Modern human life is unthinkable without electricity, which has greatly expanded the boundaries and possibilities of our existence. To fully satisfy their own needs, electric energy must have a number of quality indicators. The dominant of them is considered to be the voltage that is regulated using the transformer ansapf. What kind of functional element of the power equipment is and how it works, we will understand further.
What is anacapf: definition and purpose
Ansapf transformer is a PBB switch located on the higher voltage side. Designed to adjust the transformation ratio. In a simple sense, the process involves changing the number of turns in the winding, which, according to physical laws, corrects the magnitude of the voltage.
A similar element allows you to change the voltage level by +/- 10%. The level depends on the power of the power equipment, its technical features. Adjustment of the transformer 10 / 0.4 kV transducer is carried out only when the equipment is taken out for repair (switching without excitation).
It is not possible to make adjustments at any convenient time, since the operation requires de-energizing the subscribers. That is why, on powerful transformers of power substations from 110 kV and higher, another device is used, called on-load tap-changer.
Adjustment of voltage under load is considered an improved ansapf, which allows you to change the number of turns without shutting down. For the convenience of observing modes by dispatching personnel, the on-load tap-changer is complemented by telemechanics.
Ansapfi device
Anzapf transformer is a simple device in the form of a round connection, which is coupled with a switch and a winding on the high side. Correction is performed in two directions: increase (decrease) and decrease (add). All this is characterized by the physical law of Ohms, which suggests a proportional ratio of resistance to voltage level.
To understand in what position the transformer ansapf is, you need to look at the legend of the nameplate. Each step involves a change of 2.5% in the direction of decrease or increase. To maintain the stability of the contact resistance, a spring device is used.
Note that over time, the insulation resistance may decrease, so the device must be transferred at least 2 times a year. Once a year, physical measurements of the windings should be carried out using a megger or other insulation service devices.
Circuit diagram
Schematic representation of ansapfa is presented below. Some transformers may differ in position and direction of movement, other parameters remain unchanged.
On-load tap-changer: principle of operation
As noted above, the adjustment of the transformer ansapf can be performed through the on-load tap-changer. A special type of switching involves constant voltage adjustment depending on the time of day and load. Regulation is carried out in the range from +/- 10 to 16%. In some cases, a fully automatic mechanism is installed that supports the desired mode of operation on its own. Other options depend on the operational control from the control room or the control room .
As for the principle of work, it is made as follows:
- There is an ansapf, which, by unscrewing the spring, changes the number of windings. Under normal conditions, 33 turns implies a change in the number of turns per unit. The regulatory measure is largely determined by the detuning step.
- To automate the process, a mechanical motor is connected, which is detuned to perform exactly one operation. From the OPU, a signal is supplied to the electric motor, after which regulation takes place.
- For a faster response, it is necessary to use telemechanics, which provides the process from the control room.
Types of on-load tap-changer
There are several types of voltage adjustment, among which stand out:
- On-load tap-changers with current limiting reactors. This is an ansapf of an old-type transformer, which assumes the presence of two contactors and a reactor. During the operation, two contacts are short-circuited until they switch to another position. A reactor is used to limit the negative impact.
- On-load tap-changer with limit resistors. It is applied at new transformer substations. The trigger contactor is involved in the method, which involves changing the number of turns through the spring. This reduces the voltage level transformation time and the negative effect on the equipment.
On-load tap-changer and telemechanics: voltage correction automation
Switching the transformer ansappa is an extremely important procedure, especially for substations from 110 kV and above. As noted earlier, the process involves the on-load tap-changer, the switching of which can be displayed on the dispatcher's console. For this, telemechanics are used, which can send a signal to increase or decrease the voltage level via a fiber-optic cable.
The general scheme assumes the following elements in the chain:
- The presence of a server room that sends and receives a signal to the substation, as well as a computer in the control room. Information transfer involves the use of a conductor, where fiber is most often used. Twisted pair cases are also common here, but the speed of information transfer is significantly inferior.
- At the substation in the telemechanics cabinet, the cable is connected to the unit that interacts with the on-load tap-changer. At the output, there are two types of increase / decrease commands. After the operation, a response is given to the server, which manifests itself in the execution or non-execution of the task.
- To determine the voltage level, telemetry is output to the computer. When adjusting, the latter should change up or down depending on the signal sent.
Automation and telemechanics provide significant comfort in the conduct of regime instructions. Building a system largely depends on the technologies and equipment used. It should be noted that building an automated work system is the next step in the comfortable regulation of the mode according to the schedule.
Video: on-load tap-changer mechanical work
We suggest watching a video in which the mechanics of the on-load tap-changer are presented. Specialists calibrate the adjustment under voltage, counting the number of completed revolutions.
Conclusion
Ansapf transformer is an element of a power transformer that allows you to adjust the voltage level. The device has a simple mechanism of action based on Ohm's law of resistance. The general principle of adjustment involves changing the number of turns of the winding, but the process is carried out with the redemption of the WSP or without it through the on-load tap-changer.
The choice depends on the power equipment, its power and some other features. The adjustment of the ansapf of the transformer 10 / 0.4 in most cases is carried out only with repayment. For high-voltage substations, where it is assumed that a large number of subscribers lack power, on-load tap-changers are used. The quality of electric energy largely depends on such a simple device, which was discussed in the presented article.