Power system protection

A motor with “208 volts” in the voltage field with the 230/460 V points, then the motor must meet efficiency and NEMA amps and torques also at the 208 V point. If the current value is supplied, it means the motor can run at 208 V without overheating. If the field is blank, the motor is not suitable to operate at the nameplate power at 208 volts 20 Insulation class (CLASS) Insulation classes are expressions of the thermal tolerance of the motor winding, or the winding’s ability to survive a given operating temperature for a given life. The classes are designated in order of thermal capabilities by the letters A, B, F and H. The higher the designated code letter, the greater the heat capability. For example, based on a 40°C ambient temperature, class B insulation is suitable for 80°C rise by resistance, class F suitable for 105°C rise by resistance, and class H is suitable for 125°C rise by resistance. Use of class F or class H insulation can increase the service factor or the ability to withstand high ambient temperature conditions. Class A and B systems are now rarely, if ever, used in industrial motors. It should be noted that a higher insulation class does not necessarily mean that the motor operates at that higher temperature. It is common for industrial motors to have Class F systems but operate at or near Class B rise at rated load at 1.0 service factor. 21 Phase (PH.) Phase is the indication of the type of power supply for which the motor is designed. The two main categories are single phase and three phase. Single phase means that only one voltage waveform is applied to the motor, while three-phase motors have three wires delivering voltage waveforms, each supplying peak voltage and current at different times. A three-phase motor is more efficient and economical, and most large industrial motors and applications rely on three-phase power. 22 Design letter (DES.) The letter indicates the torque/speed characteristics of the motor. The turning force which a motor develops is known as torque. The amount of torque necessary to start a load (starting torque) is usually different from the torque required to keep the load moving (full load torque). Loads that have high breakaway friction or that require extra torque for acceleration should have a motor specified to have high starting torque. NEMA specifies design letters to indicate the torque, slip and starting characteristics of three phase induction motors. Design A: • Maximum five percent slip • High to medium starting current • Normal locked rotor torque • Normal breakdown torque • Suited for a broad variety of applications, such as fans and pumps Design B: • Maximum five percent slip • Low starting current • High locked rotor torque • Normal starting torque • Normal breakdown torque • Suited for a broad variety of applications - common in HVAC application with fans, blowers and pumps Design C: • Maximum five percent slip • Low starting current • High locked rotor torque • Normal breakdown torque • Suited for equipment with high inertia starts, such as positive displacement pumps Design D: • Maximum five to 13 percent slip • Low starting current • Very high locked rotor torque • Suited for equipment with very high inertia starts, such as cranes, hoists, etc. Design letters are not defined for motors larger than 500 Hp at 1800 RPM. It should be noted that the design letters are not applicable to, and typically not indicated for, motors that are designed for variable speed application only and not suitable for across-the-line starting. 23 Rotor inertia Rotor inertia data is typically included for variable speed applications. Inertia is an object’s resistance to a change in speed. In an electromechanical system, both the motor’s rotor and load have inertia, and how similar (or different) their inertias are will affect the performance of the system. The ratio of the load inertia to the rotor inertia is an important aspect of motor sizing.

