CN1182639C - Potential transformers for medium or high voltage circuit breakers - Google Patents

Abstract

A voltage transformer for a medium-voltage or high-voltage circuit breaker, in particular a gas-insulated medium-voltage circuit breaker, wherein the voltage transformer is arranged within the range of a medium-voltage or high-voltage connection. The feature of the present invention is that the voltage transformer is realized by connecting two independent resistors as a voltage divider (R1, R2) in series, and its input terminal is connected to the inner tapered plug (KS) via a primary interface (PS) ) is connected to the contact terminal (KA), and its output terminal is connected to the plug-in measurement terminals (M0, M1, M2) through a secondary interface (SS). Said voltage divider (R1, R2) is housed in a corrosion-resistant metal housing (MG) and is completely surrounded within the metal housing (MG) by a solid insulating encapsulation material (F1). The corrosion-resistant metal casing (MG) is fixedly connected to the measuring contacts (M0, M1) conducting zero potential. This device is used for measurement purposes of circuit breakers.

Description

Potential transformers for medium or high voltage circuit breakers

technical field

The invention relates to a voltage transformer for a medium-voltage or high-voltage circuit breaker, especially a gas-insulated medium-voltage circuit breaker, wherein the voltage transformer is arranged within the range of a medium-voltage or high-voltage interface.

Background technique

This potential transformer shown above is disclosed in German patent application specification DE 3709943. The cable gland in it is surrounded by an insulator, inside which there is an internal electrode. A capacitive voltage measuring device is realized in that a measuring electrode is arranged between the inner electrode and a conductive outer layer at zero potential, with which electrode the voltage difference between the cable connection and ground potential is measured. No special requirements can be placed on the accuracy of the measured value of this structure, because this voltage measuring device can only display the state of no voltage or voltage.

In addition to capacitive voltage measuring devices, there are also known inductive voltage measuring devices in which, for example, a toroidal core coil is used which surrounds the housing of the device. The voltage converter in the form of a transformer can be directly plugged into the medium-voltage circuit breaker in the same way as the cable gland.

In addition, resistive voltage dividers with a fixed support structure and metal-encapsulated resistive voltage dividers with high-voltage terminals are known, which are arranged in the gas connection of gas-insulated medium-voltage circuit breakers. The outside of the chamber adopts a detachable connection. Among them, the high-voltage terminals adopt the inner tapered equipment terminals specified in Part 4 of the German Industrial Standard DIN 47636. However, this high-voltage terminal can only withstand a maximum voltage of 24kV.

Contents of the invention

The technical problem to be solved by the present invention is to provide a voltage transformer for a medium-voltage or high-voltage circuit breaker, especially a gas-insulated medium-voltage circuit breaker, which has a higher Pressure resistance performance, and the structure is greatly simplified, the manufacturing cost is reduced, and at the same time, it can fully meet the current safety standards on contact safety in this technology.

The above-mentioned technical problem is solved by a voltage transformer for a medium-voltage or high-voltage circuit breaker, in particular a gas-insulated medium-voltage circuit breaker, which is arranged in the range of a medium-voltage or high-voltage connection, wherein:

1.1 The voltage transformer is realized by connecting two independent resistors as a voltage divider in series. Its input terminal is connected to the inner tapered plug and the contact terminal through a primary interface, and its output terminal is connected to the contact terminal through a secondary interface. The plug-in measurement terminals are connected,

1.2 said voltage divider is mounted in a corrosion-resistant metal enclosure and is completely enclosed within the metal enclosure by a solid insulating encapsulating material,

1.3 The corrosion-resistant metal shell is fixedly connected to the measuring contact that conducts zero potential.

Using two independent resistors connected in series to replace the capacitive or inductive voltage transformer usually used in this technology, the resulting voltage transformer has a simple structure and low cost, and it is installed in a corrosion-resistant metal shell at zero potential , with absolute contact safety.

The input end of the voltage divider is connected to the inner tapered plug with contact terminals at the primary interface part, and the secondary interface part at the output end contains a resistance lead, and the plug-in measurement terminal is drawn from the entire resistance connected in series, the The structure is easily plugged from the outside on the primary conductor encapsulation. Measurement processes can therefore be carried out on gas-insulated medium-voltage circuit breakers at any time without special measures and without risk. The individual resistors are designed according to the electrical loads that may occur.

The essence of the invention is that the inner cone plug system, which is known per se, can be used not only in conventional transformer-type voltage transformer technology, but also innovatively in resistance-type voltage transformer technology.

The feature of a kind of advantageous structure of the present invention is:

2.1 The voltage divider described is installed in a commercially available housing conforming to standard DIN 47637 part 4 and having plug terminals.

So-called commercially available housing is for example the housing described among DE 4408818 C1, and it has the plug connection device as described in DE3538193 C2. The particular advantage of this construction is that the voltage transformers are installed in the known metal housing with internally conical plug connections, which were previously only used for voltage leads on outdoor terminal blocks, so can be used without structural changes The same connection elements are mounted on resistive voltage dividers and integrated in the circuit breaker. This internal cone plug system can also be used flexibly inside the circuit breaker.

Description of drawings

The present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

Figure 1 shows the voltage transformer and its basic components.

Detailed ways

The voltage transformer includes two independent resistors connected in series as voltage dividers R1, R2, which resistors are installed inside the metal casing MG. The space between the voltage divider R1, R2 and the metal case is sealed with solid insulating packaging material F1. The corrosion-resistant metal housing MG has a primary connection PS which includes a conical plug KS with a contact terminal KA. In addition, a secondary interface SS is provided on the metal housing MG, on which measuring terminals M0, M1, M2 are provided. As shown in the figure, the measurement terminal M0 is at zero potential, and it not only communicates with the metal casing MG, but also communicates with the measurement terminal M1. By this measure, the metal housing MG has sufficient contact safety.

Measuring terminal M2 forms the resistance terminal of voltage divider R1, R2, at which terminal a voltage difference is simultaneously generated, which is the difference between the zero potential and the operating voltage applied to the circuit breaker.

In this embodiment, the voltage transformer can be plugged into the outdoor terminal of the circuit breaker like a cable connector, or plugged into the range of the busbar through a commercially available plug interface.

Claims (3)

1. A voltage transformer for a medium-voltage or high-voltage circuit breaker, wherein the voltage transformer is arranged within the range of a medium-voltage or high-voltage interface, characterized in that: The voltage transformer is realized by the series connection of two independent resistors acting as a voltage divider (R1, R2), the input of which is connected via a primary interface (PS) to the inner tapered plug (KS) and the contact terminal (KA ), its output terminal is connected to the plug-in measuring terminals (M0, M1, M2) via a secondary interface (SS), said voltage divider (R1, R2) is housed in a corrosion-resistant metal enclosure (MG) and is completely surrounded within the metal enclosure (MG) by a solid insulating encapsulation material (F1), The corrosion-resistant metal casing (MG) is fixedly connected to the measuring contacts (M0, M1) conducting zero potential. 2. The voltage transformer as claimed in claim 1, characterized in that, The voltage divider (R1, R2) is housed in a housing with plug terminals. 3. The voltage transformer according to claim 1 or 2, characterized in that the voltage transformer is used in a gas-insulated medium voltage circuit breaker.