Description

The invention is related to a modular high voltage supply system, comprising a mobile adapter transformer with a high-voltage output side and a low-voltage input side, wherein electrical connecting input-terminals for the input-side are foreseen at the outer surface of the mobile adapter transformer, further comprising a mobile container with a low voltage supply system mounted stationary therein which comprises a high current busbar and at least one electrical frequency converter connected thereto, wherein electrical connecting output-terminals for the high current busbar are foreseen at an accessible edge of the mobile container and further comprising a modular interim busbar system for the temporary electrical connection of input- and output- terminals.

It is known that synchronous generators are used for the conversion of mechanical into electrical energy. Dependent on the frequency of rotation and the excitation of the rotor winding of the synchronous generator a voltage with a corresponding height and frequency will be generated. Such a variable power source might be required as auxiliary power supply in a power plant for example.

The rated power of such variable auxiliary power supplies with rotating generators might be around 12MVA / 4MW for example wherein the rated output voltage might amount 10kV. In the case that such a generator is not ready for operation during a certain time, for example due to scheduled maintenance or a breakdown, a prompt replacement is required in order to supply the respective loads with electric energy of the desired voltage and frequency anyhow.

But also for purposes of testing of electrical equipment such as high power transformers, for example with a rated power of 100MW and above, a variable power source might be required. For the test of such large components it is more common to transport the test equipment to the component to be tested instead of transporting the component to the test equipment.

Disadvantageously within the state of the art is that the transport of a variable power source with rotating generator is rather difficult and time consuming due to its high weight and size. In case of a temporary installation for test purposes it has also to be ensured, that a suitable groundwork is available at the installation site of the generator.

Based on this state of the art it is objective of the invention to provide a mobile variable power supply within the power range of a few MVA and above which is easy to transport and to mount on site.

This problem is solved by a modular high voltage supply system of the aforementioned kind. This is characterized in that the modular interim busbar system comprises at least one interim busbar with at least one elongated busbar basic module mounted on a frame structure and respective resilient electrical connection means on both ends of the busbar basic module which form an electrical connection to the input- respectively output- terminals and which are arranged in a way, that a transmission of vibrations from the mobile adapter transformer to the mobile container is suppressed.

Basic idea of the invention is to replace a rotating generator by a variable power electronic based electrical frequency converter which is arranged with further components such as VAR compensators or the like in a container and which is easy to transport therewith. Since the output voltage of typical frequency converters is in the range of 400V - whereas the required output voltage might amount 10kV - a mobile adapter transformer is foreseen for adapting the voltage level accordingly. In some cases such adapter transformer might already be available on site without the need for transportation. Dependent on the needs on site it is also possible to provide a mobile adapter transformer with an output voltage of for example 6kV instead of 10kV. So the whole modular high voltage supply system comprises two main components which preferably are both mounted in a respective container, for example a standard 6m or 12m container, and which are easily to transport on site therewith.

After placing those components on site - preferably close together in a neighboring position - the container with the low voltage supply system and the adapter transformer have to become electrically connected. The low voltage supply system itself is foreseen to be supplied by an electrical supply on site which can be assumed to be available in a power plant or on a test site. Due to the low output voltage of approximately 400V of the low voltage supply system and due to the high rated power of for example 12MVA the electrical connection to the adapter transformer has to be foreseen for current levels in the range of 1000A and above. Furthermore the electrical connection has to be as flexible as possible in order to enable a variable positioning of the container with the LV supply system and the adapter transformer.

According to the invention a modular interim busbar system is foreseen for this connection. A busbar can easily be designed for sufficient high currents by increasing its cross section respectively. The base module of the interim busbar is a preferably electric insulating frame structure with an elongated busbar basic module mounted thereon. This might be designed as a massive bar from an electric conducting material. Since the power supply is typically three phased also the modular interim busbar system is preferably three phased and comprises three interim busbars.

A busbar or a busbar module is made for example from copper or aluminum. This are rather stiff materials, so a transmission of vibrations - for example 50/60Hz respectively 60/120Hz generated by the adapter transformer - to the container with the LV power supply is afforded therewith in a disadvantageously way. In order to suppress the transmission of vibrations inbetween adapter transformer and container of LV supply system resilient electrical connection means are foreseen on both ends of the busbar basic module. Such resilient electrical connection means have a spring characteristic at least in the direction of one degree of freedom in movement. So, in case that the two resilient electrical connection means on both ends of the busbar basic module are arranged with different orientations respectively perpendicular each to each other, a transmission of vibrations is suppressed in an advantageous way. Dependent on the concrete geometrical arrangement also one single resilient electrical connection means might be sufficient.

The resilient electrical connection means are connected electrically in series with the base module and further modules of the busbar, so that an electrical connection in- between the input- and the output- terminals is gained therewith. Preferably a set of modules with different selectable sizes is provided so that variable distances can be bridged therewith by mounting the modules individual according to the requirements on site. The electrical connecting output-terminals for the high current busbar of the container are for example accessible over a closeable opening at the side wall of the container, so that it can be closed during transportation.