In this case, rating information for using the motor on 50 Hz sinewave power (typically outside North America). 14 International protection rating (I.P.) Often incorrectly interpreted as the ingress protection rating, international protection rating classifies the degrees of protection provided against the intrusion of solid objects (including body parts like hands and fingers), dust, accidental contact, and water. The IP allows for the ingress of objects into the motor, providing they cannot have any detrimental effect upon its operation. The first digit of the code indicates the level of protection that the enclosure provides against access to hazardous parts and the ingress of solid foreign objects, and the second digit indicates the protection of the equipment inside the enclosure against harmful ingress of liquid 15 Enclosure type (ENCL) The enclosure, or housing/cooling method, for which the motor is designed. The enclosure must protect the windings, bearings and other mechanical parts from moisture, chemicals, mechanical damage and abrasion from grit. NEMA defines the enclosures, but not the abbreviations, which are common throughout the motor industry. There are more than 20 types of enclosures, some common types being: • ODP: Open Drip Proof • TEFC: Totally Enclosed Fan Cooled • TENV: Totally Enclosed Non-Ventilated • TEAO: Totally Enclosed Air Over • TEWD: Totally Enclosed Wash Down • TEBC: Totally Enclosed Blower Cooled • TELC: Totally Enclosed Liquid Cooled • XPFC: Explosion Proof Fan Cooled 16 Rated horsepower (H.P.) Horsepower is an expression of the motor’s mechanical output rating, or its ability to deliver the torque needed for the load at rated speed. This value is based on the motor's full-load torque and fullload speed ratings and is calculated as follows: Horsepower (Hp)=[Motor speed (rev/min) × Torque (lb-ft)]÷5,250] For an electric motor, one horsepower is equivalent to 746 watts of electrical power and is the standard rating in the United States. NEMA defines certain characteristics or ratings of motors down to 1 milli horsepower for certain types of motors, and up to 100,000 Hp for synchronous machines. NEMA defines ratings for polyphase medium induction motors to be from ½ through 500 Hp. If a load's actual horsepower requirement falls between two standard horsepower ratings, the larger size motor should be selected. 17 Power factor (P.F.) Power factor is the measure of a particular motor’s requirements for magnetizing amperage. The formula “watts = amps x volts” must be altered when inductance is introduced to the load to include a new term called power factor. Thus, the new formula for single phase loads becomes “watts = equal amps x volts x power factor”. Power factor is an expression of the ratio of active power (W) to apparent power (VA) expressed as a percentage. 18 Ambient temperature and time rating (RATING) The motor’s rating is the ambient (room) temperature surrounding the motor and the time it can operate at that temperature. The maximum ambient temperature at which a motor can operate is sometimes indicated on the nameplate. If it is not indicated, the maximum is 40°C for IE2 motors and normally 60°C for IE3 motors. The motor can run and still be within the tolerance of the insulation class at the maximum rated temperature. Most motors are rated for continuous duty (CONT). NEMA considers 40°C to be the default maximum ambient, and continuous to be the default time rating at the rated load. Motors designed for other temperature and time ratings should be by agreement between the manufacturer and the user. 19 Amps at stated volts It is common to include amps at stated volts on smaller motors in the United States. 208 volts (V) is a common supply voltage for some applications in the United States, however, it is common for a manufacturer to indicate the expected current at 208 V as an “alternate” voltage rather than stock different products with 208 V as the primary rating.

