Abstract: A first plate-like portion is provided with a plurality of first holes extending therethrough in a central axis direction. A second plate-like portion is provided with a plurality of second holes extending therethrough in the central axis direction. The plurality of first holes, the plurality of second holes, a first notch and a second notch overlap one another, to thereby form a flow path which connects one side and the other side of each of a plurality of insulating plates and through which insulating oil can flow in a first direction.

Abstract: The present invention is directed to a method of estimating an overheating temperature of an oil-immersed electric appliance in which ester oil is used as insulating oil. The overheating temperature is estimated based on a first concentration ratio representing a concentration ratio between two types of gas components contained in the ester oil and a second concentration ratio representing a concentration ratio between other two types of gas components contained in the ester oil. The first concentration ratio and the second concentration ratio are selected from a concentration ratio between acetylene and ethane, a concentration ratio between acetylene and hydrogen, a concentration ratio between acetylene and methane, and a concentration ratio between acetylene and ethylene.

Abstract: The present invention is directed to a method of estimating an overheating temperature of an oil-immersed electric appliance in which ester oil is used as insulating oil. The overheating temperature is estimated based on a first concentration ratio representing a concentration ratio between two types of gas components contained in the ester oil and a second concentration ratio representing a concentration ratio between other two types of gas components contained in the ester oil. The first concentration ratio and the second concentration ratio are selected from a concentration ratio between acetylene and ethane, a concentration ratio between acetylene and hydrogen, a concentration ratio between acetylene and methane, and a concentration ratio between acetylene and ethylene.

Abstract: The present invention is a diagnosis method for internal fault of an oil-immersed electric apparatus using a silicone oil as an insulating oil. The method diagnoses an internal fault of the oil-immersed electric apparatus based on a first concentration ratio that is a concentration ratio between two gases selected from an analysis gas group consisting of hydrogen gas, methane gas, ethane gas, and ethylene gas contained in the, silicone oil, and a second concentration ratio that is a concentration ratio between the other two gases selected from the analysis gas group. A combination of the two gases and a combination of the other two gases are a combination of ethylene gas and hydrogen gas, a combination of ethane gas and hydrogen gas, a combination of ethylene gas and methane gas, or a combination of methane gas and ethane gas.

Abstract: The present invention is a diagnosis method for internal fault of an oil-immersed electric apparatus using a silicone oil as an insulating oil. The method diagnoses an internal fault of the oil-immersed electric apparatus based on a first concentration ratio that is a concentration ratio between two gases selected from an analysis gas group consisting of hydrogen gas, methane gas, ethane gas, and ethylene gas contained in the, silicone oil, and a second concentration ratio that is a concentration ratio between the other two gases selected from the analysis gas group. A combination of the two gases and a combination of the other two gases are a combination of ethylene gas and hydrogen gas, a combination of ethane gas and hydrogen gas, a combination of ethylene gas and methane gas, or a combination of methane gas and ethane gas.