SU67766A1 - Device for determining the dielectric loss angle of electrically insulating materials - Google Patents

Description

Prevention of accidents with high-voltage equipment is practically inconceivable without systematic measurements of the dielectric loss angle (tgS).

Existing measurement methods (tg) are available only to large energy systems due to the complexity, high cost and scarcity of the instruments needed for these measurements (Schering Bridge, astatic sensitive wattmeter).

The proposed device for measuring the dielectric loss angle does not have these disadvantages. In it, the determination of the dielectric loss angle is carried out by comparing the capacitance of a capacitor, the dielectric of which is the material under investigation, with two capacitance mirror galvanometers with the capacitance of a reference capacitor. The invention consists in using a synchronously rotating mirror screw or similar mechanism for scanning on a fixed screen of light rays reflected from mirrors, galvanometers, so that by the angle between the images of the rays on the screen it is possible to judge the angle of phase shift between currents

flowing through the reference and test capacitor.

The foregoing is illustrated in FIG. in fig. 1 shows an electrical measurement circuit, FIG. 2 is an explanatory diagram and a ka. FIG. 3-scheme of the device.

In the diagram of FIG. I marked:

T-high voltage transformer; Ce - reference air condenser; Cx - tested equipment (bushing, etc.); FI and A-mirror vibration galvanometers.

FIG. 2- the voltage vector of the transformer, / cf is the vector of current flowing through Cx, and the FE-vector of current through Ce.

The course of galvanometer beams is shown in FIG. 3. Here:

ZV is a mirror screw, which is a mirror plate, twisted around its vertical axis at an angle in geometrical degrees, equal to the measured angle of current shear in electrical degrees. For the case of measuring dielectric loss angle, this angle (equipment rejection) is about 3 °.

- 2 -

No. 67766 rotation of the mirror screw. It is powered by the same network as the high voltage transformer. G and A - mirror vibrating galvanometers. L - lamps of galvanometers. E is a transparent (matte) screen with a vertical (parallel to the axis of rotation of the mirror screw) line. The measurement of the phase angle of the currents is performed as follows: 1) the rays of the disconnected galvanometers G, and Ha (their zero positions) are directed to the vertical axis of the mirror screw; 2) the inclination of the galvanometer A in the plane passing through the vertical axis of the mirror screw and the mirror of the galvanometer, set the beam A to the zero points; 3) start the synchronic motor and turn on the galvanometer A; turning the motor (and the mirror screw) around the vertical axis, as well as moving the screen, combine the reflection of the beam at the moment current passes through zero with a vertical line on the screen; 4) then include G, and the inclination of the galvanometer moves the plane (fan) of its beam along the scale until the reflection of the zero position of the beam L coincides with the vertical line of the screen; 5) the position of the plane (fan) of the beam G on the mirror screw's dial gives the magnitude of the slip angle of the currents in the reference capacitor and the tested capacitance (structure, apparatus). The proposed device has the following advantages: tsipu; cytine instruments and calibrated resistances, like those of the Schering bridge; calibration by test stations and laboratories of medium energy systems (power supply sections); optical method and simple geometric construction; measure without calculations. This angle (time) phase shift currents can be applied to measure the power factor and other purposes. dielectric losses of insulating materials by comparing two capacitance capacitance capacitance containers, the dielectric of which the material under study serves, with a reference capacitor capacity, which uses a synchronously rotating mirror screw or the like to scan the stationary screen of reflected light from the mirrors of the galvanometer, so that the angle between the images of the rays on the screen can be judged on the phase angle between the currents flowing through the reference and investigated capacitors. 1) measurement according to the gauge principle; 2) the absence of special definitions; 3) the ability to manufacture; and 4) the ease of checking the calibration; 5) direct reading of the result from the described device with a scan.

FIG. 2

7 "7m.

50 her

FIG. 3