Power-network note, variable transformer and method of operating the node

Patent metadata

Field	Value
Publication number	US-10211627-B2
Application number	US-201515110119-A
Country	US
Kind code	B2
Filing date	Feb 18, 2015
Priority date	Feb 24, 2014
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

A network node for a substation or a local network station has a control transformer with a primary side and a secondary side, an input line connected to the primary side, and an output line connected to the secondary side. A protective switch is provided in the input line or in the output line, and a sensor detects an electrical parameter in the input line or in the output line and generate a measurement signal. A controller coupled to the control transformer, to the protective switch, and to the sensor, serves to operate the control transformer in dependence on the measurement signal such that the control transformer has a predetermined transmission ratio and open the protective switch in dependence on the measurement signal as soon as the control transformer has the predetermined transmission ratio.

First claim

The invention claimed is:

1. A network node for a substation or a local network station, the node comprising:
a control transformer with a primary side and a secondary side;
an input line connected to the primary side;
an output line connected to the secondary side;
a protective switch in the input line or in the output line;
a sensor for detecting an electrical parameter in the input line or in the output line and generate a measurement signal; and
a controller coupled to the control transformer, to the protective switch, and to the sensor, and serving to
operate the control transformer in dependence on the measurement signal such that the control transformer has a predetermined transmission ratio, and
open the protective switch in dependence on the measurement signal as soon as the control transformer has the predetermined transmission ratio.

2. The network node according to claim 1 , further comprising the step of:
the controller opening the protective switch after operation of the control transformer.

3. The network node according to claim 1 , further comprising the step of:
the controller the protective switch prior to or simultaneously with operation of the control transformer, the node further comprising:
delay means coupled to the protective switch for delaying opening of the protective switch.

4. The network node according to claim 1 , further comprising;
an overvoltage protective circuit having
the protective switch in the input line;
two input connections; and

two further protective switches that each connect a respective one of the input connections to an end of the input line not connected to the primary side.

5. The network node according to claim 1 , further comprising:
a filter coupled to the input line or to the output line and being a dynamic filter or an active filter; or
a capacitor bank connected to the input line or to the output line; or
an energy accumulator coupled to the input line or to the output line and having an electrical energy accumulator or a chemical energy accumulator or a thermal energy accumulator or a compressed air reservoir.

6. A control transformer for a network node of a power grid, the network node comprising:
a primary side and a secondary side;
an input line connected to the primary side;
an output line connected to the secondary side;
a protective switch in the input line or in the output line;
a sensor for detecting an electrical parameter in the input line or in the output line and generate a measurement signal;
a regulator for changing a transmission ratio; and
a controller coupled to the regulator, to the protective switch, and to the sensor, and serving to
control the regulator in dependence on the measurement signal such that the control transformer has a predetermined transmission ratio and
open the protective switch in dependence on the measurement signal as soon as the control transformer has the predetermined transmission ratio.

7. The control transformer according to claim 6 , further comprising:
a primary side overvoltage protective circuit having the protective switch in the input line;
two input connections; and
two further protective switches that each connect a respective one of the input connections to an end of the input line that is not connected to the primary side.

8. The control transformer according to claim 6 , further comprising:
a housing holding
an active part of the control transformer,
the regulator, and

the protective switch or a primary side overvoltage protective circuit.

9. The control transformer according to claim 6 , wherein
the control transformer has an internal temperature sensor for generating a temperature signal, or a pressure sensor for generating a pressure signal; and
the controller is coupled to the temperature sensor or to the pressure sensor and serves to open the protective switch in dependence on the temperature signal or in dependence on the pressure signal.

10. A method of operating a network node for a power grid wherein the network node comprises
a control transformer with a primary side and a secondary side;
an input line connected to the primary side;
an output line connected to the secondary side; and
a protective switch in the input line or in the output line;

the method comprising the steps of:
monitoring an electrical parameter in the input line or in the output line and,
if the parameter meets an error criterion, then
controlling the control transformer in dependence on the parameter such that the control transformer has a predetermined transmission ratio, and
opening the protective switch in dependence on the parameter as soon as the control transformer has the predetermined transmission ratio.

11. The method according to claim 10 , further comprising the steps of:
sending a first control signal to the control transformer controlling the control transformer; or
sending a second control signal or the first control signal to the protective switch on opening the protective switch.

12. The method according to claim 11 , wherein the second control signal is sent after the first control signal is sent.

13. The method according to claim 11 , further comprising the steps of:
sending the second control signal prior to or simultaneously with sending the first control signal, and
delaying opening of the protective switch.

14. The method according to claim 10 , further comprising the steps of:
monitoring a temperature or a pressure inside of the control transformer; and,
if the monitored temperature meets an error criterion or if the monitored pressure meets an error criterion, opening the protective switch.

Assignees

• Reinhausen Maschf Scheubeck

Inventors

• Sachsenhauser Andreas
• Kaltenborn Uwe
• Schuster Thomas

Classifications

• H02H7/055 Primary

  for tapped transformers or tap-changing means thereof · CPC title

• H02H7/26 Primary

  Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured (locating faults in cables G01R31/08) · CPC title

• H02H7/04 Primary

  for transformers · CPC title

• H02H3/20

  responsive to excess voltage · CPC title