A method, an apparatus, and a system for monitoring an islanding electricity generation unit are provided. The method includes determining an islanding electricity generation unit in a renewable energy station on the basis of collected electrical capacity at critical electrical nodes of the renewable energy station, and controlling a switch device corresponding to the determined islanding electricity generation unit to sever connection between the electricity generation unit and a collector line. The critical electrical nodes include nodes that have a collecting effect on grid-connected current of the electricity generation units of the renewable energy station, and each collector line being constructed to collect grid-connected current from at least one electricity generation unit and input same into a main transformer of the renewable energy station.

To ensure safety of people needing to service a low-voltage network of an electric power distribution system, dwellings being connected to this network may include autonomous units for producing electricity, thus generating voltage and endangering the people servicing the work. Data are obtained from consumption records from the meter of each dwelling, in regular time intervals, and meteorological data are also obtained in the geographical area of these dwellings, in order to identify at least some weather conditions conducive to the production of energy by autonomous units. A model is then applied for detecting, based on the first and second data, a coincidence between periods of lower consumption measured by a meter and weather conditions conducive to electricity production by autonomous units during these periods. Therefore, information on the presence of autonomous units in the dwelling can be deduced and given to people before their servicing.

A distributed power system wherein a plurality of power converters are connected in parallel and share the power conversion load according to a prescribed function, but each power converter autonomously determines its share of power conversion. Each power converter operates according to its own power conversion formula/function, such that overall the parallel-connected converters share the power conversion load in a predetermined manner.

Systems, apparatuses, and methods are described for discharging an input voltage by utilizing discharge circuitry configured to produce a relatively constant discharge voltage value/output voltage, a relatively constant discharge current value/output current, or a relatively constant discharge power value/output power. The discharge circuitry may include at least one power device, such as a DC to DC converter.

Power generation devices and methods for use with toilets is disclosed. A number of power generation devices are provided that can be used in combination to power various features in a toilet which will be particularly useful for portable toilets that are off the grid. The power generation devices and methods include, for example, using a cell battery inside a toilet water source, a wind turbine, solar panels, and piezoelectricity. The features include, for example, lighting up the toilet with light-emitting diodes (LEDs) to make it easier for users to find the toilet, an audio/video setup for entertainment, and a toilet status light indicator to let the next user know when the toilet paper is out.

A method for determining when a connection of a power system to a grid has been disconnected. The method includes the power system supplying a first amount of reactive power to the grid to which the power system is connected, and the power system determining if there is a frequency change within the grid. This includes if the frequency change does not exceed a predetermined threshold, the power system supplying a second amount of reactive power to the grid, and if the frequency exceeds a predetermined threshold, the power system supplying a first amount of reactive power to the grid.

A method and apparatus for tertiary control with over-current protection. In one embodiment, the method comprises calculating at least one unconstrained optimal net intertie target for an area of a power network; calculating, for each resource within the area, optimal scheduled current to achieve the at least one unconstrained optimal net intertie target; calculating, using the optimal scheduled currents and a plurality of stress coefficients, net scheduled current for each power line segment within the area; comparing the net scheduled currents to corresponding stress thresholds to identify any stress violations; reducing, when the comparing step identifies one or more stress violations, the optimal scheduled current for one or more resources contributing to the one or more stress violations; and calculating, when the comparing step identifies the one or more stress violations, updated optimal scheduled current for one or more resources not contributing to the one or more stress violations.

A system for distributing locally generated energy from at least one renewable DC source to a plurality of local load units of the system, including, for each load unit: an input terminal configured to connect to a grid, and an output terminal configured to connect to at least one load. Further for each load the system includes an inverter including an inverter input and an inverter output, wherein the inverter input is connected to the at least one renewable DC source and the inverter output is connected to the input terminal and to the output terminal of the respective load unit, and wherein the inverter is configured to convert a direct current at the inverter input into an alternating current at the inverter output. The system also includes a power meter including a power meter input connected to the input terminal of the respective load unit, wherein the power meter is configured to determine a current power consumption from the grid, and wherein the power meter includes a power meter output connected to the inverter of the respective load unit, and wherein the power meter is configured to transmit data relating to the current power consumption from the grid to the inverter. The inverter of the respective load unit is configured to determine an input DC voltage applied to its inverter input and to determine a power to be currently converted from the applied input DC voltage and the current power consumption data transmitted thereto.

In a control device, an instruction acquirer acquires an instruction to suppress in a specified period supplying of generated power generated by power generator installed in a power-consuming area to a commercial electrical power system. Upon the instruction acquirer acquiring the instruction, a water heater controller commands a water heater installed in the power-consuming area to perform a water heat-up operation when a predetermined condition is satisfied in the specified period.

A method and apparatus is described for conveying the amount of loading of a power source to a load control device by controlling the frequency of the AC power output from that power source in a manner that controlled frequency represents the loading. At a different location in the power system, the frequency is measured and the corresponding loading of the power source is used to prevent or alleviate a power source overload.