DE29617365U1 - Circuit arrangement for the energy supply of electronic tripping devices - Google Patents

Description

Circuit arrangement for supplying power to electronic tripping devices
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The invention relates to a circuit arrangement for supplying power to electronic tripping devices with a current transformer device, the output voltage of which is rectified and can be fed to a charging capacitor which supplies power to the electronic tripping device. The circuit arrangement defined at the beginning is known from DE 32 46 329 A1. Such circuit arrangements have the property that, when there are high primary currents in the network, the secondary sides of the current transformer devices are generally not short-circuit-proof. This property is all the more pronounced the less complex the current transformer devices are. The secondary windings of the current transformer devices have a small winding cross-section, not least for cost reasons. When the secondary sides are subjected to greater loads, voltage peaks of several hundred volts also occur, so that the electronic power supply circuits must be dimensioned accordingly.
In the known circuit arrangements, the secondary current of the current transformer device is fed to the charging capacitor via a controlled switching device, for example via an electronic switch. As soon as the charging capacitor has reached a sufficiently high charging voltage, the electronic switch interrupts the flow of current. In order to reduce the very high output voltage that then occurs at the current transformer device to tolerable voltage values,

GR 96 G 4171 DE

To limit this, components with high power losses are used, which are correspondingly expensive. In addition, significant problems arise with the proper dissipation of the resulting power losses.

The object underlying the invention is to provide a circuit arrangement for supplying energy to electronic triggering devices that generates practically no power loss. According to the invention, this is achieved by the features

1.1 the current transformer device contains an energy converter,

1.2 the voltage of the energy converter is fed directly to the charging capacitor,

1.3 the charging capacitor is connected in parallel to the input of a switching power supply,

1.4 the switching power supply generates an auxiliary voltage on the output side,

1.5 the auxiliary voltage is supplied to the electronic tripping device for energy supply.

The auxiliary voltage required for the triggering device is therefore generated by the switching power supply. The voltage supply for the switching network, which is in the range of 10-300 volts, is provided directly by the voltage of the energy converter, whose current charges the charging capacitor. In connection with a three-phase network, it is also conceivable that other phases also feed their current into the charging capacitor via appropriate decoupling by rectifiers.

By using the switching power supply, practically no power loss is produced. In addition, the energy

GR 96 G 4171 DE

gy converters also do not have any voltage peaks caused by power interruptions. The components are therefore not designed for peak load cases and are therefore cheaper.

According to an advantageous development of the invention, the features

2.1 the current transformer device contains a measuring transformer,

2.2 The voltage of the measuring converter can be fed directly to the electronic tripping device, so that the current measurement for controlling the tripping devices is carried out independently of the auxiliary voltage.

The invention is explained in more detail by an embodiment in which only the switching devices essential for understanding the invention are shown as functional blocks.

The circuit arrangement for supplying energy to the electronic tripping devices contains a current transformer device, which is made up of the energy converter (EW) and the measuring converter (MW). The energy converter (EW) is connected to the rectifier device (GE), which rectifies the current of the energy converter (EW) and charges the charging capacitor (CL) with the appropriate voltage. The switching power supply (SN) with its input lines is arranged in parallel to the charging capacitor (CL). A constant auxiliary voltage (UH) is generated on the output lines of the switching power supply (SN), which serves to supply energy to the tripping device (AE).

96 G 4171 en :··. .·:.:..:

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The measuring transducer (MW) measures the current in the network and, in a manner not shown, activates the tripping device (AE).

Claims (2)

GR 96 G 4171 DE ···* "2··..· Protection claims 1. Circuit arrangement for supplying energy to electronic tripping devices with a current transformer device whose output voltage is rectified and can be fed to a charging capacitor which provides energy to the electronic tripping device, characterized by the features 1.1 the current transformer device contains an energy converter (EW), 1.2 the voltage of the energy converter (EW) is fed directly to the charging capacitor (CL), 1.3 the charging capacitor (CL) is connected in parallel to the input of a switching power supply (SN), 1.4 the switching power supply (SN) generates an auxiliary voltage (UH) on the output side, 1.5 The auxiliary voltage (UH) is supplied to the electronic release device (AE) for energy supply. 2. Circuit arrangement for supplying energy to electronic triggering devices according to claim 1, characterized by the features 2.1 the current transformer device contains a MeS converter (MW), 2.2 The voltage of the measuring transducer (MW) can be fed directly to the electronic tripping device (AE).