According to a further embodiment of the invention a resilient electrical connection means comprises a first and second resilient elongated plate-like clamping element which are arranged opposed each to each other in a clamping distance and which both are electrical active part of an interim busbar. Such an embodiment provides on one side a sufficient high spring characteristic and is on the other side rather easy to mount.

According to a further embodiment of the invention both ends of the opposed clamping elements comprise a respective electrical contact section wherein a respective further electrical active section of the interim busbar is clamped between. Preferably the further electric active section of the busbar has a comparable thickness like the busbar base module, so the clamping is simplified therewith.

According to a preferred embodiment of the invention opposed elongated clamping elements are connected together by means of screws or bolts extending through the respective contact sections and through the respective electrical active section of the interim busbar clamped inbetween, which are provided with respective boreholes accordingly. By screws or bolts a sufficient high pressure can be applied on the components to be connected so that the connection complies with required electrical char- acteristics. Furthermore such a kind of connection is easily solvable so that a temporary installation of a modular high voltage system can easily dismounted.

According to another variant of the invention elongated clamping elements are made at least predominantly from copper or aluminum. This is suitable conductor material for conducting a high electrical current.

According to a further embodiment of the invention two or more neighbored clamping elements are arranged in parallel in the same plane instead of a single clamping element. This facilitates mounting the resilient electrical connection means in an advantageous way.

According to a further embodiment of the invention the modular interim busbar comprises an electrical active elongated square-shaped hollow busbar section. A weight reduction of the interim busbar is gained therewith in an advantageous way.

According to another variant of the invention the input terminals of the mobile adapter transformer are extending into the elongated square-shaped hollow busbar section in a form-locking manner. By adapting the inner square shape of the hollow busbar to the preferably square shaped outer diameter of the input terminals the electrical connection is facilitated therewith.

According to a further embodiment of the invention resilient electrical connection means are extending into the elongated square-shaped hollow busbar section in a form-locking manner. By adapting the inner square shape of the hollow busbar to the preferably square shaped outer diameter of resilient electrical connection means the electrical connection is facilitated therewith.

According to another embodiment of the invention the input terminals or the resilient electrical connection means extending into the elongated square-shaped hollow busbar section are connected thereto by means of screws or bolts. By screws or bolts a sufficient high pressure can be applied on the components to be connected so that the connection complies with required electrical characteristics. Furthermore such a kind of connection is easily solvable so that a temporary installation of a modular high voltage system can easily dismounted.

According to a further embodiment of the invention the elongated square-shaped hollow busbar section is made at least predominantly from aluminum. A further weight reduction is gained therewith in an advantageous way.

According to a further embodiment of the invention the modular interim busbar system comprises three interim busbars wherein the respective busbar basic modules are arranged within the frame structure in a horizontal and vertical distance each to each other. By arranging the basic modules diagonally the interim busbars can be mounted in an easier way since they are better accessible.

According to a further embodiment of the invention the mobile container with the low voltage supply system comprises a cooling system. For a rated power of for example 10MVar installed several frequency converters of a lower rated power are required which are arranged phase wise and also in parallel. To ensure that the heat losses are dissipated from the inner of the container a cooling system, for example with condenser and evaporator, is foreseen.

According to a preferred embodiment of the invention the mobile container is a standard container according to CSC (Container Safety Convention) standard. Several transport systems exist for those kinds of containers, such as trucks, trains and ships so that a transportation of the low voltage supply system in such a container is facilitated therewith.

Further advantageous embodiments of the invention are mentioned in the dependent claims.

The invention will now be further explained by means of an exemplary embodiment and with reference to the accompanying drawings, in which:

Figure 1 shows an exemplary modular high voltage supply system,

Figure 2 shows first exemplary resilient electrical connection means, Figure 3 shows second exemplary resilient electrical connection means,

Figure 4 shows an elongated square-shaped hollow busbar section,

Figure 5 shows a low voltage supply system in a mobile container,

Figure 6 shows a mobile container on a truck and

Figure 7 shows a mobile adapter transformer on a truck.

Figure 1 shows an exemplary modular high voltage supply system 10 from a side view. A mobile adapter transformer 12 with a rated voltage of 400V on its input side and 10kV on its output side is temporarily arranged on a ground floor 40. On the top of the adapter transformer 12 an oil expansion vessel 14, lifting lugs 18 and three input terminals 1 6 for the electrical connection of the input side are foreseen. Respective output terminals 22 for the 10kV output side for the supply of electrical loads are indicated with an arrow.

An exemplary vibration source 22 in the center of the adapter transformer indicates operational vibrations of 50Hz and an integer multiple therefrom, which are rising during the operation of the adapter transformer.

Neighbored and in parallel to the adapter transformer 12 a mobile container 24 with a low voltage supply system is temporarily placed on the ground floor 40. The container 24 comprises three output terminals 26 for its inner high-current busbar, which are arranged diagonal behind an opening of the outer side wall.

