THEREOF

FIELD

The present invention relates to a distribution substation and more particularly to a system having electrical equipments integrated on a structure and to a method for providing isolation of electrical equipments.

BACKGROUND

A distribution system has an electrical substation which transfers power from the transmission system to the distribution system of a specified area or location. The electrical substation of a distribution system herein after referred as a distribution substation provides power at a voltage suitable for intermediate or local distribution. The distribution substation essentially comprises power switches which include components like circuit breakers, isolators etc and power equipments which include instrument transformers constituting current transformer and/or voltage transformer, distribution transformer. The power switches are generally used for switching on / isolating electrical equipments. It is required to de-energize the equipments to allow working on the equipments. It also clears the faults that may arise downstream.

The distribution substation is generally mounted outdoor and insulated by air, when such distribution substation involves medium and high voltages. The power switch components and power equipments in a distribution substation are mounted in outdoor on individual structures supporting them. This outdoor mounting tend to occupy more space unlike the Gas Insulated Switchgear (GIS) which is characterized by indoor mounting and gas insulation, which occupies comparatively lesser space. The space that an outdoor distribution substation occupies becomes crucial when such distribution substation is to be located in a city, where availability of land is a concern or in a hilly region, where an almost flat surface for locating the distribution substation becomes one of the most considerate requirements. This greatly influences the cost of the land required for installing such distribution substation. GIS, though occupy less space has limitation regarding the scope for expansion of the substation and is not economical for outdoor medium voltage levels, due to higher equipment cost. In general, the distribution substation mounted outdoor is still a preferred solution having regard to operating voltage level, scope for substation expansion and comparatively lower cost. Hence, there is a need for an outdoor distribution substation which occupies less space and inherits all the characteristics of the outdoor mounted distribution substation.

The present invention is aimed at providing a system having power switch components and power equipments, together along with electrical accessories including connectors, connector cables etc may hereinafter referred to as electrical equipments, integrated and located on a structure. This overcomes the disadvantages of the existing setup and provides a solution in light of the need as described earlier.

Hence the invention gives the advantage of employing the electrical equipments in an integrated manner on a structure which can be mounted in outdoor. This gives further advantage of space reduction in installing the electrical equipments of a distribution substation due to the compactness achieved by integration. The installation also requires less effort and cost.

OBJECTS OF THE INVENTION

It is an object of the invention to provide a system having electrical equipments which are integrated on a structure and are compact.

It is another object of the invention to provide a system having electrical equipments integrated on a structure which requires less cost, space, time and effort for installation. It is yet another object of the invention to provide a system having electrical equipments integrated on a structure which provides vertical and horizontal isolation of the electrical equipments.

It is a further object of the invention to provide a method for isolation of electrical equipments. SUMMARY OF THE INVENTION

Accordingly the present invention provides a system having electrical equipments integrated on a structure, the system comprising atleast one electrical equipment located at a spaced apart relationship and mounted on atleast one structure.

Accordingly the present invention also provides a method for isolation of electrical equipments, the method comprising opening and closing the contact by engaging or disengaging one or more terminals of the electrical equipments correspondingly with the supply line or the distribution line by a mechanism for isolation, wherein the said mechanism is a handle or a moving mechanism which is associated with a movement in vertical direction or horizontal direction or with a movement that provide isolation. BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the accompanying drawings in which:

Figure 1 shows a distribution substation according to the prior art.

Figure 2 shows a system according to an exemplary embodiment of the invention.

Figure 3 shows a perspective view of a system with vertical isolation according to an exemplary embodiment of the invention.

Figure 4 shows the system of figure 3 with the connectors in engaged position. Figure 5 shows the system of figure 3 with the connectors in disengaged position. Figure 6 shows the worm and worm wheel mechanism of the system of figure 3. Figure 7 shows the connectors of the system of figure 3 in engaged position.

Figure 8 shows the connectors of the system of figure 3 in disengaged position. Figure 9 shows a system with horizontal isolation according to an exemplary embodiment of the invention with the connectors in engaged position. Figure 10 shows the system of figure 9 with the connectors in disengaged position.

Figure 11 shows the roller arrangement of the moving mechanism of the system illustrated in figure 9. DETAILED DESCRIPTION

The present invention provides a system having electrical equipments, arranged in a plurality of sections. The plurality of such sections is supported on one or more of structure by way of integrating the electrical equipments and locating them on the said base structure.

