DE432837C - Device for high-voltage systems for displaying a short-circuit in alternating current devices and machines - Google Patents

Description

GERMAN EMPIRE

ISSUED ON
t4. AUGUST 1926

REICH PATENT OFFICE

PATENT LETTERING

M 432837 CLASS 74b GROUP

(E32384 VIIIj ₇₄ b)

Patented in the German Empire on April 19, 1925.

Up to now it has only been imperfectly possible to close a generator against a shorted turn protection. The only previously known invention of the support throttle uses the The fact that the star point of a star-connected core transformer is always in the The center of gravity of the tension triangle falls. This device must be used with unbalanced Either address the load, but none anyway

ίο There is an error, or must be so insensitive be set so that they have a conclusion between a few turns of the same Phase can no longer grasp.

In contrast to the above method, the sensitivity in the present invention, in which the electromotive forces of the individual phases are compared according to their size, thereby increasing at will that highly sensitive relays are used in connection with converters corresponding Power. The greater the power of the voltage transformer and the current transformer is selected and the higher the sensitivity of the relay, the greater the sensitivity of the protection.

The circuit diagram is shown in Fig. I. Here / means a current transformer set that works on an auxiliary transformer V. S is a voltage converter, W is a transformer or a choke coil for operating an interturn fault relay designated by R.

The transformer W consists of three single-phase transformers or a four-leg or five-leg transformer. Instead of the three-phase secondary winding in a delta connection according to Fig. Ι, a single-phase

*) The patent seeker stated as the inventor:

Dr. Bütoip in Frankfurt a. M.

Winding on the fourth or fourth and fifth leg according to Fig. 2b can be used to operate the relay R. The relay can also be built into the zero point connection between S and W as shown in Fig. 2a.

The device intended only for high voltage systems operates as follows: j

In Fig. 3, the terminal voltages that are ίο by the converter 6 "(Fig. I) is denoted by V. When the currents / in ^the! Individual phases flow, the V _s voltage drops indicated in Fig. 3 are formed. 'The geometric addition of the terminal voltages V and the voltage drops V _s gives the electromotive forces E. As long as the generator is in order, the sum of the three electromotive forces E must be zero. the sum of the electromotive forces is different from zero; a current must therefore flow through the relay which causes the relay to respond. The sensitivity of the relay can be increased as much as desired for the reasons given earlier To avoid frequency, it is advisable to connect the capacitors labeled C in Fig. 1 and 2 in series with the relay R. The capacitors are to be chosen so that they work in resonance with the relay at the operating frequency, which at the same time significantly increases the sensitivity.

All transformers used in this circuit must, of course (TEL Man- \ ₄ ", four or five legs transformer) i as either single-phase or as having magnetic yoke are executed.

The invention can be used in all alternating current networks, including single-phase and multi-phase currents. It can be used in generators, transformers, motors, resistors, chokes, capacitors, etc. come dung.

In order to avoid overloading the relay, the arrangement sketched in Fig. 4, which can be applied to any relay, can be used. Therein w means a series resistor, e.g. B. iron resistance, R the relay, r another resistor and η two voltage fuses, z. B. neon tubes. This device works as follows:

As soon as the voltage at the relay becomes too high, the neon tubes respond. Since the response of these fuses means a complete short circuit, the resistor r is connected upstream, so that the relay is not completely de-energized, but still contains a current that is sufficient to trigger. The resistor w avoids a complete short circuit of the transformer. The neon tubes respond at around 80 volts and then let through any amount of current. In contrast to the fuse, they have an infinitely high resistance as long as they do not respond. If the voltage drops below about 80 volts (the response voltage), the breakdown fuses, unlike the fuse, are ready for operation again. If the relay is overloaded, a shunt is connected in parallel to you, consisting of the neon tubes η and the resistor. The relay remains ready for operation and responds despite the shunt.

Claims (3)

Patent Claims: ι. Apparatus ines for high-voltage systems for displaying% shorted turn for AC apparatuses and machines, characterized in that (o generator. The like.) In series with the protected apparatus, a set of current transformers (7) and parallel to the protected apparatus, a set of voltage transformers (s ) g _{0 is} built in, so that the electromotive forces of the individual phase are compared according to their magnitude and the electromotive forces that occur in them cause a highly sensitive relay (R) to respond, which therefore indicates that one is zero different sum is available. 2. Apparatus according to claim 1, characterized in that the through the Current transformer (7) generated voltage added to or subtracted from another will. 3. Apparatus according to claim 1, characterized in that a gas-filled spark gap (neon or helium tube n) in series with a resistor (r) is parallel to the relay (R) , whereby the parallel connection can, under certain circumstances, also take place with the interposition of a small transformer. 1 sheet of drawings.