RU73493U1 - DEVICE FOR DETERMINING THE PARAMETERS OF THE D-SHAPED DIAGRAM OF THE REPLACEMENT OF THE SINGLE-PHASE TWO-WISE TRANSFORMER IN OPERATING MODE - Google Patents

Abstract

The utility model relates to the field of electromechanics, namely to the use of information processing tools in electromechanics, and can be used to approximate the parameters of the L-shaped equivalent circuit (SZ) of single-phase double-winding transformers. The objective of the utility model is to create a device for determining the parameters of the L-shaped equivalent circuit of a single-phase double-winding transformer in operating mode, which can be used for a transformer that does not have an unloaded winding. The task is achieved in that the device for determining the parameters of the L-shaped equivalent circuit of a single-phase two-winding transformer in the operating mode contains measuring transducers of the primary current and voltage connected to the primary winding of the transformer and measuring transformers of the secondary current and voltage connected to the secondary winding of the transformer. Moreover, each of the measuring transducers is connected to a series-connected switch and an analog-to-digital converter, to which a reduction unit is connected, connected to a difference calculation unit, which is connected to an actual value unit, a characteristic points unit and an active resistance unit. In this case, the effective value block is connected in series with the power determination unit and the resistance calculation unit, and the resistance calculation unit, the characteristic points block and the active resistance block are connected to the segment indicators. 1 ill.

Description

The utility model relates to the field of electromechanics, namely to the use of information processing tools in electromechanics, and can be used to approximate the parameters of the L-shaped equivalent circuit (SZ) of single-phase double-winding transformers.

No devices are known that make it possible to determine the parameters of the L-shaped equivalent circuit of a single-phase transformer that does not have an unloaded winding in the operating mode.

The objective of the utility model is to create a device for determining the parameters of the L-shaped equivalent circuit of a single-phase double-winding transformer in operating mode, which can be used for a transformer that does not have an unloaded winding.

The task is achieved in that the device for determining the parameters of the L-shaped equivalent circuit of a single-phase two-winding transformer in the operating mode contains measuring transducers of the primary current and voltage connected to the primary winding of the transformer and measuring transformers of the secondary current and voltage connected to the secondary winding of the transformer. Moreover, each of the measuring transducers is connected to a series-connected switch and an analog-to-digital converter, to which a reduction unit is connected, connected to a difference calculation unit, which is connected to an actual value unit, a characteristic points unit and an active resistance unit. In this case, the effective value block is connected in series with the power determination unit and the resistance calculation unit, and the resistance calculation unit, the characteristic points block and the active resistance block are connected to the segment indicators.

Due to the fact that the claimed device contains a reduction unit, a difference calculation unit, an effective value unit, a power determination unit, a resistance calculation unit, a characteristic points unit and an active resistance unit, it allows determining the parameters of the L-shaped equivalent circuit of a single-phase double-winding transformer in the operating mode and can be used for a transformer that does not have an unloaded winding.

Figure 1 - presents the hardware circuit of the device for determining the parameters of the L-shaped equivalent circuit of a single-phase double-winding transformer in operating mode.

The device for determining the parameters of the L-shaped equivalent circuit of a single-phase double-winding transformer in the operating mode contains four measuring transducers, each of which is connected to a switch that is connected to an analog-to-digital converter (not shown in figure 1), cast unit 1 (PSU), difference calculation block 2 (BVR), effective value block 3 (BDZ), power determination block 4 (BOM), resistance calculation block 5 (BVS), characteristic points block 6 (BHT) and resistance block 7 (BAS).

The primary current and voltage transducers are connected to the transformer primary winding, the secondary current and voltage transducers are connected to the secondary winding of the transformer, each of the measuring transducers is connected to a switch and an analog-to-digital converter connected in series (not shown in Fig. 1).

The casting unit 1 (BP) is connected to an analog-to-digital converter (not shown in FIG. 1) and to the difference calculation unit 2 (BVR), which is connected to the effective value block 3 (BDZ), characteristic points block 6 (BCH) and the block active resistance 7 (ALS). The block of effective value 3 (BDZ) is connected in series with the block for determining the power 4 (BOM) and the block for calculating the resistances 5 (BVS). The block of calculation of the resistances 5 (BVS), the block of characteristic points 6 (BHT) and the block of active resistance 7 (BAS) are connected to segment indicators (not shown in figure 1).

