A safety shut-down system for a solar energy installation includes a DC to AC inverter converting DC power from a photovoltaic solar array to AC power and generating remote control signals to enable or disable the flow of DC power from each individual photovoltaic panel or string of panels to a photovoltaic output circuit. One or more manual switches, one of which may be at a service entrance for electrical power to the installation, are operative to cause the DC to AC inverter to disable all DC power from the photovoltaic solar array; this also occurs when the DC to AC inverter is shut off. A storage battery may selectively receive DC power from one or more photovoltaic panels or strings of panels for charging. The DC to AC inverter may generate AC power from the battery when the photovoltaic solar array is disabled.

A remote-controlled photovoltaic string combiner is described that selects strings to be combined to a first photovoltaic output circuit or to a second photovoltaic output for the purpose of either controlling the charging of a battery connected to the first photovoltaic output circuit or for diverting current to a diversion load such as a grid-tie inverter. Strings are selected by energizing relays from one or other inverter such that when neither inverter is operating, all strings are deselected and both photovoltaic output circuits are de-energized.

A multi-time frame distribution planning system which provides capacity planning and distributed energy resource planning is disclosed. In an embodiment, the system includes an interface for receiving electric power system input data for a plurality of data inputs including distributed energy resource data inputs and a data store including the electric power system input data. A computer processor coupled to the data store is programmed, upon receiving one or more commands, to use the electric power system input data to calculate at least one 3-phase AC power flow. The processor is further programmed to use the at least one 3-phase AC power flow to create at least one AC optimal power flow and use the AC optimal power flow to generate at least one potential scenario that includes distributed energy resources or hosting capacity for distributed energy resources.

An improved residential electrical energy system is described based on the use of a smart load center or power distribution panel configured to select the use of utility power or power derived from storage batteries independently for each of a number of load circuits based on availability of utility power and battery charge state information.

A method and circuit arrangement is described for start-up and shut-down of high power DC to AC inverters which limits inrush current for capacitor charging, reduces input and output relay contact stress and discharges internal capacitors upon shut down. A preferred inrush limiting component has a higher resistance when hot than when cold, such as an incandescent filament lamp.

A power source and power management system including: a controller configured to transmit tracking information of the power source and power management system; an energy harvesting power source; a non-degrading rechargeable power source electrically connected to the energy harvesting power source and configured to be recharged by energy generated by the energy harvesting power source; and a power manager configured to control switching of a system power source between the energy harvesting power source and the non-degrading rechargeable power source based on a power state of the energy harvesting power source and a power state of the non-degrading rechargeable power source

An adaptive electrical power distribution panel receives electrical power from at least an alternative power source other than a utility electric grid, and selectively outputs power to a plurality of branch circuits, appliances, or devices. An internal or remote controller monitors conditions. In response to the monitored conditions, the controller algorithmically divides the plurality of branch circuits, appliances, or devices into a first group to receive power from the alternative power source and a second group to not receive power from the alternative power source, and breaks electrical connections between the alternative power source and the second group. The monitored conditions may include operating parameters the grid; an instantaneous or average individual current flow; and a charge state of storage batteries. The division into groups may also be in response to stored information, such as a priority of, or history of current usage by, each branch circuit, appliance, or device.

A DC to AC converter is described in which DC power presented as a set of relatively floating DC power sources of differing DC voltage values is converted to a desired AC power waveform by combining the DC voltage values with sequential sets of associated ternary-valued multiplicative weights of +1, 1, or 0, and summing the weighted voltage values, so as to produce voltage points on the desired waveform at appropriate time instants.

An improved solar energy utilization system is described based on the use of a smart load center which can automatically select the use of utility power or solar-derived power independently for each of a number of load circuits based on availability of utility and solar power, preset user priorities, battery charge status, time of day, instantaneous consumption, historical consumption patterns and weather forecasts.

An adaptive electrical power distribution panel receives electrical power from at least an alternative power source other than a utility electric grid, and selectively outputs power to a plurality of branch circuits, appliances, or devices. An internal or remote controller monitors conditions. In response to the monitored conditions, the controller algorithmically divides the plurality of branch circuits, appliances, or devices into a first group to receive power from the alternative power source and a second group to not receive power from the alternative power source, and breaks electrical connections between the alternative power source and the second group. The monitored conditions may include operating parameters the grid; an instantaneous or average individual current flow; and a charge state of storage batteries. The division into groups may also be in response to stored information, such as a priority of, or history of current usage by, each branch circuit, appliance, or device.