KINEMATIC LINKAGE ARRANGEMENT FOR A SWITCHING DEVICE

Abstract

A switching device having a pole assembly, a drive unit, and a kinematic linkage arrangement is provided. The pole assembly includes interrupter units operably connected via an interlink arrangement representing a circuit breaker and a grounding switch, respectively. The drive unit operates the interrupter units. The kinematic linkage arrangement includes at least a lever member operably connected to the interlink arrangement and the drive unit, a cam member rigidly connected to the drive unit, and an elastic member adjustably connected to the cam member. The kinematic linkage arrangement transfer a predefined torque to the drive unit to maintain the circuit breaker in an open state.

Claims

1. A switching device comprising: a pole assembly comprising: a first interrupter unit providing a path for current flow through the first interrupter in a closed state and interrupting the current flow in an open state; and a second interrupter unit operably connected to the first interrupter unit via an interlink arrangement, wherein the second interrupter unit allows the current flow through the first interrupter unit in an open state and grounds the switching device in a closed state; a drive unit configured to operate the first interrupter unit and the second interrupter unit of the pole assembly; and a kinematic linkage arrangement comprising at least a lever member, an elastic member, and a cam member, wherein the lever member is operably connected to the interlink arrangement of the pole assembly and to a drive unit shaft of the drive unit via an elongate member of the drive unit, wherein the cam member is rigidly connected to the drive unit shaft of the drive unit, and wherein the elastic member is adjustably connected to the cam member.

2. The switching device of claim 1, wherein an axial rotation of the drive shaft causes a reciprocal rotation of the elastic member along the cam member.

3. The switching device of claim 1, wherein the elastic member and the cam member are configured to provide a predetermined torque to the drive unit for maintaining the first interrupter unit in an open state.

4. The switching device of claim 2, wherein the elastic member and the cam member are configured to provide a predetermined torque to the drive unit for maintaining the first interrupter unit in an open state.

5. The switching device of claim 3, wherein the predetermined torque is a function of a time delay required to be maintained between movement of the first interrupter unit from the closed state to the open state and movement of the second interrupter unit from the open state to the closed state.

6. The switching device of claim 4, wherein the predetermined torque is a function of a time delay required to be maintained between movement of the first interrupter unit from the closed state to the open state and movement of the second interrupter unit from the open state to the closed state.

7. The switching device of claim 1, wherein the lever member is configured to pivot about a point for enabling movement of the first interrupter unit and the second interrupter unit between the closed state and the open state.

8. The switching device of claim 1, wherein the kinematic linkage arrangement is configured to assume a first position and a second position, such that when in the first position the first interrupter unit is in the closed state and the second interrupter unit is in the open state, and when in the second position, the first interrupter unit is in the open state and the second interrupter unit is in the closed state.

9. The switching device of claim 1, wherein the switching device is a medium voltage switchgear having an operational rating of up to approximately 38 kilo Volts and up to approximately 40 kilo Amperes.

10. The switching device of claim 1, wherein the switching device is a medium voltage switchgear having an operational rating of up to approximately 38 kilo Volts and up to approximately 40 kilo Amperes.

11. The switching device of claim 6, wherein the switching device is a medium voltage switchgear having an operational rating of up to approximately 38 kilo Volts and up to approximately 40 kilo Amperes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1A illustrates a wind power generation system according to the state of the art.

[0014] FIG. 1B illustrates a wind power generation system including a switching device having a combined functionality of circuit breaking and ground switching, according to the state of the art.

[0015] FIG. 2 illustrates a three-phase medium voltage switchgear according to an embodiment.

[0016] FIG. 3 illustrates a kinematic linkage arrangement of a pole assembly shown in FIG. 2, according to an embodiment.

[0017] FIG. 4A illustrates the pole assembly of the switchgear shown in FIG. 2.

[0018] FIGS. 4B-4C illustrate enlarged views of a portion of the pole assembly, marked “A” in FIG. 4A showing various positions of the kinematic linkage arrangement shown in FIG. 3.

[0019] FIG. 5 illustrates an elastic member of the kinematic linkage arrangement shown in FIG. 3, according to an embodiment.

DETAILED DESCRIPTION

[0020] Various embodiments are described with reference to the drawings, where like reference numerals are used to refer like elements throughout. In the following description, for the purpose of explanation, numerous specific details are set forth in order to provide thorough understanding of one or more embodiments. It may be evident that such embodiments may be practiced without these specific details.

[0021] FIG. 2 illustrates a three-phase medium voltage switchgear 200 according to an embodiment of the present disclosure. The switchgear 200 includes pole assemblies 201A, 201B, and 201C each connected to an electrical phase. The pole assemblies 201A-201C are connected to a common drive unit 206. Each of the pole assemblies 201A-201C include a vacuum interrupter 202 operably connected to another vacuum interrupter 203 via an interlink arrangement 204. The vacuum interrupters 202 and 203 represent the circuit breaker 101 and the grounding switch 102 shown in FIG. 1A. The drive unit 206 operates these vacuum interrupters 202 and 203. The switchgear 200 thus includes an integration of the circuit breaker and the grounding switch into a single device. The interlink arrangement 204 allows for an adjustment of a stroke of the vacuum interrupter 203 (e.g., the grounding switch) without affecting the stroke of the vacuum interrupter 202 (e.g., the circuit breaker). The switchgear 200 also includes a kinematic linkage arrangement 205 physically disposed against the drive unit 206 and operably connected to the drive unit 206.