horsepower indicated by multiplying the rated horsepower by the service factor. For example, a motor with a 1.0 service factor cannot be expected to handle more than its nameplate horsepower on a continuous basis. A motor with a 1.15 service factor can be expected to safely handle infrequent loads up to 15 percent past its rated horsepower, i.e. a 10 Hp motor could run at 11.5 Hp.The downside is this could create a hotter motor with a shortened expected life. NEMA MG1 9.15.1 States: “An induction motor operated at any service factor greater than 1.0 will have a reduced life expectancy compared to operating at its rated nameplate horsepower.” When operated at service factor load, the motor may have an efficiency, power factor and speed slightly different from those shown on the nameplate. Service factor can also be used to determine if a motor can be operated continuously at altitudes higher than 3,300 feet satisfactorily. At altitudes greater than 3,300 feet, the lower density of air reduces the motor's cooling ability thereby causing the temperature of the motor to be higher. This higher temperature is compensated for by reducing the effective service factor to 1.0 on motors nameplated with a 1.15 service factor or greater. If the motor is operated outdoors at higher altitudes. it's sometimes possible to use full horsepower and full service factor since ambient temperatures are usually lower at those altitudes. 09 Efficiency (NEMA NOM. EFF.) Efficiency is the percentage of the input power that is converted to work output from the motor shaft. In its simplest form, efficiency is calculated by dividing the motor’s output power by its input power multiplied by 100. In actual practice, in three-phase induction motors for example, the industry standards prescribe procedures to determine the various types of losses in the motor and then sum them to determine the net losses. (The difference is very small, but the purpose of the procedure is to ensure that every manufacturer determines and reports the efficiency in a consistent manner.) The higher the percentage, the more efficiently the motor converts incoming electrical power to mechanical horsepower. Efficiency is guaranteed by the manufacturer to be within a certain tolerance band, which varies depending on the design standard, i.e. IEC or NEMA. Unused energy is converted to heat in the motor. The user pays for the energy that goes into the motor but only gets benefit from the output of the motor. The difference -the losses - are consumed and paid for with no benefit received. Energy efficiency is always important since the losses are paid for whenever the motor is running. Energy efficiency is particularly important if power costs are high or if the motor operates for long periods of time. 10 Bearings (DE and ODE) Information is usually given for both the drive-end (DE) bearing and the bearing opposite the drive end (ODE). The difference between these two is the location in the motor. The drive end bearing is located close to where the drive shaft extends out of the motor. The opposite drive shaft bearing is on the opposite side of the drive shaft. The numbers indicate the bearing type and size. 11 Certified compliant number (CC)This number is specific to the manufacturer and appears on all electric motors that comply with the NEMA Premium efficiency specification. Buying NEMA Premium labeled electric motors will help purchasers optimize their motor systems’ efficiency, reduce electrical power consumption and costs and improve system reliability. 12 Serial number (SN) A unique identifier assigned incrementally or sequentially to a motor to identify it specifically. For Baldor-Reliance NEMA motors, the serial number formula is a location-year-month-day-motor code. 13 Alternate ratings or additional application data.

Required or optional information for all NEMA motor nameplates 01 Manufacturer 02 Hazardous location classes and groups 03 Frame size 04 Rated voltage 05 Rated full-load amps 06 Rated full-load speed 07 Frequency 08 Service factor 09 Efficiency 10 Bearings (DE and ODE) 11 Certified compliant number 12 Serial number 13 Alternate ratings or additional application data 14 International protection rating 15 Enclosure type 16 Rated horsepower 17 Power factor 18 Ambient temperature and time rating 19 Amps at stated volts 20 Insulation class 21 Phase 22 Design letter 23 Rotor inertia 24 T code 25 Safety and/or efficiency certification marks Information specific to BaldorReliance NEMA 26 Catalog number 27 Spec number 28 Magnetizing current 29 Inverter type and variable speed range(s) Nameplate information required or optional for all NEMA motors 01 Manufacturer There is no defined design for this field, and it may differ from one manufacturer to the next. In addition to the name of the manufacturer, it can include the motor model, electrical style or the purpose. Here we have a Baldor-Reliance Severe Duty XT motor. 02 Hazardous location classes and groupsKey information is required to accurately specify an electric motor for use in hazardous environments, those areas where fire or explosion hazards may exist due to the presence of flammable, combustible or ignitable substances. These locations are broken down into classes and groups based on the autoignition temperature of the hazardous material and are shown in the table below 03 Frame size (FRAME) Motor dimension standardization is indicated by the frame size. This number reflects the same mounting and shaft information between different manufacturers in order to be consistent. Since NEMA frame size refers to mounting interfaces only, it has no direct bearing on the motor body diameter. 04 Rated voltage (VOLTS) This data indicates the voltage at which the motor is designed to operate most efficiently; however, a motor can still operate effectively at plus or minus a 10 percent tolerance of this value. For example, a motor with a 460V rating could operate effectively at around 414V to 506V. The nameplate-defined parameters for the motor - such as power factor, efficiency, torque and current - are at rated voltage and frequency. When the motor is used at other voltages than the voltage indicated on the nameplate, its performance will be affected. 05 Rated full-load amps (F.L. AMPS) Full-load amps represents the amount of current the motor is designed to draw at the rated load and rated voltage. Motors with a lower F.L.A. with the same amount of horsepower are considered more efficient to operate. 06 Rated full load speed (R.P.M.) The rated full load speed is the speed at which full load torque is delivered for the rated voltage and frequency. The difference between the full load speed and the synchronous speed is called slip. The motor’s slip is determined by its design. For most induction motors, generally, the full load speed can be between 96 percent and 99 percent of the synchronous speed. 07 Frequency (HZ) Hertz is measured in cycles per second. This is the frequency of input power for which the motor is designed to operate at the rated output power, voltage and speed. To operate successfully, the motor frequency must match the power system (supply) frequency. If more than one frequency is marked on the nameplate, then other parameters that will differ at different input frequencies have to be indicated on the nameplate as well. The most commonly occurring frequency in the United States is 60 Hertz, and the most common frequency for motors used outside the United States is 50 Hertz. 08 Service factor (SER. F. or S.F.) The service factor shown on the motor nameplate indicates the amount of continuous overload the motor can be expected to handle, under nameplate conditions, without overheating or damaging the motor. When the voltage and frequency are at the same value as shown on the motor nameplate, the motor may be overloaded up to the

