SU116264A1 - A device for measuring and recording the angle of shear between the floods of two synchronous machines when they are working in parallel - Google Patents

Description

The proposed device for measuring and recording the shear angle between the rotors of two synchronous machines for their parallel work relates to a known type of devices of the same purpose, containing a sensor and indicator of the specified angle in the form of a voltmeter or oscilloscope.

The main feature of the proposed device, which simplifies its circuit in comparison with the known devices, is the use of a system of two connected to shafts of corresponding synchronous machines and transformer-mode single-phase selsins, one of which is equipped with a rotating stator and has field winding connected to the AC network through the discriminator.

Connecting one of the above selsyns to the shaft of a synchronous motor simulating an energy system allows the proposed device to be used to measure the angle between the emf vector. generator and voltage vector of the specified system.

FIG. I-3 are schematic diagrams of three embodiments of the device.

Single-phase selsines I and II are directly connected to the shafts of synchronous machines, one of which, for example, selysyn I, has a turning point. stator In the case of measuring the shear angle between rotors having a different number of poles, the selsyn connected to the faster engine must be rotated through a corresponding downshift.

The excitation winding of the selsyn I by: 1 draws the power from the alternating current network, which maintains constant voltage. It is advisable to use selsines of increased frequency, but selsins and normal frequencies are quite suitable.

No. 116264-2 -

If the frequency in the tested installation is the same as what is needed to power the selsins, then the entire device can be powered from the tires of the tested installation. It is desirable that the selsyns have a synchronous speed significantly higher than the machines with which they are associated.

The excitation winding of the selsyn II is connected to one of the diagonals of the circular discriminator K, D (annular phase sensitive rectifier), the second diagonal of which is connected to the network supplying the selsyn I. The magnetoelectric voltmeter V (or vibrator of the oscilloscope B with filter F) is hooked between the middle points of the voltmeter V excitation of selsyn II and shunt; 7ZZ resistance / at the input of the discriminator. If the middle point of the field winding is unavailable, then the middle point of the shunt resistance Ulg is used instead. The second variant of the device circuit, which does not require the output of the center point of the field winding, is shown in FIG. 2

The voltage at the terminals of the excitation winding of the selsyn II depends on the mismatch angle of the selsins I and II. If the selsyns are stationary or the speed of rotation is much lower than their synchronous speed, then this voltage is proportional to the cosine of the error angle;

and. „,, -. 05 By installing the rotary stator of one of the selsyns, they achieve a position in which:

where 0 / in - in / - the angle of shift between the rotors (in electric gdians), P2 - the number of pairs of poles of the tested maschina, P is the number of pairs of poles of the selsyn (usually PC 1). Wherein:

  .й «с - ®

At small shear angles: ,,,,. - QI p.

The detection of the magnitude and phase of the voltage U is carried out by a phase-sensitive circuit of the disc detector, from the output of which the rectified voltage is removed.

FIG. Figure 3 shows a variant of the measuring device in which the selsynes are made with a stationary stator, and the electric differential voltage is used to find the error angle, which is connected in the usual way.

If selsyn II is associated with a small synchronous motor, carrying a constant load or unloaded, then the angle between the emf vector can be measured when a single machine is working on a powerful network. generator and voltage vector of the energy system.

Subject invention

Claims (5)

1. A device for measuring and recording the shear angle between the rotors of two synchronous machines during their parallel operation, comprising a sensor and an indicator of the specified angle in the form of a voltmeter or oscilloscope, characterized in that, to simplify the circuit, a system of two connected with the shafts of the corresponding synchronous machines and single-phase selsins operating in the transformer mode, one of which is equipped with a rotary stator and ; / has an excitation winding connected to the AC network through a discriminator. 2. The device according to claim 1, characterized in that the angle indicator is connected between the midpoint of the shunt resistance at the input of the discriminator and the midpoint connected to the last excitation winding of the selsyn. 3. The device according to claim 1, that is, so that the angle indicator is on between the middle points of the shunt resistance on both sides of the discriminator. 4. Device on PP. 1-3, characterized in that, in order to use it to measure the angle between the emf vector. the generator and the voltage vector of the energy system, one of the selsyns is connected to the shaft of the synchronous digester, imitating the energy system. 5. Device on PP. 1-4, characterized in that, in order to use the selsyn without a rotary stator, an electric differential is applied, which is included, according to a known scheme. - 3 - # 116264 CQ ILMLGCH LLLV-l ed