A modular interim busbar system 28 is foreseen for the temporary electrical connection of the output terminals 26 of the container 24 with the input terminals 1 6 of the adapter transformer 12. The modular interim busbar system 28 comprises a frame structure 30 from aluminum bars with three elongated busbar basic modules 32 mounted thereon in an electrical insulating manner. On one end of the respective busbar basic modules 32 first resilient electrical connection means 34 are attached, which form an electrical connection to the output terminals 26 of the container 24. Due to the modular structure of the interim busbars several resilient electrical connection means 34 with different length are available, so that dependent on the requirements on site resilient electrical connection means 34 with a respective suitable size are selectable. On the respective other ends of the busbar basic modules 32 second resilient electrical connection means 36 are attached, which are part of an electrical connection to the input terminals 1 6 of the adapter transformer 12. The other end of the second resilient electrical connection means 36 is connected to a respective elongated square-shaped hollow busbar section 38, which is electrically connected with the input terminals 16.

Due to the spring characteristic of the first 34 and second 36 resilient electrical connection means of the modular interim busbar system 32 the transmission of vibrations from the adapter transformer 12 to the container 24 is suppressed in an advantageous way.

Figure 2 shows first exemplary resilient electrical connection means 50 in a cross sectional view. A first 52 and a second 54 resilient elongated plate-like clamping element are arranged opposed each to each other in a clamping distance 60 and are both electrical active part of an interim busbar. At both ends of the opposed clamping elements 52, 54 a respective electrical contact section 56, 58 is foreseen wherein respective further electrical active sections 62, 64 of the interim busbar are clamped between. Screws 66 are foreseen for connecting the opposed elongated clamping elements 52, 54 together and apply a pressure force thereon. The screws 66 are extending through holes of the respective contact sections 56, 58 and through the respective electrical further active section 62, 64 of the interim busbar clamped inbe- tween. The spring characteristic of the resilient electrical connection means is indicated with an arrow 68.

Figure 3 shows second exemplary resilient electrical connection means 70 from a birds view. Two neighbored clamping elements 72, 74 are arranged in parallel in the same plane. At their both axial ends the clamping elements 72, 74 are connected with a first 76 and a second 78 further electrical active section of a respective interim busbar. Screws 80 are foreseen for connecting the opposed elongated clamping elements 52, 54 together and apply a pressure force thereon. Figure 4 shows an elongated square-shaped hollow busbar section in a three dimensional view.

Figure 5 shows a low voltage supply system in a mobile container 102 in a sketch 100. The low voltage supply system comprises a high current busbar 104 which is connected to output-terminals 106 at an opening 108 at the outer side of the container 102. Three electrical frequency converters 1 12, 1 14, 1 1 6 and a VAR compensator are connected to the busbar 104. The converters 1 12, 1 14, 1 1 6 are electrically supplied by a busbar for high voltage supply, which can be connected to an external high voltage supply system. A cooling system 1 10 is foreseen for to ensure that the heat losses are dissipated from the inner of the container.

Figure 6 shows a mobile container 132 with a low voltage supply system on a truck 134 in a sketch 130.

Figure 7 shows a mobile adapter transformer 142 on a truck 144 in a sketch 140.

List of reference signs

10 exemplary modular high voltage supply system

12 mobile adapter transformer

14 oil expansion vessel

16 input terminals for input side of adapter transformer

18 lifting lugs

20 output terminals for output side of adapter transformer

22 vibration source

24 mobile container

26 output-terminals for busbar of container

28 modular interim busbar system

30 frame structure

32 elongated busbar basic modules

34 first resilient electrical connection means of modular interim busbar system

36 second resilient electrical connection means modular interim busbar system

38 elongated square-shaped hollow busbar section

40 ground floor

50 first exemplary resilient electrical connection means

52 first resilient elongated plate-like clamping element

54 second resilient elongated plate-like clamping element

56 electrical contact section of first resilient clamping element

58 electrical contact section of second resilient clamping element

60 clamping distance

62 first further electrical active section of interim busbar

64 second further electrical active section of interim busbar

66 exemplary screws

68 direction of resiliency

70 second exemplary resilient electrical connection means

72 first neighbored resilient elongated plate-like clamping element

74 second neighbored resilient elongated plate-like clamping element

76 first further electrical active section of interim busbar

78 second further electrical active section of interim busbar

80 screws

90 elongated square-shaped hollow busbar section 100 low voltage supply system in container

102 mobile container

104 high current busbar

106 output-terminals for busbar of container

108 opening

1 10 cooling system

1 12 first electrical frequency converter

1 14 second electrical frequency converter

1 1 6 third electrical frequency converter

1 18 VAR compensator

120 busbar for high voltage supply

130 mobile container on truck

132 mobile container with low voltage supply system

134 truck

140 mobile adapter transformer on truck

142 mobile adapter transformer

144 truck