The operating environment of the 10kV distribution line is complex, so it is easily affected by the outside world, and the disconnection fault occurs. Therefore, it is particularly important to strengthen the detection of the disconnection fault of the 10kV distribution line, which is directly related to the operation level of the entire power grid, in order to ensure 10kV distribution. The safety of the electric line operation, this paper will start from the cause of the 10kV distribution line disconnection failure, and deeply study the detection and positioning technology of the 10kV distribution line disconnection fault for the relevant practitioners to learn from.

1. Reasons for disconnection failure of 10kV distribution line

1.1 Mechanical external damage

As the process of urbanization continues to deepen, more and more engineering projects are approved. During the construction of the project, it is inevitable that excavation and blasting operations will be involved. Especially in the construction of municipal pipelines, earthwork excavation will be used in large quantities. Blasting technology, which will affect the normal use of 10kV distribution lines to a certain extent, even under the action of external forces, causing 10kV distribution line disconnection failure. In addition, improper operation may also cause 10kV distribution line disconnection failure. Due to insufficient level, many construction workers did not follow the construction plan, which caused the 10kV distribution line to be damaged by mechanical external force. This situation is not uncommon.

1.2 Impact of the grid operating environment

The operating environment of the 10kV distribution line is relatively harsh. At the same time, it is also affected by the local geological conditions, which restricts the stability of the 10kV distribution line to a certain extent. Especially in the harsh environment, the 10kV distribution line is extremely vulnerable to heavy rain or The impact of natural factors such as lightning strikes leads to disconnection failure of the 10kV distribution line and affects the normal power supply of the 10kV distribution line.

1.3 electrical quality problems

In addition, the operation of the 10kV distribution line is also affected by its own quality. If there is a quality problem in the 10kV distribution line, for example, the 10kV distribution line has wire material problems and insulation problems, which may lead to more serious consequences. Before the 10kV distribution line is used by the staff, the quality of the 10kV distribution line is strictly monitored to prevent the 10kV distribution line with quality problems from being used in the distribution network, which affects the stability of the line operation.

1.4 Unreasonable design and installation

Unreasonable design and installation are also important reasons for the disconnection failure of 10kV distribution lines. Due to the lack of corresponding investigations, the design of 10kV distribution lines will be unreasonable. In the construction of 10kV distribution lines, the design work will be carried out. The very important role will directly affect the operation level of the 10kV distribution line. The design work has a far-reaching impact on the direction of the 10kV distribution line and the 10kV distribution line. Therefore, the relevant staff are carrying out 10kV distribution. When designing electrical circuits, more care needs to be taken to avoid unreasonable design.

2, 10kV distribution line disconnection fault detection

2.1 Single-phase disconnection fault detection

In the event of a disconnection fault in the 10kV distribution line, the maintenance personnel should judge the nature of the 10kV distribution line disconnection fault by detecting the voltage on both sides of the fault point. If the voltage on the power supply side of the 10kV distribution line fault point rises, It can be determined that a single-phase disconnection fault has occurred in the 10kV distribution line. The most obvious feature of the single-phase disconnection fault is that the voltage on both sides of the fault point is unbalanced, the voltage on the power supply side will rise, and the voltage on the other side will decrease. It is about one-half of the original voltage. This is because the flow direction of the negative sequence current is opposite to the flow direction of the line current. Therefore, the single-phase disconnection accident will affect the power supply on the other side of the power supply. After determining the single-phase disconnection fault of the 10kV distribution line, the relevant personnel should promptly eliminate the 10kV distribution line disconnection fault and restore the power system to normal operation.

2.2 Multi-phase disconnection fault detection

The cause of the failure of the 10kV distribution line is mainly reflected in the change of current and voltage at the fault point. If the voltage on the power supply side rises to the original voltage level, the voltage on the load side will drop to one-half. The personnel can judge that the 10kV distribution line disconnection fault is a multi-phase disconnection fault. If it is a single-phase disconnection accident, the current on the power supply side will not affect the 10kV distribution line, but the multi-phase disconnection fault will affect According to this principle, the relevant personnel should speculate on the fault nature of the 10kV distribution line and take corresponding measures to speed up the troubleshooting efficiency of the 10kV distribution line.

3. Key points of positioning technology for 10kV distribution line faults

3.1 Measuring the length of a 10kV distribution line

In order to improve the accuracy of the 10kV distribution line positioning technology, the length of the 10kV distribution line must be measured. The relevant staff should use instruments with good performance during the measurement process and record the data. Usually, the low-voltage pulse method is used to measure the length of the 10kV distribution line. Not only can the length of the 10kV distribution line be accurately measured, but also the normal use of the 10kV distribution line is not affected. It is a conventional 10kV distribution line detection. method.

3.2 10kV distribution line fault point detection

10kV distribution line fault point detection is an important part of 10kV distribution line positioning technology. There are many detection methods for 10kV distribution lines. Relevant workers need to start from the actual situation of distribution network and scientifically select 10kV distribution line fault point detection. Ways to improve the accuracy of fault detection at 10kV distribution lines. Break detection is a common method of detecting fault points. Maintenance personnel check the voltage value at each line node by dividing the 10kV distribution line into extremely short. This 10kV distribution line fault point detection method can be quickly The fault location can be located, and the voltage of each fault point can be detected in real time, which provides a basis for the subsequent work of the relevant staff. It is necessary for the relevant staff to note that the method used for single-phase disconnection fault detection and multi-phase fault detection is also different. When performing single-phase disconnection fault investigation, the relevant staff should pay attention to the negative sequence on both sides of the fault point. The change of current, because the current of single-phase disconnection fault flows along the line to the power supply, so the voltage value of each fault point is collected, and the fault location can be accurately located, so that the relevant staff can quickly locate the fault point. deal with. In the detection of fault points of multi-phase disconnection faults, it is necessary to pay attention to the changes of voltage and current on both sides of the fault point. The voltage on the power supply side has symmetry. Therefore, once a multi-phase disconnection fault occurs, it will be directly reflected in At the voltage of the fault point, the voltage on the load side is asymmetrical, and the current will also change greatly, and the relevant staff can find it during the test.

3.3 Accurate positioning of 10kV distribution line disconnection faults

The cutting test technology and the pulse current method are common positioning methods for 10kV distribution line disconnection faults. In the actual detection and positioning process, there are certain errors. Therefore, relevant personnel should use technologies such as releasing audio signals as auxiliary positioning. Methods. First of all, the relevant staff should carry out rough positioning of the fault point of the 10kV distribution line, find the position of the fault point within a certain range, then apply high voltage pulse current to it, and measure the power supply resistance at both ends of the line with professional instruments, so that Accurate positioning of the 10kV distribution line disconnection fault point. Before final positioning, the relevant staff should pay attention to take protective measures to avoid damage to the 10kV distribution line during the precise positioning process.

In summary, the disconnection failure of the 10kV distribution line will affect the normal operation of the power system. Therefore, the relevant personnel should proceed from the actual situation and adopt different positioning technologies according to the nature of the fault point of the 10kV distribution line. Find the fault point of the 10kV distribution line and eliminate the broken line fault.