Abstract: A measurement method for the impedance of the converter at multiple operating points based on the secondary-side disturbance includes the following steps: superimposing the positive sequence current disturbance in the current sampling value; superimposing the positive sequence voltage disturbance in the voltage sampling value; determining whether measurement data of the converter at two or more current operating points are obtained, if so, based on the measurement data of the converter at two current operating points, calculating values of A(s) and B(s); further calculating values of coefficients at each frequency point, and obtaining the impedance value of the converter at multiple current operating points by calculation. The above-mentioned measurement method overcomes the disadvantages of high cost and complicated operation of the impedance measurement method based on the primary-side disturbance, and solves the problem of lacking the pre-judgment function.

Abstract: The present invention discloses an edge-cloud collaborative fault detection method for a low-voltage distribution network based on a random matrix theory. An edge-cloud collaborative way is adopted, including fast fault detection running in an edge IoT agent and fault timing and locating analysis running in a distribution network control center. At an edge IoT terminal, the fault is quickly detected based on time-delay correlation analysis, a long-time series model is constructed, a time series is fitted with an autoregressive moving average model, and the fault is quickly judged based on a typical value of a limit spectral density function of the time series; after the edge IoT terminal detects the fault, fault-related data are uploaded to the distribution network control center through data screening, historical data and real-time data are integrated, and a spectral deviation index is configured to perform fault timing and locating analysis.

Abstract: Provided are a method and apparatus for estimating a meteorology sensitive load power. The method includes: obtaining a meteorology sensitive load power estimation model; inputting a daily load curve of a date to be estimated to the meteorology sensitive load power estimation model and extracting a daily load curve dimension reduction feature of the date to be estimated; and outputting a meteorology sensitive load power based on the daily load curve dimension reduction feature of the date to be estimated and mapping relationships from daily load curve dimension reduction features onto meteorology sensitive load powers. The proposed estimation model can directly obtain the meteorology sensitive load power curve from the daily load curve, and is especially applicable to cases where meteorology data is frequently lost in practical applications.

Abstract: Systems and methods of heating an accurate quantity of a fluid. A determination is made that an event in which a relatively large quantity of hot water is used has occurred. One or more temperatures are sensed. An increase in a temperature set point is made if the sensed temperatures indicate a shortage of hot water for the event. A decrease in the temperature set point is made if the sensed temperatures indicate an excess of hot water was available for the event. No change is made to the temperature set point if the quantity of hot water available for the event was appropriate.

Abstract: A type of mixed energy heater with constant temperature control, which belongs to the field of water heater technology. This water heater includes a gas heating portion, an electric heating portion, and a control circuit. The control circuit includes a power output controller. The electric heating portion is composed of water passage and electric heating device installed in the water passage. The water passages of the gas heating portion and the electric heating portion are connected together in series or in parallel, and the terminal of the passage is equipped with a temperature sensor. The output of the temperature sensor is connected to the signal input of the control circuit.

Abstract: A type of mixed energy heater with constant temperature control, which belongs to the field of water heater technology. This water heater includes a gas heating portion, an electric heating portion, and a control circuit. The control circuit includes a power output controller. The electric heating portion is composed of water passage and electric heating device installed in the water passage. The water passages of the gas heating portion and the electric heating portion are connected together in series or in parallel, and the terminal of the passage is equipped with a temperature sensor. The output of the temperature sensor is connected to the signal input of the control circuit.

Abstract: Systems and methods of heating an accurate quantity of a fluid. A determination is made that an event in which a relatively large quantity of hot water is used has occurred. One or more temperatures are sensed. An increase in a temperature set point is made if the sensed temperatures indicate a shortage of hot water for the event. A decrease in the temperature set point is made if the sensed temperatures indicate an excess of hot water was available for the event. No change is made to the temperature set point if the quantity of hot water available for the event was appropriate.