Remotely accessible power controller for building lighting

#This invention relates generally to electrical load controllers for saving energy in commercial buildings, and in particular to a remotely accessible power controller for automatically disconnecting building lighting loads to comply with energy consumption codes applicable to the automatic shutoff of electrical lighting, and for automatically disconnecting or dimming building lighting loads to limit total connected power consumption below an agreed level in accordance with load curtailment agreements with public or private utility companies.

#In an effort to make more efficient use of available energy resources, government authorities are adopting and mandating building energy codes. In particular, many jurisdictions have adopted the International Energy Conservation Code (IECC) which references ASHRAE/IESNA Standard 90.1 for commercial buildings. Part III (3) of that standard, concerning interior lighting, requires that all commercial buildings more than 5000 square feet in size must be equipped with automatic lighting shutoff in all spaces, by using time of day controls, occupancy sensor controls or other automatic controls that do not require operator intervention, so that energy can be saved during hours when the spaces are not occupied.

#Modern building control systems generally allow an operator to control various operating systems from a centralized or remote building control station. For example, the building operator can monitor and exercise control over lighting systems, HVAC (heating, ventilation and air conditioning), water and waste disposal, furnaces, cooling towers, heat exchangers, ventilation dampers, fire detection and alarm systems, security cameras and other building service equipment. Such controls are implemented to maintain a customized set of building services to satisfy the comfort, safety and business needs of building tenants according to leasehold agreements.

#The accompanying drawing is incorporated into and forms a part of the specification to illustrate the preferred embodiments of the present invention. Various advantages and features of the invention will be understood from the following detailed description taken with reference to the attached drawing figures in which:

#FIG. 1 is a block diagram showing a power line carrier (PLC) network power controller for a three-phase lighting control system in which load reduction command signals are received from on-site and remote command control centers;

#FIG. 2 is a block diagram showing a power line carrier (PLC) network power controller for a two-phase lighting control system in which load reduction command signals from on-site and remote command control centers control dimming and non-dimming lighting loads;

#A preferred embodiment of the invention will now be described with reference to various examples of how the invention can best be made and used. Like reference numerals are used throughout the description and several views of the drawing to indicate like or corresponding parts.

#Referring now to FIG. 1 and FIG. 2, the power controller circuit 10 of the present invention will be described with reference to a typical AC power distribution system commonly used for 110 volts, 60 Hz AC power service, in which AC power is conducted via hot, neutral and ground safety power line conductors 12, 14 and 16, respectively in either three phases A, B and C (FIG. 1), or two phases A and B, (FIG. 2). The power lines of most electrical power distribution systems conduct alternating current (AC) at a selected operating voltage (e.g., 110 VAC, 120 VAC or 220 VAC) and power distribution frequency (usually 60 Hz in the U.S. and 50 Hz elsewhere) via one or more phases (e.g., single-phase, two-phase or three-phase service) supplied by a private or public utility company. The AC power is applied to multiple lighting loads, both dimming and non-dimming as shown in FIG. 2, that may be connected in separate load groups A, B and C located, for example, in an office building that is subject to a mandatory building energy code, for example the International Energy Conservation Code (IECC) which references ASHRAE/IESNA Standard 90.1.

#The power line conductors are insulated aluminum or copper wire conductors, typically 12 AWG Romex copper. Line 12, commonly known as the “hot” line, may be a black color-coded wire and line 14, referred to as the “neutral” line, may be a white color-coded wire. The neutral line is connected to earth ground by the ground safety conductor 16. For each phase, AC power is then distributed over lines 12 and 14 with the neutral line 16 providing a ground at each load. Generally, a main circuit breaker is used for each phase in addition to branch circuit breakers in each power distribution branch. In some cases a separate ground wire is not used to provide a ground connection. Instead, a ground return path is obtained from a metallic conduit, water pipe or the like.