Method for connecting an energy generation installation to a medium voltage network and energy generation installation

Patent metadata

Field	Value
Publication number	US-10186872-B2
Application number	US-201715715573-A
Country	US
Kind code	B2
Filing date	Sep 26, 2017
Priority date	Mar 27, 2015
Publication date	Jan 22, 2019
Grant date	Jan 22, 2019

Abstract

A method for connecting an energy generation installation to a medium-voltage grid includes determining a calibration factor for adjusting first voltage values to second voltage values by a controller of the energy generation installation. During an idle state of a medium-voltage transformer, the first voltage values are detected at a capacitive voltage divider, arranged on the medium-voltage side of the medium-voltage transformer, and the second voltage values are detected by a voltage detection means, arranged on the low-voltage side of the medium-voltage transformer. The method further includes closing a circuit breaker arranged on the medium-voltage side of the medium-voltage transformer by the controller of the energy generation installation, when voltage values determined at the capacitive voltage divider exceed a first threshold value after the calibration factor has been applied.

First claim

The invention claimed is:

1. A method for connecting an energy generation installation to a medium-voltage grid, comprising:
determining a calibration factor for adjusting first voltage values to second voltage values by a controller of the energy generation installation, wherein, during an idle state of a medium-voltage transformer, the first voltage values are detected at a capacitive voltage divider, arranged on the medium-voltage side of the medium-voltage transformer, and the second voltage values are detected by a voltage detection means, arranged on the low-voltage side of the medium-voltage transformer, and
closing a circuit breaker arranged on the medium-voltage side of the medium-voltage transformer by the controller of the energy generation installation, when voltage values determined at the capacitive voltage divider exceed a first threshold value after the calibration factor has been applied.

2. The method as claimed in claim 1 , wherein the first voltage values are amplified by means of an amplifier.

3. The method as claimed in claim 2 , wherein the amplified first voltage values are transmitted to the controller of the energy generation installation by means of an analog data transmission circuit.

4. A photovoltaic installation, comprising:
a photovoltaic (PV) inverter connected on an input side thereof to a photovoltaic generator and its output connected without a switch in-between to a low-voltage side of a medium-voltage transformer,
a capacitive voltage divider arranged on a medium-voltage side of the medium-voltage transformer configured to detect first voltage values,
a voltage detection circuit arranged on the low-voltage side of the medium-voltage transformer for detecting second voltage values,
a circuit breaker arranged on the medium-voltage side of the medium-voltage transformer and configured to connect the output of the PV inverter to a medium-voltage grid,
a calibration unit configured to adjust the first voltage values to the second voltage values during an idle state of the medium-voltage transformer,
a controller configured to actuate the circuit breaker when voltage values detected at the capacitive voltage divider and adjusted by the calibration unit exceed a first threshold value.

5. The photovoltaic installation as claimed in claim 4 , further comprising an amplifier configured to amplify the first voltage values.

6. The photovoltaic installation as claimed in claim 5 , further comprising an analog data transmission circuit configured to transmit the amplified first voltage values to the controller of the photovoltaic installation.

7. The photovoltaic installation as claimed in claim 4 , wherein the controller comprises the calibration unit.

Assignees

• Sma Solar Technology Ag

Inventors

• Falk Andreas

Classifications

• G05F1/10

  Regulating voltage or current  (G05F1/02 takes precedence) · CPC title

• H02J3/14 Primary

  by switching loads on to, or off from, the networks, e.g. progressively balanced loading · CPC title

• H02M7/54

  by dynamic converters · CPC title

• H02J2101/24

  Photovoltaics · CPC title

• Y02E10/563

  Cross-Sectional Technologies · mapped topic