A system for distribution transformer monitoring may comprise a distribution transformer that includes a transformer fluid tank, a monitoring unit that includes a plurality of sensors, wherein the monitoring unit is coupled to the distribution transformer, and wherein the plurality of sensors comprises a fluid sensor that includes a sensor probe that extends out of the monitoring unit into the transformer fluid tank of the distribution transformer, and a communication unit coupled to the distribution transformer and communicatively coupled to the monitoring unit. The monitoring unit may further comprises a sensor module to receive sensor data from the plurality of sensors, a storage module to store the sensor data in an internal data storage device of the monitoring unit, an analysis module to analyze the sensor data to determine generated data, and a communication module to communicate the sensor data or the generated data to a remote computing device.

This application discloses a photovoltaic direct-current breaking apparatus, including a positive connection terminal and a negative connection terminal for connecting a photovoltaic string and a photovoltaic energy converter, a first diode, a first switch, a convector circuit, and an energy absorption circuit, where the first switch, the convector circuit, and the energy absorption circuit are connected in parallel. The convector circuit can effectively avoid arc discharge and ablation generated when the first switch cuts off a direct-current circuit between the photovoltaic string and the photovoltaic energy converter. The first diode can effectively bypass energy stored by an energy storage device in the photovoltaic energy converter, helping reduce required specifications of a semiconductor device in the convector circuit. The energy absorption circuit can also effectively reduce required specifications of the semiconductor device and a varistor.

A method and system for predicting performance of a fluid filled electrical device are provided. The system includes a sensing unit operable communicating with a fluid level estimation system. The sensing unit includes one or more sensors physically mountable on and/or around the electrical device, recording temperature data associated with the fluid and the ambient environment. The fluid level estimation system determines temperatures of the fluid and a an ambient temperature, generates feature vectors for one or more of the temperatures based on their correlation with the ambient temperature, and estimates a fluid level inside the electrical device and thereby the performance, based on the feature vectors and a probability density function derived from a distribution constructed using historical temperature gradient data associated with the electrical device.

A method and system for predicting performance of a fluid filled electrical device are provided. The system includes a sensing unit operable communicating with a fluid level estimation system. The sensing unit includes one or more sensors physically mountable on and/or around the electrical device, recording temperature data associated with the fluid and the ambient environment. The fluid level estimation system determines temperatures of the fluid and a an ambient temperature, generates feature vectors for one or more of the temperatures based on their correlation with the ambient temperature, and estimates a fluid level inside the electrical device and thereby the performance, based on the feature vectors and a probability density function derived from a distribution constructed using historical temperature gradient data associated with the electrical device.

A system for distribution transformer monitoring may comprise a distribution transformer that includes a transformer fluid tank, a monitoring unit that includes a plurality of sensors, wherein the monitoring unit is coupled to the distribution transformer, and wherein the plurality of sensors comprises a fluid sensor that includes a sensor probe that extends out of the monitoring unit into the transformer fluid tank of the distribution transformer, and a communication unit coupled to the distribution transformer and communicatively coupled to the monitoring unit. The monitoring unit may further comprises a sensor module to receive sensor data from the plurality of sensors, a storage module to store the sensor data in an internal data storage device of the monitoring unit, an analysis module to analyze the sensor data to determine generated data, and a communication module to communicate the sensor data or the generated data to a remote computing device.

The present disclosure relates to a method of monitoring switching by an on-load tap changer (OLTC) 1 from a first contact 3a to a second contact 3b of a transformer winding 2. The method includes measuring a voltage of the transformer. The method also includes measuring a temperature of the OLTC. The method also includes, based on the measured voltage and temperature, determining whether the switching from the first contact to the second contact has been successful.