The operation of baoding oil-immersed transformer has always been an important type of safe and operating state. For the operation of oil-immersed transformer, its stability and safety must be guaranteed. However, sometimes the operation of oil-immersed transformer is asymmetrical, which leads to the unstable operation of baoding oil-immersed transformer and causes great obstacles to the operation of oil-immersed transformer. As a result, the operation efficiency of oil-immersed transformer is slowed down, and even oil-immersed transformer has different degrees of faults. So why do oil-immersed transformers run asymmetrically? The following are the specific reasons for your reference:

1. Asymmetrical operation is caused by different three-phase loads

For example, baoding oil-immersed transformer power supply for lighting, welding and other loads, or some oil-immersed transformer power supply for electric locomotive electricity and steel furnace with single-phase nature of the load. This load asymmetry makes the three-phase current flowing through the oil-immersed transformer asymmetric, which makes the three-phase impedance voltage drop asymmetric and causes the three-phase voltage asymmetry on the secondary side. Voltage asymmetry is unfavorable to the operation of three-phase induction motor and lighting equipment. But generally speaking, the voltage asymmetry caused by the impedance of oil-immersed transformer is not large.

In this asymmetric operation, the main consideration is that the Central Line current of baoding oil-immersed transformer connected by Y/ y0-12 during operation shall not exceed 25% of the rated current of the low-voltage coil.

2. The three-phase baoding oil-immersed transformer group is composed of three single-phase oil-immersed transformers

When the phase of a three-phase baoding oil-immersed transformer group is damaged and replaced by a phase with different parameters (such as different impedance voltages or varying ratios), the current and voltage will be asymmetric.

This kind of baoding oil-immersed transformer group, when operating, not only the current of the group is asymmetric, but also other oil-immersed transformers connected with the neutral grounding wire will generate the ground current, and its available capacity is less than the sum of the capacity of the three single-phase oil-immersed transformers. The available capacity and the degree of asymmetry depend on the fit of oil-immersed transformer parameters.

3. Asymmetric operation of oil-immersed transformer is caused by asymmetric wiring

At this time, it can be divided into the following situations:

(1) two-line and one-floor system:

Baoding oil-immersed transformer is still three-phase wiring, one phase of the line by the earth to act as a conductor is called the two-wire one-ground system, China's rural power network is still a small number of this wiring method.

The capacity of oil-immersed transformer can not be reduced by this wiring method. Just because the resistance of the line and the ground are different, make voltage asymmetry. But when the voltage loss in the line is less than 10%, the voltage asymmetry is not more than 1% ~ 2%, which is allowed. If we go beyond this range, we can improve it by reducing the transmission power of the line.

There are several problems to be noted in this asymmetric operation:

(1) if there is a short circuit to the ground in one of the ungrounded phase of the wire, the grounding device due to the short circuit current will produce dangerous contact voltage and step voltage, so in the accident treatment to wear insulation shoes, wear insulation gloves;

(2) adjacent through the communication lines can be induced to dangerous voltage and interference.

(2) two-phase operation of baoding oil-immersed transformer:

In some cases, two-phase operation of baoding oil-immersed transformer is required, which also results in asymmetric operation of oil-immersed transformer. These situations are as follows: when a phase line fault occurs in a neutral grounded system, zero line is used to replace the phase temporarily; The fault of one oil-immersed transformer in the three-phase oil-immersed transformer group is temporarily operated as a two-phase oil-immersed transformer. Three - phase oil - immersed transformer one - phase coil fault temporarily in two - phase operation.

The common characteristic of this asymmetric operation is that the capacity of baoding oil-immersed transformer can be reduced to less than the sum of the rated capacity of the two-phase oil-immersed transformer still in operation. The available capacity depends on the asymmetry of the current. The reasons for the two-phase operation of oil-immersed transformer are as follows: for example, the circuit breaker on one side of the oil-immersed transformer is disconnected in one phase and the tap joints of the oil-immersed transformer are not in good contact with each other.

Asymmetry of oil-immersed transformer is running, the baoding oil-immersed transformer itself, the damage is not too big, so there is no need to like generator to limit the size of the asymmetry of three-phase current (Y/Y0-12 except wiring of oil-immersed transformer), mainly is to consider from the current voltage of asymmetric impact on users, and the communications lines along the interference and its influence on power system relay protection work conditions.

Baoding zhongyi electric material manufacturing co., ltd. is a professional transformer manufacturer in baoding transformer factory, with professional production equipment, lifting, tooling and testing equipment, established a perfect quality management system, product performance indicators have reached the standard.

The company's main products: baoding dry transformer, baoding box transformer, baoding oil-immersed transformer, baoding high and low voltage complete sets of equipment. I companies to follow "detail decides success or failure, honesty molded the future" of the enterprise purpose, adhere to "quality measuring market, seek development by innovation, to management for efficiency" business philosophy, to make my company's products are widely used in power plant, chemical, construction, mining, metallurgy, rail transportation and other industries, to meet the needs of various users, my company rely on superior product quality, thoughtful service, won the trust of our customers.