ما هي حمايه ال Pole Discrepancy والتي تعرف ب 52Pd ؟ - في البداية علينا معرفه هذه الحماية تفعل عندما يكون المفتاح المستخدم مع دائرة نقل القدرة او المحول من نوع ال Single Pole وهذا يعنى ان كل من الفاز R والفاز S والفاز T لديها غرفه اطفاء شراره منفصله وميكانزيم منفصل وتستخدم هذه المفاتيح فى الجهود الفائقة مثل 380 ك.ف و ال 500 ك.ف - وبما ان لديهم ميكانزيم منفصل فهناك احتماليه عند ارسال امر التوصيل او الفصل للمفتاح (Circuit Breaker) ان تستجيب للأمر الفازات( R-T ) على سبيل المثال ولا تستجب الفاز (S) - تحدث هذه الحالة بسبب مشكله ميكانيكيه في الميكانزيم الخاص بالمفتاح (Mechanical Stuck) او نتيجة مشكله فى wiring الخاص بدائرة الفصل او التوصيل - يتم التغلب على هذه الحالة التي تعرف باسم pole Discrepancy بأرسال أمر فصل للفازات التي حدث لها توصيل فى مده لا تزيد عن 100 ميلي ثانيه. - يتم تصميم هذه الدائرة من خلال مجموعه من النقاط (NO - NC) لكل فازه كما هو موضح بالصورة - فنجد اذا حدث Pole Discrepancy على أي فاز فأن Timer يعمل مباشره وينتظر الزمن المضبوط عليه ويرسل بعد ذلك أمر فصل لجميع الفازات. - ويتم ارسال أمر الفصل من مسار مختلف عن المسار الخاص بأجهزة Protection - توجد فلسفات مختلفة ل Pole Discrepancy فنجد انه مع محطات ال One and Half يتكون ال Pole Discrepancy من مرحلتين :- 1- المرحلة الاولى ارسال امر ال Trip للفازات التي حدث لها توصيل 2- في حاله عدم استجابة الفازات للفصل سنبدأ في المرحلة الثانية وهو أخلاء Bus Bar الذى يعمل عليه المفتاح وايضا ارسال امر ال Trip لمحطه ال Remote End .