It is imperative that the arrangement of electrical equipments as implied for a section and to that of the structure thereof is mechanically stable and electrically safe for operation. The invention takes cares of such mechanical stability and electrical safety requirements. Suitable reinforcement for the structure is provided, when needed, besides having the heavier components or equipments disposed at a lower level in the structure so as to ensure more mechanical stability. The electrical equipments are arranged preferably in the sequence of electrical connection with sufficient electrical clearance between various electrical equipments and with the structure for safe and reliable operation, and concurrently providing compactness for the arrangement. This corresponds to the electrical equipments being located at spaced apart relationship with each other and with the structure. Suitable insulating harriers may be provided for sufficient isolation between the electrical equipments for operational safety and also to reduce the utility of the space due to air insulation. Therefore, in accordance with the invention, a system having electrical equipments integrated on a structure is provided. The electrical equipments used herein are prefabricated and their mechanical and electrical properties have been measured and checked in advance for proper functioning prior to the installation. The electrical equipments are fixed in totality at factory and tested which involves no adjustment at the time of installation in the site. In accordance with an exemplary prior art embodiment, a distribution substation (100) in current practice as shown in figure 1 comprises of electrical equipments such as mcoming isolator (101a), circuit breaker (102), instrument transformer (103) and outgoing isolator (101b). Each of these electrical equipments are mounted on separate mounting structure and connected to each other in known sequence with sufficient clearance between them, as required for an outdoor installation. The supply line (104) and the distribution line (105) are connected thereof to each of its corresponding isolators. However, this kind of arrangement and installation occupies more space. The need for a more compact arrangement of the distribution substation is accomplished by integrating the electrical equipments of a distribution substation in which the electrical equipments as herein above mentioned are integrated together on a structure to form a system. Such integration of the electrical equipments forming a system according to different exemplary embodiments of the invention is broadly illustrated in figures 2, 3 and 9.

Figure 2 illustrates one exemplary embodiment of the invention in which the electrical equipments specifically of isolators (210a, 201b), circuit breaker (202) and instrument transformer (203) are arranged on a single frame structure (206). The supply line (204) is connected to an isolator herein referred to as an incoming isolator (201a), located on top of the single frame structure (206). The circuit breaker (202) is placed on the said single frame structure (206) at a height required to provide sufficient clearance as per the standard and one terminal of which is connected to the incoming isolator (201a). The instrument transformer (203) is also placed on the single frame structure (206) following the circuit breaker (202) with a sufficient clearance as per the standard and one terminal of which is connected to the other terminal of the circuit breaker (202). The other terminal of the instrument transformer (203) is connected to another isolator herein referred as outgoing isolator (201b) which in turn is connected to the distribution line (205) thereof. There is also provided two handles (207a, 207b), one each for incoming and outgoing isolators (201a, 201b). The handle (207a, 207b) is made use of as a mechanism for isolation by opening and closing the contact between the incoming isolator (201a) and the circuit breaker (202) and that between the outgoing isolator (201b) and the instrument transformer (203).

Figure 3 illustrates a system having electrical equipments integrated on a structure according to another exemplary embodiment of the invention. Here, the integration of the electrical equipments is effected by vertical isolation of the equipments. In accordance with this exemplary embodiment of the invention, the incoming isolator (301a) and outgoing isolator (301b) are placed on top of a single frame structure (306) and connected to the supply line (304) and the distribution line (305) respectively. One of the terminals of the incoming isolator (301a) and of the outgoing isolator (301b) is intended to make opening or closing of contact with the corresponding terminals of the circuit breaker (302) and the instrument transformer (303) thereof. The opening and closing of the contact as stated here above is effected by a mechanism purporting to vertical isolation.

The circuit breaker (302) and the instrument transformer (303) are fixed on a support structure (307) containing breaker mechanism and controls. The support structure (307) has the circuit breaker (302) and instrument transformer (303) mounted on it. The electrical equipment intended to be isolated, is capable of moving in vertical direction along the vertical axis for opening or closing the contact as described herein above by engaging or disengaging the corresponding terminals of the circuit breaker (302) with the incoming isolator (301a) and that of the corresponding terminal of the instrument transformer (303) with the outgoing isolator (301b). The isolation by using the handle (207a, 207b) as inferred from the first embodiment is done by the vertical movement of the structure.

