DE1257278B - Probe for high voltage field measurement - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

GOIr

German class: 2Ie-36/10

Number: 1257278

File number: L 49948IX d / 21 e

Filing date: February 12, 1965

Open date: December 28, 1967

The invention relates to a field probe for measuring high-voltage direct or alternating fields technical frequencies in a room with little magnetic field.

When measuring high DC or AC voltages, particular care must be taken that no high voltage can penetrate into the measuring circuits, which are accessible to persons. This means, that special precautions, such as voltage converters, overvoltage fuses, etc., are provided must be that a clean separation of the high and low voltage divider of the measuring device cause. The difficulties in this regard are mainly in the measurement of DC voltages or DC fields. For this purpose, devices were known which with mechanical moving parts, e.g. B. rotated capacitor plates or air gap chokes, in conjunction with Hall probes work. In the first case, apart from the disadvantage of the mechanically moving parts, the ao The energy taken is so small that it needs reinforcement. In the other case, the facility removes the voltage source supplies a current to magnetize the chokes. This is above all then disadvantageous when it comes to voltage measurements on impulse current systems in which capacitors be discharged through the device in a not insignificant time.

The object of the invention avoids the disadvantages of the known devices. she can in addition, they are made so spatially small that they not only measure potential differences, but the course of electrical fields can be recorded by a simple coordinate measuring process can.

It is already known to make an electron beam constant for measurement purposes through a magnetic field Deflect frequency and amplitude (British patent 796 490).

The invention consists in that the change in the current flowing through a vacuum diode in whose anode circuit is a consumer, is a measure of the external electric field. Since this species Field probe responds equally to electrical and magnetic fields - it would in certain If the E-field is inaccurate, in the case of a predominance of Η components it may even be just that Measure magnetic field - it is necessary to achieve a sufficient measurement accuracy that they only is used in rooms with little magnetic field. In the case of alternating electric fields, it is important to ensure that these do not exhibit magnetic fields as a result, probe for high-voltage field measurement

Applicant:

Licentia Patent-Verwaltungs-G. m. b. H.,

Frankfurt / M., Theodor-Stern-Kai 1

Named as inventor:

Dipl.-Ing. Walter Langhein, Frankfurt / M.

as is the case with high frequencies. The same generally applies to the presence of ladders large currents.

The operation of the device is shown schematically by the images in FIG. 1 to 5, the mechanical Structure by the embodiment of FIG. 6 illustrates.

The principle of the field probe according to the invention is based on FIG. 1 a and 1 b.

A tube 1, which, like a vacuum diode, has only a cathode and an anode, is brought into the voltage field to be measured. When applying the anode voltage U _a a current i _a, which produces at an outer consumer R _a voltage drop. If such a tube is placed in an electric field F _a , the electron current in the diode is deflected to the right or left, depending on the direction of the field, and the anode current / ₀ decreases or becomes zero. U _h represents the heating voltage of the diode.

In one embodiment of the invention, the vacuum diode 1 according to FIG. 2 three anodes A ₁ to A ₃ , one in the middle and the other two on the side.

In the circuit example according to FIG. 2, the two anodes A ₂ and A ₃ are connected to one another and connected to the anode voltage U _ai via an external consumer R _a2 . The middle anode A _t is connected to the anode voltage U _av via the external consumer R _{a 1}

U ₀₁ is always greater than U _a2 , so that in the quiescent state with an external field strength of zero, the predominant part of the anode current flows through R _{a t} . When an external field is applied, the anode current is deflected, with a StTOmZ ₁₁₂ flowing over the left or right anode, depending on the direction of the field. When an external field - direct or alternating field - is applied, the difference compared to the idle state is that R _a2 becomes live. It can also be via R _al

709 710/210

Claims (12)

a current flow, which is however smaller than in the idle state. The conditions have thus been reversed compared to the state of rest. F i g. 3 differs from FIG. 2 in that the currents of the individual side anodes A2 and Az are recorded separately via the external consumers ίία2 and R11 a. The external consumers can be ohmic resistances, chokes or combinations of capacitances, resistances and chokes. It is also possible, as shown in FIG. 4 shows connecting a relay Ra to the anode circuits. In a further embodiment of the invention, this relay receives two windings in opposite directions. According to the circuit example, it is attracted in the idle state and drops when a sufficiently high current ia2 is exceeded. The electrical field can also be measured, as shown in FIGS. 5a and 5b: The measuring instrument R11 has a quotient system and forms the quotient iallias or the reciprocal value. A variation against Fig. 5 a forms FIG. 5 b insofar as two anode voltages Uai and Ua2 are again provided. It is also possible to measure the electric field by switching on a moving coil instrument or measuring instruments which detect the difference between the two currents. It is also conceivable to provide recording instruments for measuring the course of the field, with which the course of the field can then be recorded in one direction. By superimposing several registration strips, the field image is then obtained when the probe coordinates shift. It is also possible to measure the direction of the electrical field lines, since a change in the anode current intensity occurs when the field probe is rotated in the measuring field. In further pursuit of this possible application, the circuit example according to FIG. 5 c an application as a voltage converter for high and extremely high alternating voltages; the vacuum diode 1 with only two anodes At, A3 is for this purpose in a reproducible position to the live parts, z. B. the busbars brought. The changing field causes a changing loading of the anodes A2, A% and thus current flows through the primary windings a, b of the transformer Tr. As a result, a voltage is induced in the winding c which the instrument M measures. The resistors R, RS1 to Rg3 are used in a known manner to stabilize the measuring arrangement and reduce the drift. The arrangement described can replace expensive measuring arrangements, especially at very high voltages. Fig. 6 gives an embodiment for the construction of the probe according to the invention. Here, the measuring tube 1 is closed at the ends by an insulating tube 2 which carries a metal foil 3 in its interior. This metal foil can be connected to earth potential and has the effect that the leads are in a field-free space. Only the heating cable is led through the field for a short distance, which is of no importance in view of the low-resistance design. Patent claims: 1. Field probe for measuring electrical high-voltage DC or AC fields technical frequencies in a room with little magnetic field, indicated by that the change in the current flowing through a vacuum diode enters its anode circuit Consumer is a measure of the external electric field. 2. Probe according to claim 1, characterized in that the vacuum diode is several, preferably has three anodes. 3. Probe according to claim 2, characterized in that the two outer ones of the three anodes are connected to the anode voltage via the same or different consumers. 4. Probe according to claim 3, characterized in that the central anode has a second consumer is connected to an anode voltage that is different from the first anode voltage is different. 5. Probe according to claim 1 or the following, characterized in that the consumer is a Relay is. 6. Probe according to claim 3 or the following, characterized in that the relay has two opposing directions Owns windings. 7. Probe according to claim 1 or the following, characterized in that the consumer is a Quotient measuring mechanism is. 8. A probe according to claim 7, characterized in that the power source-side connections of the quotient measuring mechanism connected or separated at different voltage points the anode sources are guided. 9. Probe according to claim 1 or the following, characterized in that the consumer is a registering galvanometer. 10. Probe according to claim 1 or the following, characterized in that the vacuum diode has two anodes, each with a winding of a transformer in their anode circuits at the output of which a measuring or recording instrument is connected. 11. Probe according to claim 10, characterized in that the anode and cathode of the Vacuum diode an insulating tube is placed, which is lined with a metal foil. 12. Probe according to claim 1 or the following, characterized by its use for measurement the direction of the electric field. Considered publications:
German Patent Nos. 535 164, 566 286;
British Patent No. 796 490. 1 sheet of drawings 709 710/210 12.67 © Bundesdruckerei Berlin