DE3110119A1 - Indicator of the direction of power flow - Google Patents

Abstract

When short circuits occur in the operation of electricity supply systems (predominantly medium-voltage systems in this case), it is attempted to find the source of the fault as quickly as possible. To find the fault quickly, short-circuit indicators are used. The short-circuit indicators hitherto used in practice could only be used in radial systems with one feed point. The indicator of the direction of power flow is capable of finding and indicating the power flow in a power system. This makes it possible to monitor ring systems and parallel systems having one or more feed points. The operation of the indicator of the direction of power flow is determined by the phase angle of the alternating voltage from a generator (Figure 1) being picked up and stored for a short period in the case of a short circuit (the alternating voltage drops to zero volts). Thus, the phase angle of the alternating voltage can be compared with the phase angle of the alternating current at the instant of the short circuit. The displacement in the phase angle between alternating current and alternating voltage allows the direction of power flow to be determined. <IMAGE>

Description

Electronic energy direction indicator

Energy direction indicators show that an electrical overload has occurred Lines on.

They are used to monitor cable and rail systems (Ring network line with two or more feeds or parallel network lines fed on one side).

The energy direction indicator is installed in electrical lines (low, Medium and high voltage systems) are used. It shows the exceeding of a predetermined one overload limit and in which direction the energy flowed. The cause the overload is between the energy direction indicators facing each other to find.

Using this device, a safe and fast overload location is achieved in ring and parallel networks.

Energy direction indicators are known (Licentia Patent-Verwaltungs-GmbH, 6000 Frankfurt, Auslegeschrift No. 24 12 792.) The mentioned direction indicator must be supplied separately with an externally supplied mains voltage. This supply voltage must not be derived from the high-voltage network to be monitored, as in the event of a short circuit the phase comparison between current and voltage due to the loss of voltage does not can be carried out. The insulation properties of the required current transformer must meet the test conditions of a high-voltage network. this device is in today's high-voltage networks only under special conditions or under can be used at high cost.

The invention is based on the object of offering a device which works safely under all conditions and can be offered for a cheap price.

The task is solved by the fact that the frequency of the high voltage is passed on to a generator via a SungsfUh1er (capacitive probe), which records the frequency and the phase position synchronously and when the mains voltage fails stores this for a certain time (flywheel generator) and sends it to the phase-detecting Circuit forwards. The phase position of the current required for comparison is tapped inductively via a coil.

To avoid false displays (e.g. brief inrush current van transformers) an electronic interference suppression is built in, the only after 2 - 3 full waves does the triggering impulse pass on to the phase-identifying one Circuit. The evaluation is carried out. The result is in a bistable multivibrator held and according to the direction of flow of energy in the high-voltage network forwarded to one of the two display systems. The provision (on standby) takes place automatically when the high-voltage network is switched on again or after one fixed time.

The "energy direction indicator" shown here is directly on the Services of the high-voltage network put on. He doesn't need anyone from outside Power supply and can therefore be used at any point in the high-voltage network will. Problems regarding compliance with the regulations in high-voltage systems do not arise. The device can be manufactured much more cheaply than previously known devices.

The energy direction indicator shows when a specified energy flow load limit is exceeded. Fig. 1. A special case of overload is the short circuit, for this purpose a special device was developed. Embodiments are in the enclosed Circuit diagrams shown and described in more detail below.

Fig. 1 To determine the direction of energy flow, it is necessary that the voltage is taken from the high-voltage network via a sensor F 1. the Pulses are passed on to a flywheel generator N2 / N3. The beach will picked up via a coil and amplified with transistor T 1, passed on via the gate N 5 / N 8 The threshold of tranzistor T 1 is determined by resistance R 5 adjusted.

After the response threshold is exceeded, the first impulses suppressed by the counting flip-flop N 22. At the same time, these impulses synchronize the flywheel generator.

After the delay time has elapsed, gate N 10 is enabled.

The next current pulse starts the flip-flop N 20, which takes 5ms gives an enable signal to the memory stage N 21. Here is the phase comparison between current and voltage, which is carried out by gate N 4, is stored.

The counter N 24 is reset with the same current pulse, as well the tilting stage N 23. This enables the clock generator N 15 / N 16, which over the gates N 17 or N 18, linked with the stored Susgangssignalen on N 21, either transistor T 2 or T 3, which controls the associated display elements Display LA 1 or IA 2 flashing. At the same time the output of blocks N 13 the gate N 5, so that no further Stranippulse become effective.

The flashing pulses are added up in counter N 24 at the same time. Corresponding The output of the counter blocks the specified number of pulses (running time approx. 1-4 hours) N 24 the clock generator N 15 / N 16.

