IEEE C37.2:2008 pdf free download

IEEE C37.2:2008 pdf free download.IEEE Standard for Electrical Power System Device Function Numbers,Acronyms, and Contact Designations.
3.1.67 Device number 67—ac directional overcurrent relay
A device that functions at a desired value of ac overcurrent flowing in a predetermined direction.
3.1.68 Device number 68—blocking or “out-of-step” relay
A device that initiates a pilot signal for blocking of tripping on external faults in a transmission line or in other apparatus under predetermined conditions or cooperates with other devices to block tripping or reclosing on an out-of-step condition or on power swings.
3.1.69 Device number 69—permissive control device
A device with two positions that, in one position permits the closing of a circuit breaker, or the placing of a piece of equipment into operation. and in the other position, prevents the circuit breaker or the equipment from being operated.
3.1.70 Device number 70—rheostat
A device used to vary the resistance in an electric circuit when the device is electrically operated or has other electrical accessories, such as auxiliary, position. or limit switches.
3.1.71 Device number 71—liquid level switch
A device that operates at a given level value, or on a given rate of change of level of a liquid.
3.1.72 Device number 72—dc circuit breaker
A device that is used to close and interrupt a dc power circuit under normal conditions or to interrupt this circuit under fault or emergency conditions.
3.1.73 Device number 73—load-resistor contactor
A device that is used to shunt or insert a step of load limiting. shiftuiig. or indicating resistance in a power circuit; to switch a space heater in circuit: or to switch a light or regenerative load resistor of a power rectifier or other machine in and out of circuit.
3.1.74 Device number 74—alarm relay
A device other than an annunciator, as covered under device function 30, that is used to operate. or that operates in connection with, a visual or audible alarm.
3.1.75 Device number 75—position changing mechanism
A device that is used for moving a main device from one position to another in equipment; f’or example. shifting a removable circuit breaker unit to and from the connected, disconnected, and test positions.
3.1.76 Device number 76—dc overcurrent relay
A device that functions when the current in a dc circuit exceeds a given value.