RU2279686C1 - Arrangement for definition of the group of joining of the windings of a three-phase transformer - Google Patents

Abstract

FIELD: the invention refers to electrical measuring technique and may be used for definition of the groups of joining of the windings of a three-phase transformer.

SUBSTANCE: the arrangement has a source of constant voltage and a commutative member providing by turn switching of a source of constant voltage to the outputs AB, BC, AC of the winding of the high voltage of the transformer. Besides the arrangement has additionally a digital oscillograph having a computation block, an energy independent memory, a port of conjugation with a personal computer and three measuring channels of voltage which are connected with the outputs of the winding of the low voltage of the three-phase transformer. At that the commutative member has a starting block, protection circuits of inner keys from overvoltage, an expectation block of nulling currents in the winding of high voltage of the three-phase transformer and has an additional output connected to an additional controlling input of the digital oscillograph.

EFFECT: possibility to automatically define the group of joining of the windings of the three-phase transformer, to operatively store in electronics shape the data of measurements and to document in the personal computer the data of definition of the group of joining of windings.

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Description

Technical field

The invention relates to electrical engineering and can be used to determine the connection groups of the windings of a three-phase transformer. It can be used in the energy sector during installation and commissioning of transformers. The device can be successfully used after repair of a transformer to determine the group of connection of the windings of a three-phase transformer.

State of the art

A device for determining the connection group of the transformer windings [Kutan V.M., Lagutin V.M., A.S. No. 1244604 (USSR) Device for determining groups of connection of transformer windings. Publ. in BI 1986, No. 26].

However, this device has a number of significant disadvantages. These include the manual production of switching and measurements, with different connections of the transformer windings, the need to perform different measurement schemes, the need to compare the results with the data of the well-known table.

A device is known for determining the connection group of transformer windings, comprising a rectified voltage source and a battery operating in parallel, a voltage converter, capacitor, buttons for charging and discharging a capacitor, high voltage and low voltage transformer windings, a deviation signal sensor, a register, a decoder, an indication unit [Kutin V.M., Lagutin V.M., Koval O.P. A device for determining groups of connection of transformer windings // Electric stations, 1988, No. 4].

However, this device also has several disadvantages. These include the mandatory fulfillment of certain conditions, the non-compliance of which does not allow to obtain the desired result. So, when connecting the windings of the transformer Δ / Y, the positive pole of the source must be supplied to the terminals of the phases "B", and the negative to the terminal of the phase "A" of the HV windings of the power transformer, when connecting the windings of the transformer Y / Y and Y / Δ, it is additionally necessary to install a jumper between conclusions "A" and "C", and in the case of Δ / Δ - between "B" and "C". In addition, the device is difficult to maintain because requires periodic removal of the battery and the use of an additional charger to charge the battery. The measurement process is not fully automated.

It is also known a device for determining the group of connections of the windings of power transformers, containing a rectified voltage source, one of the terminals of which is connected to one of the terminals of the high-voltage winding of the transformer, for example phase "B", and the second to the combined terminals of the other two phases of the high-voltage winding of the transformer, in particular to "A" and "C" there is also a dial indicator, which is alternately connected to two pairs of phases of the low-voltage winding of the transformer [Prikhodko VM, Kravchenko AM, Prikhodko AM A universal device for optimizing inspections of power transformers // Industrial Energy 1995, No. 4].

However, in this device, the definition of the transformer connection group is carried out after comparing the measured data with the group index table, the measurement process itself is not automated.

Closest to the proposed device is a device for determining the connection group of the windings of a three-phase transformer, containing transformer windings, a voltmeter, a galvanometer, connecting wires and switches. The definition of the connection group using this device is as follows. The dc voltage source is alternately connected to the terminals of the high-voltage winding of the power three-phase transformer and the voltage is monitored with the voltmeter, and the deviation of the galvanometer arrow is recorded at the terminals ab, bc, and ac of the low voltage winding at each moment of connection. The connection group of the windings of a three-phase transformer is determined after comparing the resulting combination of deviation signs with the combination given in the table of connection groups. [Collection of teaching aids for monitoring the state of electrical equipment. Section 2. Control methods for power transformers, autotransformers, shunt and suppressor reactors. ORGRES, M .: 1997. S. 98].

