186. When the drop fuse is in operation, the neutral phase should be closed first, then the windward phase, and finally the windward phase. wrong

187. Static electricity on the conductor can be eliminated by grounding. correct

188. the lightning arrester should be installed as close as possible to the transformer, and the grounding wire should be connected to the low-voltage neutral point of the transformer and the metal shell for grounding. correct

189. After the leakage protector operates, if no accident point is found, it is allowed to try to send electricity once. correct

190.TT system refers to the neutral point of distribution network and the metal shell grounding of electrical equipment. correct

19 1.IT system means that the neutral point of power supply is grounded and the metal shell of electrical equipment is not grounded. wrong

192. The working zero line should be painted green and yellow. wrong

193. The protective neutral line (pen line) should be painted with light blue at vertical intervals. correct

194. The neutral point of any star-shaped wiring equipment in use must be regarded as live equipment. correct

195. In case of power failure, the operating energy of circuit breakers and disconnectors should be disconnected. correct

196. When the maintenance equipment is powered off, the isolating switch must be opened to make at least one obvious short circuit point in all aspects. correct

197. Single-core copper wire shall be used for wiring, and the cross section meets the requirements. wrong

198. Insulating rods or gloves are not needed to assemble and disassemble the grounding wire. wrong

199. When assembling and disassembling the grounding wire, the grounding end must be connected first, and then the conductor end. correct

200. After confirming that the equipment has no voltage, the three-phase short circuit of the equipment shall be repaired immediately. wrong

For reference only! Hope to adopt!