How to prevent the distribution transformer from b

2022-09-21
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How to prevent the distribution transformer from burning out

in Thunderstorm seasons and peak periods of power load, the distribution transformer is easy to burn out, so it is also a period of frequent accidents. How to take preventive measures to ensure the safe operation of the distribution transformer and prevent the distribution transformer from burning out is very important in daily work. The author believes that the operation management and maintenance should be strengthened from the following aspects

1 reasonably select the installation location of distribution transformer

the installation of distribution transformer should meet the voltage requirements of users, and try to avoid installing distribution transformer in barren mountains, places prone to lightning attacks and far away from residential areas, which is not convenient for regular maintenance of operators and management of staff

2 reasonable selection of the capacity of the distribution transformer

reasonable selection of the capacity of the distribution transformer is also very important, which can neither cause the overload burnout of the distribution transformer, nor cause the waste of horse and cart. The capacity of distribution transformer shall be selected reasonably according to the load of users. For example, a 100kV a distribution transformer can carry 85KW load when the power factor is 0.85

3 strengthen the measurement of power load

in the peak period of power load, the load measurement of each distribution transformer should be strengthened, and the measurement times should be increased if necessary. The distribution transformer with unbalanced three-phase current should be adjusted in time to prevent the neutral line current from being too large, which is easy to burn the lead wire and cause the user's equipment to burn out

4 avoid installing low-voltage metering boxes on distribution transformers

the low-voltage metering boxes installed on the distribution transformer station area in remote mountainous areas should be gradually removed and replaced with indoor installation as far as possible. From March, for example, when our bureau eliminated the electricity free township a few years ago, in order to facilitate management and prevent power loss, low-voltage metering boxes have been installed in remote mountainous areas. Due to long-term operation, the glass of the metering boxes is used for cooling the hydraulic system; Damaged or the low-voltage pile head of the distribution transformer is damaged and cannot be replaced in time, resulting in the damage of the distribution transformer due to the burning of the electric energy meter due to rain and other reasons

5 reasonable configuration of distribution transformer high and low voltage fuse melts

unreasonable configuration of distribution transformer high and low voltage fuse melts is easy to cause serious overload of distribution transformer and burn out distribution transformer. The configuration of high and low voltage melts should follow: ① transformers with a capacity below 100kV A should be equipped with fuses 2.0 ~ 3.0 times the rated current; ② Transformers with a capacity above 100kV a are equipped with melts 1.5 ~ 2.0 times the rated current; ③ The fuse on the low-voltage side should be configured with a slightly higher rated current

6 it is not suitable to adjust the tap changer without permission

due to the difference of electric load in winter and summer, the voltage is slightly different. In order to meet the voltage demand, some rural electricians adjust the tap changer at will without relevant tests, resulting in the tap changer not in place, causing phase to phase short circuit and burning out the distribution transformer

7 install insulating covers at the high and low levels of distribution transformers

in order to prevent natural disasters and external force damage, install high and low voltage insulating covers in residential areas and forest reserves with narrow roads when necessary to prevent the transformer from being burned out by low-voltage short circuit caused by falling things on the distribution transformer

8 lightning arresters should be installed on the high and low voltage sides of distribution transformers

lightning arresters should be installed on the high and low levels of distribution transformers in lightning prone areas. The lightning arresters are unqualified or not replaced in time in case of failure, which is easy to be attacked and burned by lightning, causing a large number of enterprises to stop receiving orders and bad transformers. In thunderstorm season every year, the lightning arrester should be sent to the repair and test department for timely installation after passing the test. Unqualified products are prohibited

9 regularly measure the grounding resistance of distribution transformer

after long-term operation (especially the grounding lead is replaced by aluminum wire), the distribution transformer has serious oxidation, and the grounding resistance increases. In addition, the corrosion and fracture of the buried grounding body cause the neutral point potential to shift. When lightning strikes or overvoltage, it is easy to cause accidents. According to the regulations, the grounding device should meet the following requirements: the grounding resistance of distribution transformers below 100kV A is not greater than 10 Ω, and the grounding resistance of distribution transformers above 100kV A is not greater than 4 Ω

10 strengthen daily management

regularly patrol the lines, cut down trees, and prevent branches from touching the conductor, causing low-voltage short circuit and burning the distribution transformer. The lack of daily management of the distribution transformer by the staff makes the transformer run short of oil for a long time, and the respirator is not installed or the silica gel is not replaced in time, which makes the distribution transformer water and damp, which is easy to cause accidents. The distribution transformer itself has quality problems. Because the distribution transformer is installed far away, some construction personnel put the untested distribution transformer into operation without authorization, temporarily using electricity, and burning the transformer

11 regularly check the low-voltage lead of the distribution transformer

it is strictly forbidden to use the wire itself as a nose and directly go up to the low-voltage pile head of the distribution transformer. Regularly check and firm the contact between the lead and the pile head of the distribution transformer to prevent burning out the low-voltage pile head of the distribution transformer due to looseness

in order to ensure the long-term safe operation of the distribution transformer and reduce the number of faults, as the operation management personnel, we must check, maintain and measure frequently, find problems in time and deal with them in time, so as to avoid the expansion of faults and burning out the distribution transformer

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