The disadvantage of this device is the manual measurement, the complexity of the process of determining the connection group of the windings of a three-phase transformer at substations in operating conditions, as three experiments and nine measurements are carried out. Then, the obtained data are used for comparison with the values of the table pointer in order to determine the connection group manually.

A common drawback of the above devices is the handwritten protocol, the inability to automatically document the measurement process and determine the connection group of the windings of a three-phase transformer on a personal computer.

SUMMARY OF THE INVENTION

The objective of the invention is the creation of a device that allows in an automated mode to determine the connection group of the windings of a three-phase transformer and having the ability to quickly save electronically the measurement data in non-volatile memory and document on the personal computer the data of the determination of the group of connection of the windings.

The problem is solved due to the fact that in the device for determining the connection group of the windings of a three-phase transformer containing a constant voltage source and a switching body, which provides alternating connection of a constant voltage source to the terminals AB, BC, AC of the high-voltage winding of the transformer, a digital oscilloscope containing a computing unit is additionally included , non-volatile memory, a port for interfacing with a personal computer and three measuring voltage channels that are connected to the outputs of the low-voltage winding of a three-phase transformer, and the switching body contains a start block, circuits for protecting internal keys from overvoltage, a unit for waiting for currents to be reset in the high-voltage winding of a three-phase transformer, and has an additional output connected to an additional control input of a digital oscilloscope.

Brief Description of the Drawings

Figure 1 shows the structural electrical diagram of the proposed device. The device contains a constant voltage source - 1, a switching body - 2, and a digital oscilloscope - 3, which are connected to the low voltage terminals of the winding of a three-phase transformer - 4.

Figure 2 illustrates the three steps of determining the 12th group of connection of the transformer windings connected according to the scheme "Y / Y".

Disclosure of invention

By the signal of pressing the button, the switching body (2), using a three-channel electronic switch, connects a constant voltage source (1) to the terminals of the AB high-voltage winding of a three-phase transformer (4). At the same time, the trigger unit of the switching body (2) supplies the control signal of the registration to the control input of the digital oscilloscope (3). A digital oscilloscope (3) starts recording three voltages in the non-volatile memory from terminals a, b, and from the low-voltage winding of a three-phase transformer (4). After the lapse of time, the switching body (2) disconnects the constant voltage source (1) from the terminals of the AB high-voltage winding of the transformer (4), while the current of the high-voltage winding of a three-phase transformer with high inductance is closed by the diodes of the switching body. Diodes and surge suppression elements on a three-channel electronic key act as circuits for protecting internal keys against overvoltage. Next, the switching body (2) removes the start signal from the control input of the digital oscilloscope (3) and then expects the currents to zero in the high-voltage winding of the three-phase transformer (4). This ends one of the three cycles of recording three voltages from the terminals of the low-voltage winding and the signal from the control input of the digital oscilloscope.

After reducing the current to zero in the high-voltage winding of a three-phase transformer (4), the switching body (2) is ready to connect the poles of the constant voltage source (1) to other pairs of terminals of the test object. During the next two cycles, similar switching of the DC voltage source (1) to the terminals of the aircraft and AC high-voltage winding of a three-phase transformer (4) is performed. Accordingly, the signals are fed to the control input of the digital oscilloscope (3), three voltages are recorded from the terminals of the low-voltage winding of the three-phase transformer (4) and the DC source (1) is turned off with a time delay until the currents are reset.

After completing three cycles, the computing unit of the digital oscilloscope, comparing the signs and signal levels from the terminals of the low voltage winding of the three-phase transformer with the table values of the groups of known connections, determines the connection group of the windings of the test object.

Further, the data and results of calculations via the serial port registered in non-volatile memory can be transferred to a personal computer.

Claims (1)

A device for determining the connection group of the windings of a three-phase transformer, containing a constant voltage source and a switching body, providing alternating connection of a constant voltage source to the terminals AB, BC, AC of the transformer high voltage winding, characterized in that it also includes a digital oscilloscope containing a computing unit, non-volatile memory, a port for interfacing with a personal computer and three voltage measuring channels that are connected to the winding terminals izkogo voltage three-phase transformer, wherein the switching member includes a start block, internal keys overvoltage protection circuit, the standby unit nulling currents in the high voltage winding and three-phase transformer has a second output connected to an additional control input of a digital oscilloscope.

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