MXPA06007705A

MXPA06007705A - Spark gap comprising an optically triggered power semiconductor component

Info

Publication number: MXPA06007705A
Application number: MXPA/A/2006/007705A
Authority: MX
Inventors: Menke Peter; Breuer Wilfried
Original assignee: Siemens Ag
Priority date: 2004-01-13
Filing date: 2006-07-05
Publication date: 2006-12-13

Abstract

Disclosed is a surge protector (1) comprising a spark gap (2) that is provided with two opposite electrodes (3), a circuit (5) for triggering the spark gap (2), and a light source connected to a protective device (13) on ground potential in order to generate a triggering light which can be delivered with the aid of at least one optical waveguide (15) of a receiver unit of the triggering circuit (5), the spark gap (2) and the triggering circuit (5) being on a high voltage potential. In order to make said surge protector (1) reliable and inexpensive, the receiver unit is provided with at least one power semiconductor component (16) that can be moved, with the aid of the triggering light, from a locked position in which current conduction via the power semiconductor component (16) is interrupted into an open position in which current conduction via the power semiconductor component (16) is made possible.

Description

SPARK DOWNLOADER WITH SEMICONDUCTOR COMPONENT OF POWER ON OPTICALLY Field of the Invention The invention relates to an overvoltage protector with a spark gap that presents electrodes facing each other, an ignition circuit to ignite the spark arrester and a light source at the ground potential connected to an apparatus of protection for generating an ignition light that can be fed to a receiving unit of the ignition circuit by at least one fiber optic conductor in which the spark gap and the ignition circuit are at a high voltage potential.

BACKGROUND OF THE INVENTION A protector against overvoltage of this type is already known according to the state of the art. Figure 1 shows an overvoltage protector of this type having a main spark gap 2 with main electrodes 3. The main electrodes are connected in parallel to series capacitors that are connected to an alternating voltage network of three-phase current at a high voltage potential. Through the bridging via the spark gap, the capacitor is protected against too high voltages. The series capacitors or other electronic components to be protected are arranged in a platform 4 installed in an isolated manner supported by support supports in the form of a column, not shown graphically, in an environment that is at ground potential. In this way, the main electrode 3 drawn in the lower part of FIG. 1 is, for example, at a high voltage potential corresponding to that of platform 4, while the main electrode 3 drawn on the upper part of FIG. Figure 1 is located at the high voltage potential of the three-phase network. A voltage between approximately 60 kV and 160 kV falls between the main electrodes, so that the components arranged on the platform 4 are designed for this voltage drop.

Brief Description of the Figures Figure 1 shows an overvoltage protector previously known according to the state of the art, Figure 2 shows an exemplary embodiment of the overvoltage protector according to the invention in schematic representation, and Figure 3 shows an additional embodiment of the protector against overvoltage according to the invention in schematic representation.