The vertical movement is achieved with a moving mechanism primarily consisting of worm and worm wheel arrangement (311) as shown in figure 6. The worm and worm wheel arrangement (311) is located within a housing (310) and protected against atmospheric / environmental conditions like moisture, dust etc. From the illustrations of figures 3 to 5, it can be seen that the worm and worm wheel arrangement (311) is disposed at the bottom portion of a telescopic cylindrical guide (308). The upper end or portion of the telescopic cylindrical guide (308) is fixed to the bottom surface of the support structure (307) having circuit breaker (302) and instrument transformer (303). The worm and worm wheel arrangement (311) is provided with a handle (309) for operating the same in order to make movement of the telescopic cylindrical guide (308) in vertical direction along its axis. The operation of the worm and worm wheel arrangement (311) and that of the mechanism for movement thereof can be provided by any of the possible mechanism which may be manual or automated.

When the worm and worm wheel mechanism (311) is operated to effect an upward movement, the telescopic cylindrical guide (308) extends upward along with the structure (307) fixed to it being moved in vertical upward direction. This allows the corresponding terminal of the circuit breaker (302) to engage with that of the incoming isolator (301a) and similarly the terminal of the instrument transformer (303) is engaged with that of the outgoing isolator (301b) thereby closing the contact of the electrical equipments as shown in figure 4.

However, the opening of the contacts can be made by disengaging the above associated terminals. This is caused by moving the terminals of the circuit breaker (302) and the instrument transformer (303) away from the terminals of the incoming isolator (301a) and outgoing isolator (301b). This is achieved by moving the electrical equipment in vertically downward direction by operating the worm and worm wheel arrangement (311) accordingly. The electrical equipments hereby are isolated as shown in figure 5 asserting vertical isolation.

The engagement and disengagement of the connectors (400) of the circuit breaker (302) and the incoming isolator (301a) can be clearly seen and understood from figures 7 and 8. The connectors are generally used to make proper alignment of the terminals as stated throughout the description. According to another exemplary embodiment of the invention, a system having electrical equipments integrated on a structure with horizontal isolation can be inferred from figures 9 to 11. Here, the circuit breaker (502) and the instrument transformer (503) are mounted on a support structure (507) containing the breaker mechanism and controls. The terminals of the circuit breaker (502) and the instrument transformer (503) are engaged and disengaged with the con-esponding terminal of the mcorning isolator (501a) and outgoing isolator (501b), thereby opening or closing the contact with the supply line (504) and distribution line (505) by a mechanism for isolation. This is particularly done by moving the electrical equipment (502, 503) in horizontal direction for establishing such contact. The movement in horizontal direction is effected by a moving mechanism intended to be the mechanism for isolation. The moving mechanism herein referred primarily comprises a guide way (508) and an arrangement of rollers (511) at the bottom of the support structure (507) having circuit breaker (502) and instrument transformer (503). The moving mechanism for horizontal isolation may be operated manually or may be automated. For instance, automatic way of operating the moving mechanism may include motor driven mechanism for causing the movement. It is noted that the movement is a controlled movement with proper precaution for appropriate alignments between contacts, engagement and locking of the moving equipment.

The rollers (511) are aligned to move within the guide way (508), thus providing a horizontal movement. In the engaged position as shown in figure 9, in which the said structure (507) is moved to the possible position closest to the isolators (501a, 501b) and as allowed so as to make proper alignment of the connectors for engagement as herein before described. An interlock (509) is provided in the guide way (508) to lock the said structure (507) having circuit breaker (502) and instrument transformer (503), essentially to ensure proper alignment of the connectors. However, the movement of the structure (507) having circuit breaker (502) and instrument transformer (503) is arrested by a stopper pin (510) located in the guide way (508), when the said structure (507) is in its farthest position away from the isolator and being isolated. This is to ensure proper isolation. The isolation by opening and closing the contact with the supply line or with the distribution line or both is carried out by the moving mechanism. The physical act of engagement or disengagement of terminals is referred as an operation. It is to be noted that the isolation is provided between the supply line and the distribution line both together with one operation. Isolation can also be provided separately for supply line and distribution line through the same or a different mechanism through more than one operation. The concern of the size of the equipments and their ratings and the integrated setup thereof, its compactness, maintenance and its transportation are to be taken well within the scope of the invention. The structure on which the electrical equipments are mounted can be designed for adjustment in which the structure or atleast one section present in the structure is adjustable to provide flexibility of accommodating electrical equipments of different sizes, make and ratings. For instance, such adjustment could be provided by means of holed angles that can be move against one another and bolted at required positions.

The embodiments herein before described are exemplary in nature and are not exhaustive in light of the invention and are not limiting with regard to the scope of the invention and that all possible modification and alteration are to be construed well within the scope of the invention.