Arrangement of RC elements designed for medium voltage for switching small induced currents at high voltage levels using vacuum switching techniques

Abstract

The invention provides an RC (Resistance-Capacitance) element circuit device designed for medium voltage. And the RC filter circuit adopts a high-voltage vacuum switch technology to switch small induction current within a high-voltage range of 72.5 kV. Advantageous further designs relate to specific arrangements for limited installation spaces in substations.

Description

Technical Field

[0001] The present invention relates to an arrangement of RC elements designed for medium voltage, used to realize an RC filter circuit solution for switching small inductive currents using high voltage vacuum switch technology. Background Art

[0002] When switching small inductive currents, such as occur in high-voltage networks (>=72.5 kV) in choke applications, special protective measures are required. Switching tasks carry the risk that transient overvoltages may damage substation components. The choke itself is particularly at risk here. Switching media are, for example, gas switches and vacuum switching devices.

[0003] In high-voltage power grids, SF6 power switches are mainly used. In these applications, gas switches cannot be operated without additional protective measures. These measures are used to reduce the overvoltages that occur during the switching process.

[0004] Until now, applications for choke switches in high-voltage grids (>=72.5 kV) have been served by a combination of an electronic controller (controlling the exact time of switching on or off) and an SF6 power switch with unipolar drive. This solution is costly, requires more effort during commissioning, and carries the risk that the data of the power switch stored in the controller (e.g. the intrinsic time of the switch) will change during operation - over decades. This could change the optimal switching time and impair the functionality of the arrangement consisting of a unipolar driven power switch and an electronic controller. Summary of the invention

[0005] The problem to be solved by the present invention is to propose a solution for using RC filter circuits in high voltage power transmission, wherein the high voltage (HV) is greater than or equal to 72.5 kV. In addition, the present invention aims to propose a variant for the arrangement of RC elements so that they can be effectively integrated into the limited installation space in the substation architecture.

[0006] This problem is solved by a circuit arrangement comprising a plurality of RC elements according to the features of claim 1 .

[0007] The effects of transient overvoltages can be significantly reduced by using an RC filter circuit (a series circuit of a resistor R and a capacitor C). This solution has been used for many years in medium voltage and is state of the art. Therefore, the RC filter circuit assembly can also be used at medium voltage levels.

[0008] The transfer of this technology to high voltage applications also opens the way for the application of choke switches in high voltage vacuum switchgear. The arrangement according to the invention of the available discrete medium voltage outdoor RC elements is an efficient method that can also be used for high voltage applications. The efficient arrangement of these RC elements may be particularly suitable for integration into the corresponding substation architecture. The available installation space is tight here.

[0009] Existing medium voltage RC solutions basically cover the voltage range up to 36kV. In order to be able to expand to high voltage, according to the present invention, several of these elements are interconnected with each other. The R element and the C element can be installed together in a metal housing G. The housing has a bushing D that is resistant to outdoor use. The electrical series connection of such discrete components makes it possible to use at higher voltage levels.

[0010] In an advantageous further development of the invention, the RC element is fixed by a supporting insulator or a plurality of supporting insulators SI. This serves on the one hand to ensure mechanical strength and on the other hand to maintain a distance intended for voltage isolation.

[0011] Advantageous further developments of the invention are specified in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The invention is explained in more detail below using an exemplary embodiment with the aid of the drawings to the extent necessary for an understanding.

[0013] Figure 1 An arrangement according to the invention of three separate RC elements is shown, wherein the bushings are oriented towards the same side;

[0014] Figure 2 An arrangement according to the invention of three separate RC elements is shown, with the bushings facing opposite sides;

[0015] Figure 3 shows an arrangement according to the invention of three separate RC elements, wherein the bushings are arranged in a row; and

[0016] Figure 4 An arrangement according to the invention of three individual RC elements is shown in precisely two planes.

[0017] In these drawings, like reference numerals denote like elements. DETAILED DESCRIPTION

[0018] Figure 1An arrangement according to the invention of individual RC elements is shown. The main surfaces of three RC elements RC are arranged parallel to one another, each of which has a series circuit consisting of a resistor and a capacitor. Each of these RC elements is designed for medium voltages up to 36 kV. Each of these RC elements has two electrical connections, namely a housing connection GA and a bushing connection DA. The bushing connection DA is arranged at the end of the bushing D facing away from the housing G. The bushing D itself can be arranged on the housing G, offset from the center of its fastening surface.

[0019] In accordance with Figure 1 In the arrangement, the bushing joints DA of several RC elements face one side. The bushing joints DA of adjacent RC elements can be arranged staggered with respect to each other, in particular to the right or to the left, in order to improve the interconnection of the RC elements. The RC elements can be arranged stacked one above the other or also arranged horizontally side by side. This allows adaptation to the corresponding spatial conditions in the substation. The RC elements can be fixed by support insulators, not shown in the figure. The support insulators serve on the one hand to ensure mechanical strength and on the other hand to maintain distances intended for voltage insulation.