Detailed Description of the Invention To activate the spark arrester 2 in an active manner, an ignition circuit 5 is provided as well as an ignition electrode 6, the ignition circuit 5 having a capacitive voltage divider with a first capacitor 7 and a second capacitor 8. The second capacitor 8 can be bridged by a parallel branch in which an activation spark arrester 9 and an ohmic resistor 10 connected in series to it is arranged. The activation spark gap 9 can be bridged by an electronic control system 11 in its transmission position, in which a flow of current through the parallel branch and, therefore, a bypass of the second capacitor 8 is made possible. of the bypass, the ignition electrode 6 is located at the potential of the lower main electrode 3, which, however, is arranged spatially closer to the upper main electrode 3 than the lower main electrode 3. A spark discharge is generated which jumps to the lower main electrode 3. The electronic control system 11 can be powered by the energy needed to activate the activation spark gap 9 via a power supply 12. The ignition of the trigger spark gap 9 is activated actively. In this case, a protection device 13 controls the electrical measuring variables of the three-phase current network as well as the alternating current of each phase of the three-phase current network and / or the voltage that falls on the electronic components in the platform. If activation conditions are presented as, for example, exceeding a threshold voltage in the component, the protection apparatus 13 generates an activation signal that is transmitted to a semiconductor laser that at that moment generates an optical activation signal that is fed to the electronic control system 11 as receiving unit through a fiber optic conductor 15. Upon receiving an optical activation signal, or in other words an ignition light, the electronic control system causes an electrical activation of the spark arrester 2. The protection apparatus 13, as well as the semiconductor laser 14, are at a ground potential, so that their access and maintenance are simplified if necessary. By means of the optical fiber conductor 15, a safe conduction of the ignition light is made possible and at the same time the isolation between the platform 4 which is at the high voltage potential and the components 13 and 14 of the protector 1 against the overvoltage is conserved. that are on the ground potential. Especially, due to the necessary electronic system with power supply in platform 4, the previously known overvoltage protector requires many costs and effort in its maintenance. The object of the invention is to provide an overvoltage protector of the type mentioned at the beginning that is reliable and economical. The invention solves this objective because the reception unit has at least one power semiconductor element which, by means of the ignition light, can pass from a blocking position in which a current flow is interrupted by the power semiconductor component, a transmission position in which a current flow is enabled by the power semiconductor component. According to the present invention, the activation of the overvoltage protector is simplified. Instead of supplying the ignition light to an optoelectric transducer, for example a diode, which, depending on the received light intensity, generates an electrical activation signal, the ignition light is fed directly to a power semiconductor component that can Optically ignited, which allows a current flow through the ignition. In this way, a current flow is possible, for example, in a current branch for a short period of time, which can be used in any connection for turning on the spark gap. In contrast to the state of the art, the power semiconductor components do not require any power supply to a maintenance-sensitive high voltage potential so that the overvoltage protector according to the invention stands out with respect to its costs and reliability. Advantageously, the semiconductor components are configured as thyristors that can be switched on optically and connected in the opposite direction. The thyristors can pass actively only from their blocking position to the transmission position. The reverse process is done passively. At a current zero point of an alternating current flowing through the thyristor, the alternating current is below the holding current of the current-breaking component so that it passes back to its blocking position. To increase the resistance to voltage, several thyristors can be connected in series.

According to a convenient variant in this regard, additional optical fiber conductors are provided so that each thyristor can be supplied with an ignition light by its own fiber optic conductor. For the supply of the ignition light to the additional fiber optic conductors, for example, a corresponding number of additional light sources are provided which are connected in each case to an associated fiber optic conductor. In a different way, it is possible to use one or more optical couplers to distribute the ignition light from a single light source according to the demand to the existing fiber optic conductors. The optical couplers are known according to the state of the art so that at this point it is not necessary to go into their operation. Advantageously, the ignition circuit has a capacitive voltage divider having a capacitor that can be bridged by the power semiconductor element. By bridging one of the capacitors of the voltage divider, for example, a current shock can be generated in such a way that a voltage impulse can be generated in a ignition coil by a coil which causes the spark arrester to be activated.

