o Directional overcurrent relays may not operate during stressed system conditions until after a many-second time delay. the relay has an approximate maximum torque angle characteristic of 45 degrees lead (current leads voltage), the directional unit will develop maximum operating torque when the fault current lags its unity power-factor position by about 45 degrees. Directional Characteristic Angle of Directional Overcurrent Relays in Transmission Networks José Jaramillo Serna Universidad de Antioquia ... and more specifically, the determination of the directional characteristic angle, to the application of the so-called typical settings. Maximum torque angle is the angle made by fault current with respect to its phase voltage. This directional over current relay employs the principle of actuation of the relay, when the fault current flows into the relay in a particular direction. The scale constant I s is equal to the rated current Ir times the sum of the set value of the switches S1:1, S1:2 and S1:3 plus 0,1. Directional overcurrent ground relays may be set sensitive enough to detect these faults with minimal effects on security due to the fact that transmission networks are inherently designed such that zero sequence currents created by system imbalances are minimized. Leave a comment on this post, we will send you the Overcurrent Fundamental. Overcurrent is used for automatic testing of directional and non-directional overcurrent relays with auto-assessment of the trip time characteristic, the directional boundaries of the current stages, and the pick-up/drop-off ratio. ElectricalPartManuals . Maximum torque angle is the angle made by fault current with respect to its phase voltage. This angle is different for phase faults and earth faults. Characteristic Angle is also called Directional angle as it decides the direction of operation of the relay. V Relay maximum torque The maximum torque angle (MTA) is defined as the angle by which the current applied to the relay must be displaced from the voltage applied to the relay to produce maximum torque. 18 FUNDAMENTAL RELAY-OPERATING PRINCIPLES AND CHARACTERISTICS Time delay is obtained in induction-type relays by a "drag magnet," which is a permanent magnet arranged so that the relay rotor cuts the flux between the poles of the magnet, as shown in Fig. You can assume that if the forward angle drifts based on reactance, then a similar drift will happen in the opposite direction. The characteristic angle is the phase angle by which reference or polarising voltage is adjusted such that the directional relay operates with maximum sensitivity. In order for a trip to occur, the magnitude of the operate quantity exceeds the threshold limit for a specific duration and the direction of the fault must be within the operate (trip region) characteristic for a trip decision. The so-called “directional” or zero-torque line was used with old impedance relays that had a separate supervising directional element, or with directional overcurrent relays and incorrectly carried over to R-X graphs for modern relays. Directional Over Current Relay. directional overcurrent relays, such as the relay characteristic angle, the selection of the polarizing quantities (negative sequence or zero sequence) for the directional ground overcurrent protection function, and the minimum thresholds for the activation of the voltage memory for the directional phase overcurrent element. A run time of up to 60 seconds appears to be the maximum … www . It is the impedance angle commonly referred to as the maximum torque angle (MTA). […] XXXXXXXXXXXX Style No. It is the angle between the normal to the tripping plane and the polarisation variable. 1. ElectricalPartManuals . In the previous post about Directional Overcurrent relay (67) testing (Finding the Direction in Directional Overcurrent Relays), we reviewed Directional Overcurrent protection from a system perspective to enhance the descriptions in The Relay Testing Handbook: Principles and Practice.We’ll be looking at Directional Overcurrent relays from a testing perspective in this post. XXX XXX XXXXX R Publication: 9170900990 Revision: H 08/07 www . Similarly to a directional earthing relay, the characteristic angle of a directional phase relay defines the position of the angular tripping zone. The ‘discrimination principle’ based on phase angle comparison between a set of phasors, one of which is used as reference is called ‘Directional Discrimination Principle’. characteristic impedance angle. In fact, the directional line can neither be plotted on the relay forward fault characteristic nor the relay reverse fault characteristic graphs. Overcurrent protection can have a directional or non-directional trip characteristic. Although the relay element may be inherently wattmetric, its characteristic can be varied by the addition of phase shifting components to give maximum torque at the required phase angle… The travel of the moving contacts can be adjusted by adjusting the angle of rotation of the disc. In [9] A new design of Overcurrent relay OCR by using FPGA and present the type of IDMT for OCR protection . Similarly to a directional earthing relay, the characteristic angle of a directional phase relay defines the position of the angular tripping zone. With its flexible directional boundary definition it is also perfect for testing the characteristic of steady-state ground fault relays. Close-up of an induction-type overcurrent unit, showing the disc rotor and drag magnet. Using field and laboratory data, this paper reviews fundamentals, discusses the limits to sensitivity, and shows how and why directional element designs have progressed. ABB Relays Design Type RXPE 40 00 directional overcurrent relay The RXPE 40 is a static, single-phase, voltage- polarized ac directional overcurrent relay mo- dule which measures the component of current that has a phase angle equal to the designed characteristic angle. While directional earth fault also uses the concept of a relay characteristic angle to determine direction, it looks at a different vector value to conventional overcurrent: the zero sequence component. Directional relay senses direction of power flow by means of phase angle between V and I. Directional Static Overcurrent Relays: For obvious reasons of obtaining selectivity overcurrent relays are made directional. 