COLLETT, Christopher, Mark (PO Box 376, Beerwah, QLD 4519, AU)
| CLAIMS 1 . A solar panel safety isolator including: one or more inward electrical connections each to which conductors may be connected to provide electrical communication between one or more solar panels and the isolator; one or more outward electrical connections each to which conductors may be connected to provide electrical communication between the isolator and a 1'oad, the or each inward electrical connection being in electrical connection with one or more of the outward electrical connections; electrical isolation means electrically interposed between the or each inward and outward connections and operable for isolating outward power supply to the or all outward electrical connections from the or all inward electrical connections; and tripping means operable to trip the electrical isolation^ means to isolate outward power supply to the or all outward electrical connections from the or all inward electrical connections, said tripping means being powered by low voltage direct current. 2 . The solar panel safety isolator according to Claim 1, wherein the tripping means includes one or more supply connections each to which conductors may be connected to • supply electrical power to a solenoid such that interruption of the supply of electrical power to the tripping means activates the tripping means to isolate the outward power supply to the or all outward electrical connections from the or all inward electrical connections. 3 . The solar panel safety isolator according to Claim 1, and including: a solenoid housed in a housing; a pair of inward, electrical conductors to provide an electrically conductive connection between a bank of solar panels and a pair of inward electrical connections which penetrate the housing of the solenoid; a pair of . outward electrical conductors to provide an electrically conductive connection between a pair of outward .electrical connections; and a set of outward contacts associated with the solenoid and which penetrate the housing of the solenoid. 4 . The solar panel safety isolator according to Claim 3, wherein a pair of bridging conductors provides a breakable electrical connection between the pair of inward connections and the pair of outward connections through the solenoid housing. 5 . The solar panel safety isolator according to Claim 4, wherein the solenoid actuates a set of contacts to make -an electrical connection between the inward and outward connections when powered by way of the power supply conductors. |
This invention relates to a solar panel safety isolator. The invention has particular application to isolation of one or more solar panels from a power supply as close electrically as is practical to the solar panel or panels. The invention also has particular application to isolation of solar panels used for domestic power supply. However, the invention also has application to safety isolation of solar panels in non- domestic applications. Solar panels have been used to supply or supplement the supply of electricity in many applications, but particularly in domestic applications. In such applications, it is normally the case that several solar panels are provided in a bank or array of panels and are connected to the power supply through an inverter. Should there be an electrical fault, ' the power supply is isolated from the fault by way of the mandated safety isolation switch.
In emergency situations, such as fire, storm or flood, damaged buildings are normally isolated from the mains supply by emergency personnel-. However, solar panels would still be active in most situations because solar panels produce electricity whenever light impinges the panels. In many situations, up to 800V is produced with enough energy to cause death ΟΓ· serious injury from electrocution. Solar panel isolation switches have been proposed which make use of a solenoid driven from a mains power supply in electromechanical connection with contacts which isolate the solar panels and short -circuit them when the solenoid is de- energised. However, such systems are normally provided on the inverter side of the circuitry. Otherwise, such systems include alternating current and direct current conductors in close proximity to one another which may result in the generation of undesirable induced currents in the direct current circuit and/or undesirable transient currents in the alternating current circuit when electrical conditions change in the direct- current circuit.
The present invention aims to. provide ' a solar · panel safety isolator which alleviates one or more of the' aforementioned problems. Other aims and advantages of the , invention may become apparent from the following description.
With the foregoing in view, in one aspect the present invention resides broadly in a solar panel safety isolator including: one or more inward electrical connections each to which conductors may be · connected to provide electrical communication between one or more solar panels and the isolator; one or more outward electrical connections each to which conductors may be connected to provide electrical communication between the isolator and a load, the or each inward electrical connection being in electrical connection with one or more of the outward electrical connections; electrical isolation means electrically interposed between the or each inward and outward connections and operable for isolating outward power supply to the or all outward electrical connections from the or all inward electrical connections; and tripping means operable to trip the electrical isolation means to isolate outward power supply to the or all outward electrical connections from the or all inward electrical connections. Preferably, the tripping means includes one or more supply . connections each to which conductors may be connected to supply electrical power to a solenoid or such like such that interruption of the supply of electrical power to the tripping means activates the tripping means to isolate the outward power supply to the or all outward electrical connections from the or all inward electrical connections.
In order that the invention may be more readily understood and put into practical effect reference will now be made to the following drawings which illustrate a preferred embodiment of the invention, and wherein:
Fig. 1 is a diagrammatic representation of a solar panel safety isolator according to the invention. The solar panel safety isolator 10 illustrated in Fig 1 includes a double pole solenoid 12 housed in a housing 11. A pair of inward electrical conductors 14 provide an electrically conductive connection between, a bank of solar panels 13 and a pair of inward electrical connections 15 which penetrate the housing of the solenoid. A pair of outward electrical conductors 16 provide an electrically conductive connection between a pair of outward electrical connections 16 The solenoid operates a set of outward contacts 16 which penetrate the housing of the solenoid and an inverter 18. The solenoid is powered by a pair of low voltage power supply conductors 19 which receive power from rectified lower power voltage source powered from the mains power supply through a transformer (not shown) . A pair of bridging conductors 21 provides a breakable electrical connection between the pair of inward connections and the pair of outward connections through the solenoid housing. The solenoid actuates a set of contacts 20 to make an electrical connection between the inward and outward connections when powered by way of . the power supply conductors. In use, one or more solar panel safety isolators according to the invention may be electrically interposed between a solar panel or a bank or solar panels. In a typical installation, the solar panel safety isolator is mounted above the roofline as close as practicable to the solar panel or panels. Until activated, all associated wiring from the solar panel safety isolator would not be energised and would therefore be safe. Of course, -other standard electrical safety devices would be installed to isolate the mains power supply according to wiring rules and standards. -
The primary purpose of the solar panel safety isolator according to the invention is safety. Firstly, the solar panel safety isolator according to the invention provides safety for the installer, of the solar panels in not having to deal with energised cables prior to completion of the job.
Secondly, in the event of a fire ■ or other building damage, when the emergency worker or householder disconnects power to the solar panel safety isolator, DC power from the solar panel or solar panel array is isolated (including above the- . roofline ) . It will be seen the solar panel safety isolator removes potentially dangerous currents inside the roof and wall cavities.
Thirdly, the solar panel safety isolator would typically be installed in conjunction the mandatory safety switch which would be tripped in the event of short circuit, earthing of a power conductor or the like whereupon the solar panel safety isolator according to the invention would likewise be tripped to isolate the supply from the solar panels as well, as the supply from the mains. The ' solar panel safety isolator according to the invention may also be used to provide an installation point for the fitting of a- circuit breaker.
It will be seen that the solar panel safety isolator according to the invention has more than one mode of operation. If the low voltage power supply to the solenoid is interrupted, the solar panels are isolated. If the mains supply to the transformer for the low voltage power supply is interrupted, the solar panels are isolated. It the mains supply itself is interrupted, the solar panels are isolated. Therefore, the solar panel safety · isolator operates according to a fail-safe principle that no matter what mode by which the solenoid is de-energised, the solar panels are isolated.
Although the invention has been described with reference to a specific and preferred example, it will be appreciated by persons skilled in the art that the invention may be embodied in other forms within the broad scope and ambit of the invention as herein set forth and defined by the following claim.