Unlike this, the ignition circuit is connected to an ignition electrode whose spacing from a first electrode of the spark gap is smaller than the spacing between a first electrode and the second facing electrode, and the ignition electrode can requested by the ignition circuit with the electrical potential of the second electrode. In an advantageous variant, the spark gap has at least two pairs of electrodes facing each other which are arranged in series with respect to one another, the capacitor which can be bridged parallel to a pair of electrodes facing each other being connected. In other words, the spark gap is composed of two or more partial spark gap. After bridging the capacitor, the previously falling voltage in all partial spark arresters now falls on the partial spark arresters that are not bridged. Due to the increase in voltage drop for this reason in the unbridged part spark arresters, sparks are discharged in these partial spark arresters. After the transition of the semiconductor component to its blocking position, an increased voltage also falls on the partial spark arrester (s) connected parallel to the capacitor, which also causes a spark discharge in this case. In the context of the invention it is also possible to ignite an auxiliary spark gap by means of the power semiconductor component, which is part of the ignition circuit, in which the spark gap is ignited by turning on the auxiliary spark gap which is connected in parallel to the component to be protected. If necessary, the ignition circuit comprises several auxiliary spark arresters which are connected in series with each other to increase the resistance to the ignition circuit voltage. In this case, it may be sufficient, as already described, to bridge only an auxiliary spark gap by means of the power semiconductor components. According to a preferred variant of the invention, the spark arrester and the ignition circuit are arranged on a platform supported in isolation by supports that is configured to carry components that are intended to improve the transmission of power in a power distribution network which conducts alternating voltage. These components are, for example, capacitors or coils which serve to compensate reactive power and are connected either in series or in parallel in the three-phase current network. In this way, too large spacings can be avoided between the terminals of the components that are at a high voltage potential and the terminals at a ground potential. By connecting in parallel with the overvoltage protector, the components can be protected against overvoltage. According to the invention, the light source is, for example, a convenient laser. The laser can be in immediate proximity to the control unit and sends laser pulses to the platform to activate the overvoltage protector through the non-conductive optical fiber conductor and there they are received by the power semiconductor component with which it is provided an ignition of the spark gap and therefore the protection of the desired component on the platform. As a laser, for example, a semiconductor laser whose laser pulse can be coupled by means of a coupling element in the optical fiber conductor (s) is suitable. In a different way to this, it is possible, however, that a fiber laser that is pumped by means of a semiconductor laser is integrated in the fiber optic conductor (s). In this case, the semiconductor laser is connected to a protection device which is again supplied with electrical quantities by transducers measuring, for example, the voltage that falls on a component for which protection is provided against overvoltage. The component is, for example, a capacitor arranged on a platform that is connected in series to a phase of a three-phase current network. The measurement values generated by the transducer are recorded and digitized and the protection apparatus compares the digital voltage values derived from the measurement values with the activation conditions by means of a logical system implemented therein and when a condition of Activation generates an activation signal that causes the semiconductor laser to send a laser pulse. Other suitable variants and advantages of the invention are the object of the following description of embodiments of the invention with reference to the figures of the drawing, in which, figure 1 shows a protector against overvoltage previously known according to the state of the art , figure 2 shows an example of embodiment of the overvoltage protector according to the invention in schematic representation, and figure 3 shows a further embodiment of the overvoltage protector according to the invention in schematic representation.

Figure 1 shows a protector against overvoltage according to the state of the art that was already described above. FIG. 2 shows an exemplary embodiment of the overvoltage protector 1 according to the invention which is intended to protect a component not shown graphically, such as, for example, a high-voltage capacitor in which the high-voltage capacitor is connected in series to a network of three-phase high-voltage current. As already described in relation to FIG. 1, the electrical components arranged on the platform 4 are at a high voltage potential whose voltage drop is in the medium voltage range with respect to the corresponding phases of the power supply network. triphasic current. In this way too large spacings are avoided to cause the necessary tensile strengths. The overvoltage protector is arranged connected in parallel with respect to the component to be protected. In the same way as the overvoltage protector according to FIG. 1, the overvoltage protector 1 according to FIG. 2 is activated in an active manner, feeding voltage values that fall on the component to be protected to the protection apparatus 13 check these values when an activation condition occurs. If the voltage falling on the component to be protected exceeds, for example, a maximum threshold value, the protection apparatus generates an electrical activation pulse to activate the laser 14, which at that moment generates a light pulse as light ignition that can be coupled to the fiber optic conductor 15. The non-electrically conductive optical fiber conductor 15 is connected at its opposite end to the laser 14 to a thyristor 16 which, after receiving an ignition pulse via the fiber optic conductor 15, passes from a blocking position, in which it is interrupted a current flow through the thyristor 16, to its transmission position in which a current flow in one direction is possible. The overvoltage protector 1 shown is provided for alternating currents so that to facilitate a transmission of different pole currents two thyristors are connected to one another in parallel in the opposite direction. Also the second thyristor 16 is coupled to a fiber optic conductor 15 which is directed towards the laser. In this case, the laser 14 is equipped with means which, according to the control signal on the side of the protection apparatus 13, couple the ignition light in one or other of the fiber optic conductors 15.

