From current setting we calculate the trick current of the relay. These spreadsheets below will make your endless calculations much more easier. How to know if you set the correct current on a motor. Normally setting for overload is 5% until 10 % more than fla. Multiple analog outputs from an sel701 motor protection relay using a programmable logic controller. The quick setting procedure does not calculate the earthfault protection and undercurrent protection settings.
Protection relay setting checks alarm and trip settings at some point during commissioning, the alarm and trip settings of the relay elements involved will require to be entered andor checked. We also can setting overload relay value depend on value of service factor motor. Differential protective relay is a protective relay that functions on a percentage or phase angle or other quantitative difference of two currents. Motor protection relay 1mrs 755111 setting calculation tool, instructions for use rem 610 3. Motor protection fundamentals motor protection agenda. Enter the values for the motor and current transformers motor settings. For protection of motor, we have to identify the various causes of failure and to address the same. Press blue button contacts relay tripped relay not tripped. Cts having the same ratio are installed in all the connections to the. Identification of the abnormal conditions mentioned is made by the protection relays, which operate to separate the faulty part of the network from the rest of the plant. Since the protection relay should be perfectly matched to the protected motor and capable for sustained overload protection, a range of great protection relay adjustments is desirable. However, the presence of bypass switches and owners standards may require the use of load side motor protection. The protection relay setting must be calculated to give the plant the. The relay type nm10 can be used for protection of smallmedium size motors in lv and mv systems.
The imm 7960 and 7990 series of relays have been specifically designed to ensure the electrical protection of high voltage and large low voltage motors. Motor protection relay 1mrs 755111 setting calculation tool, instructions for use rem 610 2. Selection of the protection system for machines and plants. Optimizes motor protection relay thermal and fault protection settings by stanley e. Modular, compact design overcurrent reduction setting for maintenance dynamic thermal modeling 4line. For lrg systems, the pickup for the relay on the main breaker is generally at 10% of the maximum single linetoground fault current. This often leads to questions and confusion about the applicability of motor protection relays to variable frequency systems. Protection selectivity is partly considered in this report, and could be also revaluated. Mohammed tawfeeq overcurrent protective relays overcurrent relays overcurrent relaying is the simplest and cheapest type of protection used for protection of lines, transformers, generators and motor. Motor protective relays have the following functions built in. Iaictliac 60 field relay power system device function numbers a relay that functions on a given or abnormally low value or failure of machine field current, or on an excessive value. Differential relaying provides selectivity by providing a zone of protection with a circuit of interconnected cts.
Relay settings calculations electrical engineering. Sel701 motor protection relay schweitzer engineering. Overcurrent relay setting model for effective substation. The basic function of a protective relay is to identify the fault and isolate faulty part from the healthy part of the system. Application of multifunction motor protection relays to. Technical guide protection criteria for medium voltage. Designed for medium voltage motors, the 469 delivers advanced protection with customizable overload curves and single ct differential protection for added flexibility.
Obtaining information on lockout conditions from the sel701 motor protection relay. The tripping curves cold or warm starting, 3 phases and 2 phases are shown in the main catalog. The calculation of the corrected rated current of the motor, and the corrected startup current of the. Motor protection unit advanced motor protection model for larger, complex motors.
This model must account for all thermal processes in the motor while motor is starting, running at normal load, running overloaded and if motor is stopped. Protection systems applied to these may be broadly classified as unit and nonunit protection systems. The primary protective element of the motor protection relay is the thermal overload element and this is accomplished through motor thermal image modeling. Lower settings are possible if the relay disregards the transient component or if a time delay longer than the transient time 615cy is added. Undervoltage tripping with bus vts in the sel701 motor protection relay. The menu facilitates moving between the different parts of the program. However, this isnt usually the best choice for motors. For example, one electromechanical relay is adjustable from 2 to 48a pickup. A relay that functions to prevent overheating of the field excitation winding by reducing or interrupting the excitation of the shunt field.
