Patent ID: 8952825
Filing Date: 2015-02-10
Classification: H02H,H02S,Y02E

Abstract:
1. Monitoring device for an ungrounded electric network of a photovoltaic system having: a short circuit measuring circuit which comprises a first electric measuring circuit conductor extending from a first electric pole of the photovoltaic system to a connection node for connecting the first electric pole of the photovoltaic system with a grounded reference point, the first electric measuring circuit conductor including at least one protective component, and a second electric measuring circuit conductor extending from a second electric pole of the photovoltaic system to said connection node for connecting the second electric pole of the photovoltaic system with said reference point, the second electric measuring circuit conductor including at least one other protective component, wherein both measuring circuit conductors are directly connected to each other by said connection node to form a mutual short at said reference point between the first and the second electric poles of the photovoltaic system, said first electric measuring circuit conductor further including a first component for measuring an electric parameter in the first electric measuring circuit conductor being integrated in the first short circuit measuring conductor of the short circuit measuring circuit, said second electric measuring circuit conductor further including a second component for measuring an electric parameter in the second electric measuring circuit conductor being integrated in the second short measuring circuit conductor of the short circuit measuring circuit, and a measuring device for measuring an electric parameter of the first component, wherein an electric fault between the photovoltaic system and the reference point can be detected in response to a value of the parameter non-zero and/or a change of the value of the parameter wherein the measuring device is designed for measuring the electric parameter of the first and the second component, wherein the electric parameter is the electric voltage dropping at the first or second component or the current flowing through the first or second component, and wherein the measuring device measures at three measuring points, including before the second component, between the first and second components, and behind the first component.