A second way of resetting is via the retriggerable monostable multivibrator N 19. After a brief interruption of the high voltage (KU circuit) gives the flip-flop N 19 a setting pulse to the bistable flip-flop N 23, which is independent of counter N 24 stops the clock generator N 15 / N 16.

By stopping the clock generator N 15 / N 16, the energy direction indicator is ready for action again.

Fig. 2 The impulses are recorded and processed as in Fig. 1, the current pulse allowed to persist by gate N 10, the trigger stage N 26 starts, the output pulse of which releases the storage stage N 25 after 5 ms causes.

Here the phase comparison between current and voltage, which is made by Gate N 4 is carried out, stored. The output pulse of flip-flop N. 26 stimulates the flip-flop N 27 to an output signal of approx. 30 ms. This signal controls via gates N 30 and N 31 in conjunction with the stored output signals from N 25 the transistors T 4 or T 5 on.

The response coils of the bistables are set according to the specified time Display systems A 1 or B 1 excited.

With the current pulse coming from gate N 10, the counter N 29 reset. This enables the clock generator N 33. At the same time will Gate N 5 blocked for further current pulses.

The clock pulses are added up in the counter N 29. Corresponding The output of the counter blocks the specified number of pulses (running time 1-4 hours) N 29 the clock generator N 33. This enables the gate N 5. Simultaneously the trigger stage N 28 is triggered and gives an output for 30 ms signal to the transistors T 6 and T 7 the associated reset coils A 2 and B 2 of the bistable display systems.

A second way to reset is via the retriggerable one monotable multivibrator N 19.

When the high-voltage network is switched on again, the flip-flop is active N 19 sends a pulse to the monostable multivibrator N 28, which controls the reset systems via T 6 and T 7 A 2 and B 2 actuated.

L e r s e i t e

Claims (10)

Patent claims 1. Direction indicator for displaying the flow of energy in alternating current ring networks and alternating current parallel connections using the phase shift between alternating voltage and alternating current and d alternating current shifted by 180 °, g e k e n n n z e i c h n e t d a d u r c h that the phase position of the alternating voltage is passed on to a synchronously rotating flywheel generator N 2 / N 3, which e.g. forms unique square wave signals and these after the high voltage has ceased for saves a certain time and is available to the phase-detecting circuit represents. 2. Direction indicator according to claim 1, since d u r c h gek e n n -z e i c h n e t that in the event of a short circuit, as a special case of overload, the indicator as Kunzschlussanzeiger works. 3. Direction indicator according to claim 1 and 2 g e k e n n z e i c h n e t d a d u r c h that the phase position of the current, which the given response value exceeds, is recorded via the sensor L 1 and synchronized with the flywheel generator (N 7 / N 8) is passed on. This generates, for example, square-wave signals that are sent to the phase-detecting Circuit are forwarded. 4. Direction indicator according to claim 1 and 2, d a d u r c h g e k e n n -z e i c h n e t that the detection of the phase position of the current via magnetic field direction-dependent Elements (e.g. coil, Halgenerator) is recorded. 5. Direction indicator according to claim 1 and 2, d a d u r c h g e k e n n -z e i c h n e t that the phase position of the current is synchronized with a generator is transmitted. 6. Direction indicator according to claim 1 and 2, d a d u r c h g e k e n n -z e i c h n e t that short-term current pulses are suppressed by initially some wellas do not reach the evaluation. 7. Direction indicator according to claim 1 and 2, d a d u r c h g e k e n n -z e i c h n e t that the display takes place: via light-emitting diode or fluoriziernede Elements or liquid crystal displays or glow lamps or mechanical bistable Display elements that are each controlled by transistor or thyristor or the output of an integrated circuit. 8. Direction indicator according to claim 1, 2 and 7, g e k e n n z e i c h n e t d a d u r c h that for remote reporting and further evaluation in the display, Purpose decoupling from the high voltage area, a fiber optic system is used will. This system can be used to forward the ad and reverse it Resetting the direction indicator can be used in readiness. 9. Direction indicator according to claim 1 and 2, d a d u r c h g e k e Note that the power supply is provided by primary batteries (e.g. lithium cell, Alkaline manganese cell, air oxygen cell) or rechargeable batteries in Connection to an integrated charging device takes place. 10. Direction indicator according to claim 1 and 2, g e k e n n z e i c h n e t d a d u r c h that the provision is achieved in standby mode: 1) inden the recorded via the sensor after switching on the high-voltage network again Impulse is processed, a trigger stage is excited and thus the electronics are ready brings, 2) by charging a capacitor from the discharge current of the sensor and the electronics via a switching element (e.g. trigger diode, discharge path) gets ready.