[0020] Figure 2 A second possible arrangement of the individual RC elements is shown, wherein the bushings D of the separate RC elements are arranged alternately on the front side and the rear side. To improve the interconnection of the individual RC elements, the bushings are arranged alternately on the left and the right side. The RC elements can be arranged stacked one above the other or also arranged horizontally side by side. This allows adaptation to the respective spatial conditions in the substation. The RC elements can be fixed by support insulators, not shown in the figure. The support insulators serve on the one hand to ensure mechanical strength and on the other hand to maintain distances intended for voltage insulation.

[0021] Figure 3 An arrangement is shown in which the RC elements are arranged vertically one above the other, but their bushings D are also arranged in a row. There are two possibilities here: As shown in the left figure, the bushings D are arranged alternately left and right. On the other side of the RC element, a supporting insulator SI is arranged accordingly, which absorbs the forces of the stacked elements. The housing G of the lowest RC element is directly connected to the base surface with ground potential. This arrangement only requires two supporting insulators SI for three RC elements.

[0022] However, there is also a solution, such as Figure 3 As shown on the right, all bushings D are arranged on one side and all supporting insulators SI are arranged on the other side. The lowest RC element is directly connected to the base surface with ground potential via the bushing connection DA of its bushing D. This arrangement requires three supporting insulators SI for three RC elements.

[0023] Figure 4A particularly compact arrangement of RC elements is shown. The elements are here situated next to each other exactly in two planes. They are arranged vertically and interconnected from the element on the left to the element on the right. Here too, the bushings can always be arranged on one side (as shown) or also alternately (front side / rear side). The housing G of the lowest RC element is connected directly to the base surface with ground potential.

[0024] The series connection of the RC elements can be further designed such that a high-ohmic resistor with the same resistance value is connected in parallel to each RC element. This ensures that the high voltage HV is evenly distributed to the individual RC elements.

[0025] The RC element may be of the commercial MV APP type available from TDK Electronics AG.

[0026] High voltage in the sense of the present invention refers to voltage of 72.5 kV (kilovolts) and above, including direct current voltage, alternating current voltage, and if it is three-pole, it also includes three-phase electricity.

[0027] The present invention has been described in detail with reference to specific embodiments for illustrative purposes. Here, the elements of the various embodiments may also be combined with each other. Therefore, the present invention should not be limited to the individual embodiments, but should only be limited by the attached claims.

[0028] List of Reference Numerals

[0029] D-Bushing / Leader / Voltage Bushing

[0030] DA-Casing Connector

[0031] EP-ground potential, grounding

[0032] G-housing

[0033] HV-high voltage, high voltage

[0034] SI - Support Insulator.

Claims

1. A circuit arrangement in high-voltage electrical energy transmission, provided with an electrical RC element designed for medium voltage, wherein: The high voltage (HV) is greater than or equal to 72.5 kV, It is characterized in that A series circuit including a plurality of RC elements is arranged between the conductor carrying the high voltage (HV) and the ground potential (EP), and A sum of the withstand voltages of the plurality of RC elements is greater than the high voltage (HV).

2. The circuit arrangement according to claim 1, It is characterized in that Each RC element has a cuboidal, in particular metallic, housing (G). A voltage bushing (D) resistant to outdoor use is provided on one side of the housing. A first connection (GA) is provided on the housing, and a second bushing connection (DA) is provided via the voltage bushing (D). A series circuit consisting of at least one resistor and at least one capacitor is arranged in the housing and is connected to the first connection (GA) or the second bushing connection (DA).

3. The circuit arrangement according to claim 2, It is characterized in that The voltage bushing (D) is arranged eccentrically on the end face of the housing.

4. The circuit arrangement according to claim 2 , It is characterized in that The main surfaces of the RC elements face each other, and their voltage bushings (D) are arranged alternately offset from each other on one side of the housing.

5. The circuit arrangement according to claim 2 , It is characterized in that The main surfaces of the RC elements face each other, and their voltage bushings (D) are arranged alternately on opposite sides of the housing.

6. The circuit arrangement according to claim 2 , It is characterized in that The RC element is connected in series to the voltage bushing (D) of the adjacent RC element.

7. The circuit arrangement according to any one of the preceding claims 2 to 5, It is characterized in that The main surfaces of the RC elements are arranged on exactly two different planes, and the RC elements in different planes are electrically connected one after the other.

8. The circuit arrangement according to claim 1, characterized in that The RC elements are fixed by support insulators (SI).

9. The circuit arrangement according to claim 1, characterized in that Each RC element has a high-ohmic resistor of the same resistance value connected in parallel.

10. The circuit arrangement as claimed in claim 1, characterized in that The circuit arrangement is interconnected with a high-voltage vacuum switchgear which switches the choke.

Images