4. Directional Overcurrent Relays Types IBC, IBCG And mcv ,DEVICE FUNCTION NUMBERS FOR USE WITH EXTERNAL DIAGRAMS 52 Power Circuit Breaker 67 - Directional Overcurrent Relays, Type mc or Type mcv 67N - Directional Ground Relay, Type mCG a - Auxiliary Contact, 0;> en when Breaker Opens Dill - Directional Unit SI - Seal-in Unit with Target Characteristic Angle is also called Directional angle as it decides the direction of operation of the relay. The differences between the various models covered by this instruction book are shown in Table 1. The reason that Directional overcurrent has a “Relay Characteristic Angle” or “Torque Angle” (a legacy term), is to account for the reactance of your network. DIRECTIONAL OVERCURRENT RELAY BE1-67 P0048-37 DEGREES CHARACTERISTIC ANGLE 90 0 TIME INST OVERCURRENT DIRECTIONAL BE1-67 Serial No. In order to be able to measure the fault direction, the polarisation variable (the voltage) must have a sufficiently high value. com. By The relay consists mainly of I … Setting of the scale-constant Is. 36 PROTECTIVE RELAY TYPES 3 CURRENT, VOLTAGE, DIRECTIONAL, CURRENT (OR VOLTAGE)-BALANCE, AND DIFFERENTIAL RELAYS Chapter 2 described the operating principles and characteristics of the basic relay elements. The current/time-tripping characteristics of IDMT protection relays may need to be changed according to the functioning time needed and the characteristics of other relay protection elements used in the electrical network0.10 For these needs, IEC 60255 determined … Non-directional Induction Overcurrent Relay Construction: ... the disc rotates and moving contacts on spindle make the connection with trip circuit terminals.The angle through which the disc rotates is between 0° to 360°. 9170900990 Rev H BE1-67 Introduction i INTRODUCTION This instruction … In order to be able to measure the fault direction, the polarisation variable (the voltage) must have a sufficiently high value. Relay characteristic angle (directional protection) Polarizing Voltage Threshold (directional protection) 2nd element Definite Time Tripping characteristic 3 X CT Pick-up 3 x I n CT primary 100 ms Trip time delay Table 1: Relay parameters for this example . Directional time-overcurrent relay 1MRK 509 025-WEN Version 2.1 Replaces - 1MRK 509 025-WEN Page 2 ABB Network Partner AB Version 2.1 SETTINGS: All settings can be changed while the relay is in normal service. B. Relay Characteristic Angle The Relay Characteristic Angle (RCA) setting is used in ‘Phase angle’Operation mode. pdf. If the power flow is in the opposite direction, the relay will not operate. This p roduces a retarding effect on … STANDARD IDMT OVERCURRENT PROTECTION RELAYS. In this article, we explain some of the concepts behind directional earth fault, sharing our experience to support field deployment of this valuable protection element. This setting, most commonly known as Maximum Torque Angle (MTA) or Relay Characteristic Angle (RCA), is the basis … Most ground directional overcurrent relays can be thought of as having two components, a directional component and an overcurrent component. 2 Figure 1: Radial power system. com. If the relay ‘detects fault’ and current leads VR (= Vp), then inhibit the relay tripping. Three-phase Directional Overcurrent (67) Each one of the three-phase overcurrent stages of the P127 can be independently configured as directional protection with specific relay characteristic angle (RCA) settings and boundaries. It is the angle between the normal to the tripping plane and the polarisation variable. We know that I 0 = (Ia + Ib + Ic) / 3. All protective-relay types are derived either directly from these basic elements, by combining two or more of these elements in the same enclosing case or in the same … A 360 degree setting range is used to adjust the directional element operation according to the method of neutral point grounding. Typical transient stability practice in WECC has simulation times that seldom exceed 30 seconds for a faulted condition. n GE JBC Phase Directional Overcurrent Relay • Uses quadrature polarizing voltage • Has an MTA of 45 degrees • Has a pickup of 2VA at MTA • Has a directionally controlled instantaneous unit . Although directional relays have been applied successfully for many years, several new and unique applications and power system disturbances present challenges. However, in a system with multiple sources or parallel paths, we require earth fault relays to be directional as discussed in earlier post How to Incorporate Directional Featurein a Relay.. As we discussed in earlier post How to Incorporate Directional Feature in a Relay, that for making a Relay directional we need Reference Phasor. This is expected fault angle, and completely predictable. Normally, the conventional over current relay (non-direction) will act for fault current in any direction. The basic principles of directional relays and the construction of their electromagnetic types. While Directional Earth Fault also uses the concept of a Relay Characteristic Angle to determine direction, it looks at a different vector value to conventional overcurrent: The Zero Sequence Component. Relays with this principle are called directional relays. In this article, we explain some of the concepts behind directional Earth Fault, sharing our experience to support field deployment of this valuable protection element. Thus modeling the relays in power flow based contingency analysis is important. Each directional stage has instantaneous (start) forward/reverse outputs available. 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