Reduction unit 1 (BP), difference calculation block 2 (BVR), effective value block 3 (BDZ), power determination block 4 (BOM), resistance calculation block 5 (BVS), characteristic points block 6 (BHT) and resistance block 7 (BAS) can be performed on the atmel AT89S53 series 51 microcontroller.

The device operates as follows. When a single-phase two-winding transformer is operating in close to nominal mode, through arrays, a switch, and analog-to-digital converters (not shown in FIG. 1) in the cast unit 1 (BP), as shown in FIG. 1, the arrays of instantaneous input values are recorded voltage input current output voltage output current for the same points in time.

Then, in the block of reduction 1 (PSU) form arrays of output voltage and output current, reduced to the primary circuit by the formulas:

, ,

where W ₁ and W ₂ - the number of turns of the primary and secondary windings.

After that, using the difference calculation unit 2 (BVR), the inputs of which are fed arrays , , and determine the magnetization current

and voltage drop across transformer windings

.

Further arrays of instantaneous values of the magnetization current input voltage reduced output current and voltage drops on transformer windings arrive at the input of the block of actual value 3 (BDZ), which determines the effective value of the output current

,

and magnetization current

.

Then, in the power determination unit 4 (BOM), the value of the active magnetic losses in the transformer is determined

,

value of active losses in transformer windings

,

transformer magnetization reactive power

,

Where - current-voltage characteristic area , and the value of the total power dissipation inductance of the transformer windings

Where - current-voltage characteristic area .

Next, in the block for calculating resistances 5 (BVS), the active resistance of the transverse branch of the L-shaped equivalent circuit

,

active resistance of the longitudinal branch of the L-shaped transformer equivalent circuit

,

inductive resistance of the transverse branch of the L-shaped equivalent circuit

and inductive resistance of the longitudinal branch of the L-shaped equivalent circuit

.

Arrays and arrive at the input of the block of characteristic points 6 (BHT), in which the array of instantaneous values of the reduced output current is numerically differentiated and form an array of instantaneous values of the derivative of the output current with respect to time as

.

Next, in the block of characteristic points 6 (BHT) solve the equation

,

Where - total leakage inductance of the transformer windings. To do this, select the time t ₁ when , and time t ₂ , when , the values of the active component are calculated and inductive component resistance of the longitudinal branch of the L-shaped equivalent circuit according to the formulas

; .

The average values for the period of the specified parameters are determined, which are taken as the final result

,

Where , - accordingly, the number of values , found on the period.

Then, from the output of the difference calculation unit 2 (BVR), arrays of instantaneous values and arrive at the input of the active resistance unit 7 (BAS), which determines the array of instantaneous values of the integral of the input voltage over time numerical integration of an array . In particular, the following numerical integration algorithm can be used. First find an intermediate array integral values at points whose constant component is not equal to zero. To do this, accept that . Values at other points calculated by the formula:

.

This array has some constant component. Therefore, further find an array of values of the integral at points subtracting from the array its constant component M:

,

Where - period average value of the array .

Next, determine the area characteristics of the dependence obtained on one period of the supply network. To determine this area, you can use the formula for the area of the polygon given by the coordinates of the vertices. Then

.

This area corresponds to energy losses in the transformer magnetic circuit during a time equal to one period of the supply network. Then, the power of magnetic losses in the magnetic circuit is determined by dividing the obtained area by the period of the supply network:

.

The active resistance of the transverse branch of the L-shaped equivalent circuit is determined by the formula

,

Where - the effective value of the magnetization current of the transformer.

The obtained values of the parameters of the L-shaped equivalent circuit of a single-phase double-winding transformer , , , and , , highlighted on a segment indicator not shown in figure 1.

Thus, the proposed device allows you to determine all the parameters of the L-shaped equivalent circuit of a single-phase double-winding transformer in operating mode without disconnecting from the load without an additional unloaded winding.

Claims (1)

A device for determining the parameters of the L-shaped equivalent circuit of a single-phase double-winding transformer in operating mode, characterized in that the primary current and voltage transducers are connected to the transformer primary winding, secondary current and voltage transducers are connected to the secondary winding of the transformer, each of which is connected with a series-connected switch and an analog-to-digital converter, to which the drive unit is connected I, connected to the difference calculation unit, which is connected to the real value block, the characteristic points block and the resistance block, while the rms value block is connected in series with the power determination block and the resistance calculation block, and the resistance calculation block, the characteristic points block and the active block resistance connected to segment indicators.