Wire protection method and wire protection device

摘要

With a wire protection method in accordance with the present invention, the method being used for supplying electric power from a power source to a load, an applied-current to the load is detected every predetermined time, A wire rise temperature is calculated using the detected applied-current I(n) and by a relational expression concerning heat radiation and heat generation of the wire. The calculated rise in temperature is added to a reference temperature so that a wire temperature is estimated. When the estimated wire temperature is lower than a predetermined upper limit temperature, the calculation of the rise in temperature is repeated. When the estimated wire temperature has become equal to or higher than the predetermined upper limit temperature, the electric power supply from the power source to the load is stopped so that the wire is protected.

主权项

1. A wire protection method of protecting a wire used for supplying electric power from a power source to a load, the method comprising the steps of:
detecting an applied-current to the load every predetermined time; estimating a temperature of the wire, wherein the estimating includes: calculating a rise in temperature of the wire from a reference temperature based on heat generation and heat radiation of the wire due to the detected applied-current per the predetermined time; and adding the wire rise temperature to the reference temperature; determining whether the estimated wire temperature is lower than a predetermined upper limit temperature; newly estimating the wire temperature upon determination in the determining step that the estimated wire temperature is lower than the predetermined upper limit temperature, wherein the newly estimating includes: calculating a new rise in temperature of the wire from the reference temperature using the rise in temperature, the new rise in temperature based on the heat generation and the heat radiation of the wire due to a newly detected applied-current per the predetermined time; and adding the new wire rise temperature to the reference temperature; and stopping the electric power supply from the power source to the load upon determination in the determining step that the estimated wire temperature is equal to or higher than the predetermined upper limit temperature.