2 Figure 1: Radial power system. characteristic impedance angle. 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’. ElectricalPartManuals . www . In fact, the directional line can neither be plotted on the relay forward fault characteristic nor the relay reverse fault characteristic graphs. We know that I 0 = (Ia + Ib + Ic) / 3. Similarly to a directional earthing relay, the characteristic angle of a directional phase relay defines the position of the angular tripping zone. 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. 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 … com. The travel of the moving contacts can be adjusted by adjusting the angle of rotation of the disc. The relay consists mainly of I … 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. A run time of up to 60 seconds appears to be the maximum … Directional Over Current Relay. B. Relay Characteristic Angle The Relay Characteristic Angle (RCA) setting is used in ‘Phase angle’Operation mode. 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. Characteristic Angle is also called Directional angle as it decides the direction of operation of the relay. The basic principles of directional relays and the construction of their electromagnetic types. 1. This angle is different for phase faults and earth faults. 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 . 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. It is the impedance angle commonly referred to as the maximum torque angle (MTA). The differences between the various models covered by this instruction book are shown in Table 1. With its flexible directional boundary definition it is also perfect for testing the characteristic of steady-state ground fault relays. This is expected fault angle, and completely predictable. 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. This p roduces a retarding effect on … 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. 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. STANDARD IDMT OVERCURRENT PROTECTION RELAYS. Directional relay senses direction of power flow by means of phase angle between V and I. If the power flow is in the opposite direction, the relay will not operate. By 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 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 If the relay ‘detects fault’ and current leads VR (= Vp), then inhibit the relay tripping. o Directional overcurrent relays may not operate during stressed system conditions until after a many-second time delay. Directional Static Overcurrent Relays: For obvious reasons of obtaining selectivity overcurrent relays are made directional. Normally, the conventional over current relay (non-direction) will act for fault current in any direction. In order to be able to measure the fault direction, the polarisation variable (the voltage) must have a sufficiently high value. 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… 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. 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 . 4. com. Although directional relays have been applied successfully for many years, several new and unique applications and power system disturbances present challenges. 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. 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. 9170900990 Rev H BE1-67 Introduction i INTRODUCTION This instruction … 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. In order to be able to measure the fault direction, the polarisation variable (the voltage) must have a sufficiently high value. Leave a comment on this post, we will send you the Overcurrent Fundamental. It is the angle between the normal to the tripping plane and the polarisation variable. 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. The characteristic angle is the phase angle by which reference or polarising voltage is adjusted such that the directional relay operates with maximum sensitivity. Relays with this principle are called directional relays. Maximum torque angle is the angle made by fault current with respect to its phase voltage. Thus modeling the relays in power flow based contingency analysis is important. Maximum torque angle is the angle made by fault current with respect to its phase voltage. 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. Close-up of an induction-type overcurrent unit, showing the disc rotor and drag magnet. ElectricalPartManuals . Overcurrent protection can have a directional or non-directional trip characteristic. 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. […] 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 setting, most commonly known as Maximum Torque Angle (MTA) or Relay Characteristic Angle (RCA), is the basis … pdf. Using field and laboratory data, this paper reviews fundamentals, discusses the limits to sensitivity, and shows how and why directional element designs have progressed. Similarly to a directional earthing relay, the characteristic angle of a directional phase relay defines the position of the angular tripping zone. XXX XXX XXXXX R Publication: 9170900990 Revision: H 08/07 www . Setting of the scale-constant Is. Characteristic Angle is also called Directional angle as it decides the direction of operation of the 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. Typical transient stability practice in WECC has simulation times that seldom exceed 30 seconds for a faulted condition. Each directional stage has instantaneous (start) forward/reverse outputs available. 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. Most ground directional overcurrent relays can be thought of as having two components, a directional component and an overcurrent component. 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°. 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. It is the angle between the normal to the tripping plane and the polarisation variable. DIRECTIONAL OVERCURRENT RELAY BE1-67 P0048-37 DEGREES CHARACTERISTIC ANGLE 90 0 TIME INST OVERCURRENT DIRECTIONAL BE1-67 Serial No. You can assume that if the forward angle drifts based on reactance, then a similar drift will happen in the opposite direction. 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. XXXXXXXXXXXX Style No. The single stage trip characteristic of non-directional, maximum-overcurrent time protection is shown in Figure 2 and functions as described above. In [9] A new design of Overcurrent relay OCR by using FPGA and present the type of IDMT for OCR protection . 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. 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