IEEE Standard Inverse-Time Characteristic Equations for Overcurrent Relays

IEEE Transactions on Power Delivery (Impact Factor: 1.73). 08/1999; 14(3):868 - 872. DOI: 10.1109/61.772326
Source: IEEE Xplore


This paper introduces the new standard “IEEE standard
inverse-time characteristic equations for overcurrent relays”. It
provides an analytic representation of typical electromechanical relays
operating characteristic curve shapes in order to facilitate
coordination when using microprocessor-type relays

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    • "In this paper, our test power system is equipped with overcurrent relays, and the inverse-time characteristics of the overcurrent relays complies with IEEE Standards [6]. The pickup time of the inverse characteristic of overcurrent relays is expressed as "
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    ABSTRACT: This paper proposes a methodology to coordinate protection relays with a VSC-HVDC link for mitigating the occurrence of cascading failures in stressed power systems. The methodology uses a signal created from an evaluation of the relay's status and simplifications of certain system parameters. This signal is sent to a Central Control Unit (CCU) which determines corrective action in order to reduce the risk of cascading failures.
    Power System Technology (POWERCON), 2010 International Conference on; 11/2010
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    • "–[12], and the simulation inverse curve formula of electromagnetic overcurrent relays [13], respectively. They are employed to derive the adjustment equations for different types of overcurrent relays (1) where t time to trip, in seconds; L time dial, or lever setting; i the secondary fault current of the current transformer, in amperes; In tap value; M multiples of pickup current, where ; "
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    ABSTRACT: This paper presents a practical and effective novel approach to solve the coordination problem caused by the curve intersection of overcurrent relays in subtransmission systems. Based on the IEEE and IEC standard characteristic curve equations of digital overcurrent relays, as well as the simulation curve equation for electromagnetic overcurrent relays, lever setting adjustment equations for a selected point on the characteristic curve is derived. Then, centered on the derived equations, a dedicated software program is developed to compute the corresponding relay lever setting with different tap value in order that, passing through the selected point, another curve with the new lever setting is chosen. Finally, assisting with the graphical capability of the commercial ASPEN OneLiner, the proposed fixed-point coordination curve adjustment procedure can completely eliminate the coordination curve intersections. In addition, an actual case of a subtransmission network in Taiwan Power Company is simulated to validate the feasibility of the technique proposed.
    IEEE Transactions on Power Delivery 11/2008; 23(4-23):1780 - 1788. DOI:10.1109/TPWRD.2008.919391 · 1.73 Impact Factor
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    • "See IEEE C37.112 -1996, IEEE Standard Inverse-Time Characteristic Equations for Overcurrent Relays, [3] "
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    ABSTRACT: The thermal limitations of induction motors are specified by thermal limit curves that are plots of the limiting temperature of the rotor and stator in units of l<sup>2</sup>t. This paper discusses the thermal protection provided by rotor and stator thermal models defined by the thermal limit curves and supporting motor data. The thermal model is the time-discrete form of the differential equation for temperature rise due to current and is derived from fundamental principles as shown in the Appendix. The rotor model derives the slip-dependent l<sup>2</sup>r watts using voltage and current that permit the safe starting of high-inertia drive motors. The performance of the models is shown in constant and cyclic load tests.
    Industrial & Commercial Power Systems Technical Conference, 2007. ICPS 2007. IEEE/IAS; 06/2007
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