[0022] FIG. 3 illustrates the kinematic linkage arrangement 205 of the pole assembly 201A shown in FIG. 2, according to one embodiment of the present disclosure. The kinematic linkage arrangement 205 includes a triangular shaped lever 205A operably connected to the interlink arrangement 204. The lever 205A is shaped to be pivotable about a point P when fixed to the interlink arrangement 204, allowing freedom of movement at point M1. A pivotal movement of the lever 205A about point P results in a linear movement of the lever 205A about point M1 along a groove 204A provided on an enclosure 204 housing therewithin the interlink arrangement 204. Thus, the lever 205A is in operable connection with the moveable members (not shown) of the interrupter units 202 and 203 via the groove 204A. Therefore, the linear movement of the lever member 205A results in opening and closing operations of the first interrupter unit 202 and the second interrupter unit 203.

[0023] The kinematic linkage arrangement 205 includes an elastic member 205B, a cam 205C, and a pin 205D. The pin 205D is fixedly mounted on a drive unit shaft 206A of the drive unit 206 such that rotation of the drive unit shaft 206A results in rotation of the pin 205D. The drive unit shaft 206A is operably connected to each of the pole assemblies 201A-201C, as shown in FIG. 2, via an elongate member 206B of the drive unit 206. The lever 205A is fixedly connected to the elongate member 206B at point M2. The elongate member 206B is fixedly connected to the pin 205D such that rotation of the pin 205D along with an axial rotation of the drive unit shaft 206A causes the elongate member 206B to move linearly. The cam 205C is fixedly attached to the drive unit shaft 206A such that axial rotation of the drive unit shaft 206A causes rotation of the cam 205C therewith. The elastic member 205B is adjustably attached to the cam 205C, such that with rotation of the cam 205C, the elastic member 205B glides over the cam 205C.

[0024] FIG. 4A illustrates the pole assembly 201A of the switchgear 200 shown in FIG. 2. The pole assembly 201A includes vacuum interrupters 202 and 203 connected via the interlink arrangement 204. The vacuum interrupters 202 and 203 are supported via post insulators 207 and are operated by the drive unit 206. FIGS. 4B and 4C illustrate an enlarged view of a portion of the pole assembly 201A, marked “A” in FIG. 4A, showing various positions of the kinematic linkage arrangement 205 shown in FIG. 3. As shown in FIG. 4B, the kinematic linkage arrangement 205 is in a first position FP. As shown in FIG. 4C, the kinematic linkage arrangement 205 is in a second position SP. In the first position FP, the lever 205A is in a default position, where the first interrupter unit 202 (e.g., the circuit breaker) is closed and the second interrupter unit 203 (e.g., the grounding switch) is open. In the second position SP, the lever 205A is pivoted by rotation of the drive unit shaft 206A, as disclosed in the detailed description of FIG. 3, to open the first interrupter unit 202 and close the second interrupter unit 203. The contact springs L1 and L2 wound on the moveable contact arms (not shown) of the interrupter units 202 and 203 respectively impart a closing force onto the contacts (not shown) of the interrupter units 202 and 203 in respective closed states. The elastic member 205B shown in FIG. 3 provides there is a time delay maintained after the first interrupter unit 202 opens and before the second interrupter unit 203 closes.

[0025] FIG. 5 illustrates the elastic member 205B of the kinematic linkage arrangement 205 shown in FIG. 3, according to an embodiment of the present disclosure. The elastic member 205B includes opening springs 205E wound on a kinematic linkage shaft 205F. The kinematic linkage shaft 205F is adjustably connected to the cam 205C, which is rigidly connected to the drive unit shaft 206A. The drive unit shaft 206A is rotatable to a predefined degree, about an axis X-X′ passing therethrough. The cam 205C rotates along with the drive unit shaft 206A, causing the kinematic linkage shaft 205F to slide in the direction shown by the arrows along an outer surface 205C′ of the cam 205C.

[0026] The opening springs 205E exert a torque while the drive unit shaft 206A is rotated in a clockwise direction (e.g., while opening operation of the circuit breaker, the first interrupter unit 202 shown in FIG. 2). This torque is defined based on the time delay (e.g., 12-16 milli seconds) required to be maintained before the grounding switch 203 closes post opening of the circuit breaker 202. This time delay provides complete discharge of the voltage across the contacts of the circuit breaker 202 before the switchgear 200 is grounded by closing of the grounding switch 203.

[0027] While the present invention has been described in detail with reference to certain embodiments, it should be appreciated that the present invention is not limited to these embodiments. In view of the present disclosure, many modifications and variations would present themselves to those skilled in the art without departing from the scope of the various embodiments of the present invention, as described herein. The scope of the present invention is, therefore, indicated by the following claims rather than by the foregoing description. All changes, modifications, and variations coming within the meaning and range of equivalency of the claims are to be considered within their scope.

[0028] The elements and features recited in the appended claims may be combined in different ways to produce new claims that likewise fall within the scope of the present invention. Thus, whereas the dependent claims appended below depend from only a single independent or dependent claim, it is to be understood that these dependent claims may, alternatively, be made to depend in the alternative from any preceding or following claim, whether independent or dependent. Such new combinations are to be understood as forming a part of the present specification.

[0029] While the present invention has been described above by reference to various embodiments, it should be understood that many changes and modifications can be made to the described embodiments. It is therefore intended that the foregoing description be regarded as illustrative rather than limiting, and that it be understood that all equivalents and/or combinations of embodiments are intended to be included in this description.