Scheme verification test: 1.OBJECTIVE: To conduct functional verification of scheme of the protection, control and monitoring system as per the schematic drawing. 2. TEST INSTRUMENTS REQUIRED: - Multimeter - Others (if required any). 3. PROCEDURE: Following precautions / status conformation should be taken before starting the testing. - Ensure that items and installation conform to the specified requirements and applicable drawings. - Items are free from damage, have been tested and adjusted as per manufacturer instructions individually. - Available drawings are the as-manufactured status. - All labels and markings are correct. - Ensure free movement of mobile parts. - Correct polarities and continuities of electric circuits. - Auxiliary control voltages are available in correct magnitude and polarities. - Ensure the unit under test is not functionally connected with other live system (i.e.) isolation of trip links, CT isolation of Bus bar protection & etc. Start checking the scheme of each assembly/unit as per schematic diagrams. During this test each device shall be tested for its function verification as a part of overall scheme. Any non-conformity found shall be rectified and recorded. Following shall be verified: - Operation sequence and interlock verification. - Opening and closing operations of switching devices from local and remote. - Tripping of switching devices from protection. - Status of switching devices to local and remote. - Alarms/indications availability to local and remote. Functionality of each unit match / with in the customer stipulated specifications / procedure.

GIS Circuit breaker and gaz density switch https://www.facebook.com/share/r/ZXRPfFsFFwfX6rvy/?mibextid=gYSGZt #electrician #GIS #circuitbreaker

High speed earthing switch GIS https://www.facebook.com/share/r/ETfzaUhKWFctrbbq/?mibextid=7J6EjN

Electrical fuse https://www.facebook.com/share/p/kD3UfRP8nAB46D9r/?mibextid=oFDknk

A capacitor bank is an electrical panel, made of an enclosure, The main breaker MCCB (isolator for protection) Capacitors Contactors Protection fuses Reactors (recommended) Regulator that controls the capacitor bank steps. https://www.facebook.com/share/r/Pu2iRQUjNTUtspYe/?mibextid=oFDknk

Chloride DC UPS The Chloride industrial rectifier is the result of engineering research in product simplification to offer an SCR based standardized design with adaptability to industrial requirements. It is suitable for use either as a rectifier, as a battery charger or as a DC power supply. #electrician #electronics #DC https://www.facebook.com/share/r/6rBUFxgUR5pfZSbb/?mibextid=oFDknk

Micom p127 alarm reset https://www.facebook.com/share/r/NmE4ZvjXbZU1EcXB/?mibextid=oFDknk

The use of impedances in the electrical network (Shunt Reactors): When electrical energy transmission methods were used, it was noted that if the voltage is sent by, for example, 100 kV, it reaches the arrival point with a higher value than that sent, it may reach a value of 110 kV or more, and the percentage of increase in voltage changes depending on the length of the line, the value of the transmitted voltage and several other factors. And this increase in the value of the voltage is not a random increase, but to understand it simply, let's remember together what is the idea of the work of the Capacitor capacitor, it is two conductors with two different voltages and between them is an insulator, and the Capacitor charges and discharges with each cycle of electric current and as we know that the earth is a conductor with zero voltage and the transmission line has a voltage of a value and the air is a dielectric between the earth and the line and therefore we have a capacitor along the line that charges and discharges and this discharge is the one that It increases in voltage and that is why the voltage increases when reaching higher than the voltage when transmitting. But the value of the voltage designed at the electrical equipment and the maximum value allowed to increase it must be taken into account in a way that does not affect the efficiency of the electrical network, so it is not correct to design the network, for example, at a voltage of 400 kV and send the voltage at a value of 400 kV, but the voltage reaches a value of 450 kV, for example. Therefore, we need to compensate for the value of the unrequired increase in voltage. Therefore, we need to reverse the value that is added by the formation of capacitance along the line. The theory of the action of the reactor impedance is the opposite of the theory of the work of the capacitor, where the impedance consists of a coil that can be connected in series or in parallel, and in this case it must be connected in parallel with the Shunt reactor line, so if we add the reactor with a value that reduces the voltage equivalent to the value that the capacitor increases along the line, we can maintain the voltage between the transmitter and the receiver. Where the Reactor can be connected in more than one way, for example, it can be connected with the busbar directly through the circuit braker, and in the event that the line is very long and an increase in voltage may occur with a high value, for example, if the transmitted voltage is 400 and will reach a value of 450 kV, for example, this value must be equalized before connecting the line from the other side with the network, so Reactor must be added to the line directly before connecting with the network.