If one of the thyristors 16 is in its transmission position, the ignition electrode 6, whose spacing from the upper main electrode 3 in FIG. 2 is smaller than the separation of the lower main electrode 3 from the upper main electrode, it is connected to the potential of the lower main electrode. Due to the decrease in the separation a disruptive discharge is reached between the upper main electrode 3 and the ignition electrode 6 and the ignition spark jumps from the upper main electrode to the lower main electrode as soon as the two thyristors 16 meet again in its blocking position. This occurs at a zero point of the alternating current. 3 shows a further exemplary embodiment of the overvoltage protector 1 according to the invention in schematic representation. The spark arrester 2 is composed here of two partial spark arresters 17 which in each case have a pair of electrodes 3 facing one another. The partial spark arresters 17 are arranged connected in series and are connected in each case parallel to a capacitor 7, 8. With the bridging of the capacitor 8 by turning on the thyristors 16, the total voltage drops in the partial spark gap 17 upper of figure 3 whose electrodes have an insufficient separation to maintain the total tension. An ignition spark originates. After passing thyristors 16 to their blocking position, the total tension drops in the partial spark arrester 17 drawn in the lower part in figure 3, which at that moment also ignites. Each of the partial spark arresters has a gas-tight casing 18. By means of the series connection of partial spark arresters 17 the spark arrester 2 can be designed together for higher voltages without having to be disadvantaged with respect to its control possibilities. In this way the spark arrester shown in Figure 3 is designed for voltages in the range between 160 kV and 300 kv. On the other hand, the overvoltage protector shown in FIG. 2 can be used advantageously for voltages in the range between 60 kV and 160 kV.

Claims

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following is claimed as property:

CLAIMS: 1.- Protector (1) against overvoltage with a spark arrester (2) that has electrodes (3) facing each other, a circuit (5) to ignite the spark arrester (2) b and a source (14) of light to the ground potential connected to a protection apparatus (13) to generate an ignition light that can be fed to a receiving unit of the ignition circuit by means of at least one fiber optic conductor (15), in that the spark gap (2) and the ignition circuit (5) are at a high voltage potential, characterized in that the receiving unit has at least one power semiconductor component (16) which, by means of the ignition light , it can pass from a blocking position, in which a current flow is interrupted by the power semiconductor component (16), to a transmission position in which a current flow is enabled by the semiconductor component (16) of po tencia
2. - Protector (l) against overvoltage according to claim 1, characterized in that the power semiconductor components are realized as thyristors (16) that can be turned on optically and are connected in opposite directions.
3. Protector (1) against overvoltage according to claim 1 or 2, characterized in that the ignition circuit (5) has a capacitive voltage divider (7, 8) that has a capacitor (8) that can be bridged by the component (16) power semiconductor.
4. Protector (1) against overvoltage according to one of the preceding claims, characterized in that the ignition circuit (5) is connected to an ignition electrode (6) whose separation with respect to a first electrode (3) of the arrester ( 2) is less than the separation between the first electrode (3) and a second electrode (3) facing it, in which the ignition electrode (6) can be requested by the ignition circuit (5) with the potential of the second electrode (3).
5. Protector (1) against overvoltage according to one of claims 1 to 3, characterized in that the spark gap (2) has at least two pairs of electrodes (3) facing each other that are arranged connected in series with each other , in which the capacitor (8) that can be bridged is connected in parallel to a pair of the electrodes (3) facing each other.
6. Protector (1) against overvoltage according to one of the preceding claims, characterized in that the spark gap (2) and the ignition circuit (5) are arranged on a platform (4) supported in an isolated manner by supports that are configured to carry components that are intended to improve power transmission of an energy distribution network.