Precautions for the hottest patrol of the distribu

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Precautions for patrolling the distribution room

when patrolling the distribution room or reading meters at the end of the month, the agricultural electrician should not only look at the appearance of the equipment or the number of the meter, but also pay attention to the following problems

1 look at the voltage indicated by the voltmeter

the normal line voltage is generally about 380V, but most of the voltmeters on the panel in the distribution room indicate 400V. But if it exceeds too much, it is not safe. If there is a voltage change-over switch on the panel, be sure to check whether the three-phase voltage is balanced or close to balance. If the voltage exceeds the allowable value, the power shall be cut off to find the cause. Open the drop fuse first, and then look at the tap changer gear. If the gear is not appropriate, adjust it to the appropriate gear, and then send the drop fuse to measure the voltage at the low voltage side. It is OK if it is normal. However, it should be noted that the gear adjustment of tap changer must be carried out when the low voltage and high voltage are all disconnected. After the gear adjustment, measure whether the DC resistance meets the requirements. However, in this case, it is best to ask the substation attendant before deciding whether to adjust the gear

2 look at the ammeter

all ammeters, especially the dynamic rubber spring fatigue testing machine, are mainly applicable to the mechanical property test load of vibrating screen rubber spring, such as endurance fatigue, fatigue life, reciprocating fatigue, message stiffness, load fatigue, also known as tensile test labor, to see whether the three-phase current is balanced or close. If it is power load, the operation state of the equipment can be seen. If there is no current in one phase, it is a lack of phase operation, and the power shall be cut off immediately for inspection and treatment. Pure lighting users may not see it during the day, but only at night. If the three-phase current difference is too large, it indicates that the three-phase lighting distribution is uneven, which will be more obvious at night. In this case, the user load needs to be adjusted on a certain day

3 switch elements in the panel

it is not enough to just look at the voltage and current. You also need to open the door of the switchboard to look at the internal components. For example, the color of busbar, circuit breaker, fuse and other equipment. If it is found that one phase, two phases or three phases are all yellow or black, and oxide layer appears, it indicates that the load is too large, which may be due to the unbalanced load of lighting users, which makes the overload output value of this phase exceed 30% (600billion yuan), or the contact is loose and has poor contact, and the power must be cut off in time

4 look at the metering device

if there is a problem with the metering equipment, it will not only cause inaccurate metering, which will cause the power supply enterprise to lose electricity, but also easy to cause disputes. Here, it is mainly to observe whether the metering device has low carbon steel caused by equipment or human factors: the sample is gradually flattened for metering. For example, check whether the lead seal at the end of the meter is intact, whether the wiring at the end of the meter is good, whether the screws of the metering transformer are loose, whether the voltage line is loose, etc

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