SURGE ARRESTOR • SURGE ARRESTOR are devices used to provide thenecessary path to ground for such surges, yet prevent anypower current from following the surge. An ideal arrestermust therefore have the following properties: 1. Ability to remove the surge energy from the line in a min. time. 2. High resistive to flow of power current. 3. A valve action automatically allowing surge to pass and then closing up so as not to permit power current to flow to ground. 4. Always ready to perform. 5. Performance such that no system disturbances are introduced by its operation. 6. Economically feasible

Medium and High Voltage Circuit Breaker: What the protection engineer needs to know •Frame size •For 15kV switchgear this is typically 600A, 1200A, 2000A, 3000A •Interrupting rating in kA symmetrical RMS •Typical values @15kV are 25kA, 31.5kA, 40kA, 50kA, 63kA •Interrupting time •Typical 3 or 5 cycles @60hz •Short time withstand •Typically, 2 seconds for ANSI switchgear •Various Ratio and class of current transformers available •Trip coil voltage •DC – 24V, 48V, 125V, 250V •AC – 120V, 240V (needs capacitor trip) •Note trip coil voltage and circuit breaker control voltage may not be the same

What on afford nako back nako all

TAN Δ, OR TAN DELTA Tan Delta, also called Loss Angle or Dissipation Factor, is a diagnostic method of testing cables to determine the quality of the cable insulation. This is done to try to predict the remaining life expectancy and in order to prioritize scheduled maintenance, replacement, or rejuvenation of the cable system under test. HOW DOES IT WORK? If the insulation of a cable is free from defects, like water trees, electrical trees, moisture and air pockets, etc., the cable approaches the properties of a perfect capacitor. It is very similar to a parallel plate capacitor with the conductor and the neutral being the two plates separated by the insulation material. In a perfect capacitor, there is a phase shift between the current and voltage, where the current leads the voltage by 90 degrees and the current through the insulation is capacitive. If there are impurities in the insulation, like those mentioned above, the resistance of the insulation decreases, resulting in an increase in resistive current through the insulation. It is no longer a perfect capacitor and the phase shift between the current and voltage will be less than 90 degrees. The extent to which the phase shift is less than 90 degrees is indicative of the level of insulation contamination, hence quality/reliability. This “Loss Angle” is measured and analyzed. Below is a representation of a cable. The tangent of the angle δ is measured. This will indicate the level of resistance in the insulation. By measuring IR/IC, we can determine the condition of the cable insulation. In a perfect cable, the angle would be nearly zero. An increasing angle indicates an increase in the resistive current through the insulation, meaning contamination. The greater the loss angle, the greater the degradation in the cable. WATER TREES? Water trees are small tree shaped channels found within the insulation of a cable, caused by the presence of moisture. They are very prevalent in service aged XLPE and other solid dielectric insulations, like PE and EPR type cables. These tree shaped moisture channels, in the presence of an electrical field, eventually lead to the inception of partial discharge (pd), which eventually leads to the formation of electrical trees, which grow to a point where insulation failure occurs. The tan delta test shows the extent of water tree damage in a cable. HARDWARE NECESSARY The TD-65E tan delta transducer analyzes the voltage and current waveforms and calculates the tan delta number. A wirelessly connected laptop computer can be used to display and store the results. A voltage source is needed to energize the cable. In this case, a Very Low Frequency (VLF) AC Hipot. The VLF-34E pictured here is a 34 kV (peak) unit that is capable of testing from 0.5µƒ of cable load at 0.1 Hz, up to 5.0 µƒ at 0.01 Hz. VLF hipots are also widely used for testing newly installed and/or repaired cable before reenergizing to insure the cable is sound and for testing critical cable runs.