Comprehensive motor protection relays have been in use for. I over load current in feeder load current x relay setting. This technical report refers to the electrical protections of all 2kv switchgear. Scope the present document discusses the effect of power factor pf correction of 3phase asynchronous motors on the settings of motor protection relays. In large building electrical systems, protection relays are used for. The method can be easily implemented in a protection relay test set 14, in order to facilitate the task for the test engineer. Setting the sel701 motor relay thermal element using the rating method. The basic element in overcurent protection is the overcurrent relays. Normally for overload relay setting depend on fla full load ampere of motor. Medium voltage products technical guide protection. Psm and tms settings that is plug setting multiplier and time multiplier setting are the settings of a relay used to specify its tripping limits. Overcurrent relay setting model for effective substation relay coordination international organization of scientific research 27 p a g e associated with temperature rise of the equipment whose permissible limit is based on insulation class and material problems. Provides current and temperature protection, data logging, and metering. Relay setting calculationidmt relayprotectionelectrical.
In order to understand the presented testing methods some basic. Principles of differential relaying the restraint characteristic suppose further that there is 0. For more detail setting,please refer manual guide of motor from manufacture. The best method for providing overcurrent protection for most circuits is to use a circuit breaker that combines overcurrent protection with shortcircuit and groundfault protection. Until recently the relays for applications 1 and 2 would have been induction disc relays as mentioned above and those for application 3 would have been thermallyactivated relays. These settings may be revaluated during the commissioning, according to actual and measured values. Overcurrent protection fundamentals relay protection against high current was the earliest relay protection mechanism to. Overcurrent protection fundamentals r ced engineering. Settings relay word bits 51p1p 51p1t 51p1r controls the torque control switch pickup curve timeout reset torque control switch setting 51p1p i. If we clear the concept for these relays first then understanding the numerical relay settings becomes easy. Motor protection relay setting guide free ebook download as pdf file. In these calculations, the resistance can be ignored since it is small in comparison with. Where the complete scheme is engineered and supplied by a single contractor, the settings may already have been entered prior to despatch from the. To understand this concept easily, it is better to know about settings of the electromechanical relays.
This interval is measured between relays in serie s eithe r at the instantaneous setting of the load sid e feeder circuit breaker relay or the maximum shortcircuit current, which can flow through both dev ices simultaneously, whichever is the lower value of current. Protective relaying philosophy and design guidelines pjm. This model must account for thermal process in the motor while motor is starting, running at normal load, running overloaded and stopped. This permits the use of the same time multiplier setting for several relays in series. Motor protection circuits s bharadwaj reddy august 1, 2017 july 9, 2018 an essential component of any highpower motor control circuit is some device to detect a condition of excessive overload and interrupt power to the motor before thermal damage occurs. But it is depend on operation and functional of motor. Please share some relay setting calculations excels, pdf or doble or rio test kit calculation files if you have any so that we could purchase it on this website. Main menu the main menu opens when the program is started. However if motors are designed with a service factor, which is then shown on the nameplate eg. We will set this value or digital relays calculate that from network specifications that. Referring to characteristic curves below, read time multiplier setting where 10 times plug setting current and 2. Verify that the minimum 3phase fault current at the motor terminals is at least 3 times the relay setting. Feeder circuit protection electrical plant protection motor protection. Protective relays sense system current and voltage levels to determine both the presence and location of.
Failure of a motor can have a severe impact on the process and overall cost effectiveness of the plant. For that, we have to first divide primary faulty current by ct ratio to get relay faulty current. Step3 now we have to calculate psm for the specified faulty current level. Motor protection relay for high voltage induction motor. The nature of relay thermal overload curves and how the relay uses them modern micro. The relays are built to be self protecting in the event of an overload until the short circuit protection device is activated. The setting is in pickup amperes, completely independent of the pickup setting of the inversetime element or, on some solidstate relays, in multiples of the inversetime pickup point. In this video we have explained calculation for idmt over current relay setting calculation. Technical explanation for motor protective relay omron. Principles of differential relaying setting a low z diff relay settings generically defined as follows.
The primary motor protective element of the motor protection relay is the thermal overload element and this is accomplished through motor thermal image modeling. Principles of differential relaying my protection guide. Motor thermal capacity used how does the relay know r1. Stator and is separate from the overload model for calculating thermal. The problem is that you have to anticipate that drop when setting the overcurrent mustoperate value for the motor protective relay. Motor protection fundamentals ali kazemi, pe regional technical manager schweitzer engineering laboratories. Motor control and protection major features and benefits the sel710 motor protection relay provides an exceptional combination of protection, monitoring, control, and communication in an industrial package. This presentation delt with motor protection relay and its setting creteria.
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