DE1023128B - Device serving as a direction relay - Google Patents

Description

The subject matter of the invention is a device serving as a directional relay, in particular for selective protection electrical lines is intended. The directional relays used so far for this purpose, the two-sided The lines fed in to determine the direction of the short-circuit current require considerable effort on switching contacts, so that they have relatively large dimensions and because of their susceptibility to failure require increased maintenance. Furthermore, the known directional relays are of direct current design Rectifiers for the rectification of the alternating measurands as well as smoothing means necessary for the response speed reduce such relays.

The device according to the invention serves to avoid the aforementioned disadvantages.

In the new device serving as a directional relay, a conversion of alternating quantities into constant quantities is achieved with the elimination of rectification and smoothing means which reduce the response speed according to the invention by arranging two magnetic field-dependent resistors, preferably Hall generators, in two separate magnetic fields in a manner known per se of which one is excited proportionally to the current to be monitored and the other proportionally to the ^{current shifted by 90 c} and the control currents of the two magnetic field-dependent resistors, which are proportional to the voltage to be monitored, are also phase-shifted by 90 ° with respect to one another.

There are already frequency meters based on the utilization of the Hall effect by the USA patent 2 545 369 became known, in which alternating currents with the help of two Hall elements by adding the Hall voltages of both elements are converted into direct current quantities, but here only either the Magnetic fields or the control currents of both Hall elements out of phase with each other by 90 °. It will be here only a pulsating direct current is achieved in the common Hall circuit of both Hall elements. The conversion of Alternating quantities in a completely constant electrical quantity is neither intended nor possible because it is in the known arrangement, as mentioned, is a frequency meter and not a direction relay and for generating completely constant electrical quantities in the Hall circuit according to the invention, both the magnetic fields as well as the control currents of both Hall elements 90 ° out of phase with each other.

Semiconductors with a carrier mobility of at least 6000 cm ^a / Vs are preferably used as magnetic field-dependent resistance bodies. In contrast to other known Hall voltage generators, such as germanium, for example, with a carrier mobility of about 3000 cm ² / Vs and below, the semiconductor bodies with higher carrier mobility not only have directional relays
Facility

Applicant:

Siemens-Schuckertwerke

Corporation,

Berlin and Erlangen,

Erlangen, Werner-von-Siemens-Str. 50

Dipl.-Ing. Hermann Neugebauer, Erlangen,
has been named as the inventor

the advantage of significantly greater sensitivity (greater Hall voltage with the same control variable), but must also be loaded with significantly greater output powers. It is therefore possible to directly connect measuring devices, relays or the like to the Hall voltage of such semiconductor bodies without the interposition of an amplifier. The semiconductors with such high carrier mobilities include resistance bodies made of semiconducting compounds, in particular of the form AmBv, that is to say compounds of an element A of III. Group with an element B of Group V of the Periodic Table. For the present purpose, the compounds indium antimonide and indium arsenide have proven to be particularly advantageous, in which carrier mobilities of up to 60,000 cm ² / Vs and more are achieved. Since, as explained above, the Hall voltage in these semiconducting connections can withstand a relatively high load, such Hall voltage generators are referred to as Hall generators. However, the invention is not restricted to the use of Hall generators, but also includes other Hall voltage generators. In the drawing, a schematic embodiment of the object according to the invention is explained in more detail. The arrangement shown there results in a pure direct current in the Hall circuit. For this purpose, two Hall generators 21 and 22 are arranged in two separate magnetic fields 23 and 24, of which the magnetic field 23 is proportional to the current to be monitored W ₁ = M ■ sin α and the magnetic field 24 is proportional to a current m ₂ == M · sin (α + 90) is excited, which is phase-shifted by 90 ° with respect to the current M _{1 to be monitored.} M here means the peak value of the relevant current. This phase shift can be achieved, for example, by the illustrated i? C element with the capacitor 241

709 850/342

and resistor 242 can be reached. The control currents of the Hall generators are brought in as a function of the voltage to be monitored. The control currents S ₁ = S- sin (α- β) and s ₂ = S · sin (α- β + 90) of the two Hall generators 21 and 22 are also used in order to achieve an extensive smoothing of the Hall current flowing through the control device 3 phase shifted by 90 °, for example in such a way that a capacitance 25 is connected in series with the Hall generator 22 _{in the circuit of the control current s 2.} S again means the peak value of the relevant control current and β a specific phase angle by which m _x is shifted from S ₁ or m _% from S _2.

In the Hall circuit of the Hall generator 21, the quantity corresponding to the product Wi ₁ S ₁ and in the Hall circuit of the Hall generator 22 the variable corresponding to the product m _z S _2.

According to the previous one, it follows

^m i ' ^s i ⁼ M' ^sm α * S sin (α - β)

= M S (sin ² acos / 3 - cos α sin α sin ß) and m ₂ s ₂ = M sin (α + 90) S sin (α - β -f 90)

-MS- (cos ² α cos β + cos α sin α sin β).

By connecting the two Hall circuits in series, the products W ₁ · S ₁ and m ₂ · S _{2 are} added, and a variable occurs in the control device 3

MS- (sin ² α + cos ² α) · cos β = M ■ S ■ cos β

which is constant since the peak values M and S and the phase shift cos β are constant factors.

It still has to be made up that in a practical implementation, of course, in a manner known per se a galvanic separation of control and Hall circuits is to be provided in order to avoid mutual interference.

The device according to the invention is not limited to the selective protection of electrical lines, but can be used wherever the direction of an energy flow is to be monitored, for example when delivering electrical energy from one power plant network to another.

Claims (1)

Claim: Device serving as a direction relay, in particular for the selective protection of electrical lines, characterized in that two magnetic field-dependent resistors, preferably Hall generators in on are known to be arranged in two separate magnetic fields, one of which is proportional the current to be monitored and the other is excited proportionally to the current shifted by 90 ° and the control currents proportional to the voltage to be monitored of the two magnetic field-dependent ones Resistors are also out of phase with each other by 90 °. Considered publications:
U.S. Patent No. 2,545,369;
Elektropost, 1955, pp. 113, 114. 1 sheet of drawings 709 850/342 1>.