Transformer arrangement

Patent metadata

Field	Value
Publication number	US-11757368-B2
Application number	US-202017639117-A
Country	US
Kind code	B2
Filing date	Dec 18, 2020
Priority date	Dec 20, 2019
Publication date	Sep 12, 2023
Grant date	Sep 12, 2023

Abstract

A transformer arrangement is provided. The transformer arrangement includes a transformer with a primary and a secondary winding and a chain link of switching blocks connected in series between one of the windings and a load, where the switching blocks comprise a first set of voltage contribution blocks and a second set of circuit breaker blocks, where the first set of voltage contribution blocks is configured to adjust a voltage output by the transformer with an offset voltage and the second set of circuit breaker blocks is configured to interrupt a current running through the chain link.

First claim

The invention claimed is:

1. A transformer arrangement comprising:
a transformer with a primary and a secondary winding; and
a chain link of switching blocks connected to one of the secondary windings and connectable in series between said one of the windings and a load, said switching blocks comprising a first set of voltage contribution blocks and a second set of circuit breaker blocks, where the first set of voltage contribution blocks is configured to adjust a voltage output by the transformer with an offset voltage and the second set of circuit breaker blocks is configured to interrupt a current (I load ) running through the chain link, wherein at least some of the blocks are grouped into cells, each cell comprising at least one voltage contribution block and at least one circuit breaking block.

2. The transformer arrangement according to claim 1 , wherein the chain link is connected to a first end of the transformer winding and connectable between the first end of the transformer winding and a first end of the load.

3. The transformer arrangement according to claim 1 , wherein the chain link is connected to a second end of the transformer winding and connectable between the second end of the transformer winding and a second end of the load, where the second end of the transformer winding is a grounding end.

4. The transformer arrangement according to claim 1 , where the voltage contribution block is a bipolar voltage contribution block having a first energy storage element for short-term energy supply.

5. The transformer arrangement according to claim 4 , wherein the first set of voltage contribution blocks is controllable to provide a positive or negative voltage contribution at a 90 degrees phase angle to the load current for injecting or withdrawing reactive power using the first energy storage element.

6. The transformer arrangement according to claim 4 , wherein the bipolar voltage contribution block comprises a second energy storage element for long-term energy supply.

7. The transformer arrangement according to claim 6 , wherein the first set of voltage contribution blocks is controllable to provide a positive or negative voltage contribution in a range of 0-360 degrees to the load current in order to inject or withdraw active power using the second energy storage element.

8. The transformer arrangement according to claim 1 , wherein first set of voltage contribution blocks is controllable to regulate harmonics and/or flicker in the voltage output by the transformer.

9. The transformer arrangement according to claim 1 , wherein the second set of circuit breaking blocks is controllable to interrupt the current through the chain link based on the detection of a fault.

10. The transformer arrangement according to claim 1 , wherein the number of voltage contribution blocks are selected for a desired voltage range of a voltage adjustment to be made to the voltage across the corresponding transformer winding for magnitude control or voltage phase control and the number of circuit breaker blocks are selected for achieving a desired current interrupting level.

11. The transformer arrangement according to claim 1 , wherein the transformer is a three-phase transformer comprising a primary side and a secondary side with primary and secondary windings, where each side comprises three windings and where there is an equal number of chain links, each connected to a corresponding winding of one of the sides.

12. The transformer arrangement according to claim 11 , wherein said one side is wye connected, where each chain link is connected to a first end of the corresponding winding of said one side, with the second end of each winding being connected to a neutral.

13. The transformer arrangement according to claim 12 , wherein said one side is delta-connected, where each chain link is connected to a first end of the corresponding winding of said one side, with the second end of each winding being connected to a chain link of another winding.

14. The transformer arrangement according to claim 1 , further comprising a control unit configured to control the switching blocks of the chain link.

15. The transformer arrangement according to claim 1 , wherein each circuit breaker block of the second set of circuit breaker blocks comprises:
a first end providing a first connection terminal;
a second end providing a second connection terminal;
a mechanical switch connected between the first connection terminal and the second connection terminal;
a main breaker connected in parallel with the mechanical switch, the main breaker comprising one or more electronic switches; and
a surge arrestor connected in parallel with the main breaker and the mechanical switch,
wherein a control unit closes the mechanical switch during steady state operation and when current interruption is required:
opens the mechanical switch to commutate current over to the breaker;
opens the main breaker to commutate current over to the surge arrestor where the current is quenched.

16. The transformer arrangement according to claim 15 , wherein each circuit breaker block of the second set of circuit breaker blocks further comprises:
a snubber string connected in parallel with the main breaker and the mechanical switch, the snubber string comprising a capacitor in series with a resistor.

17. The transformer arrangement according to claim 15 , wherein each of the one or more electronic switches comprises at least one of an insulated-gate bipolar transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET), a bi-mode insulated gate transistor (BIGT), or junction field effect transistors (JFETs).

18. The transformer arrangement according to claim 1 , wherein each voltage contribution block of the first set of voltage contribution blocks comprises:
a first string of electronic switches comprising two electronic switches connected to each other and a midpoint between the two electronic switches provides a first connection terminal of the voltage contribution block; and
a second string of electronic switches comprising two electronic switches connected to each other and a midpoint between the two electronic switches provides a second connection terminal of the voltage contribution block.

19. The transformer arrangement according to claim 18 , wherein each voltage contribution block of the first set of voltage contribution blocks further comprises an energy storage element connected in parallel with the first string of electronic switches and the second string of electronic switches.

20. The transformer arrangement according to claim 18 , wherein each of the one or more electronic switches comprises at least one of an insulated-gate bipolar transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET), a bi-mode insulated gate transistor (BIGT), or junction field effect transistors (JFETs).

Assignees

• Hitachi Energy Switzerland Ag

Inventors

• Alves Roberto
• Chen Nan
• Dijkhuizen Frans
• Svensson Jan
• Nami Alireza

Classifications

• H02M1/32 Primary

  Means for protecting converters other than automatic disconnection · CPC title

• H01H9/548 Primary

  Electromechanical and static switch connected in series · CPC title

• H02M5/12 Primary

  for conversion of voltage or current amplitude only · CPC title

• H02M5/44

  using discharge tubes or semiconductor devices to convert the intermediate DC into AC · CPC title

• H02M5/4585

  having a rectifier with controlled elements · CPC title