Current transformer is an important secondary equipment in power system. It is widely used in measurement, measurement, relay protection and other secondary circuits. In the case of high current or high voltage, we can not directly measure the current of the circuit with a galvanometer, only through the secondary side of the current transformer. We learn in this video, what is meaning of 5P10 ,0.2,0.2S class in current transformer are high, classes 5P10 or 10P10 may not be adequate. In these situations a Class PX current transformer will usually be specified. Class PX as defined in IEC60044-1/BS EN60044-1 allows the manufacturer of a protection device to detail more specific current transformer
. The 5 is the % error when the factor of CT rated current flows. The 10 is factor up to where the CT remain accurate within the error limit A current transformer could comply with requirements of several combinations, e.g. 30 VA, 5P10 and 15 VA, 5P20. For metering the ANSI/IEEE specification of the current transformer could be 500/5A, 0.3 B0.5 (, 60 Hz). In that case, the burden will be 0.5 x 5² = 12.5 VA Current Transformers range from Rayleigh Instruments Limited. Our extensive range of single phase current transformers includes moulded case and protection transformers. IME TAWC TAS125P Single Phase Protection Class 5P5 5P10 5P15 5P20 Current Trans... Protection current transformer (formerly TAS125P) Ranges: 400 to 4000A (1A or 5A.
The CT accuracy class for 5P10 transformers per IEC Std 60185 is as follow: 5 = max. permissible total error, P= stand for protection and 10= Accuracy limit factor (ALF). I am not familiar with the other two accuracy nomenclatures (10B50 and 0.5M5) • Ring type current transformer, protection class. • Tough resilient flame retardant. • Temperature range -20°C to 70°C ,br> • Protection class 5P5, 5P10, 5P20 etc. • Test voltage 4Kv 50Hz. 1min. • IEC60044-1, IEC61869-2, IEC185, BS3938, DIN42600 • Tropicalised design with Insulation Class A and thermal 105°
In addition the classification of protection current transformers indicates accuracy class: 5P - current transformer will have a ratio error of 1% and phase error not exceeding 60 minutes. 10P - current transformer will have a ratio error of 3% (no level of phase error specified) The most commonly used protection class is a 5PX, where X is the accuracy limit factor (ALF) or multiplication factor of the rated primary current. The secondary current is +/-1% accurate at rated primary current and +/-5% accurate at X times rated primary current. Typical protection class CT ratings are 5P10, 5P15, 5P20
A current transformer with a wrong burden rating or a wrong accuracy class will seriously compromise the effectiveness of the measuring or protection system. Calculating the burden of a Current Transformer. The burden of a current transformer is indicated in its nameplate. The burden is rated in VA. such as 15VA or 25 VA . Current1 transformers with a lower precision class lead in the complete system - current transformer + measuring device - to a lower accuracy of measur3ement, which is defined in this case by the precision class of the current tran4sformer PS-Class [Special Purpose] Current Transformers: Class PS transformers are the special purpose protective current transformers. These are used where the required characteristics of the current transformers cannot be conveniently expressed in terms of the ordinary protection current transformers like Class 5P, 10P and 15P current transformers The protection class CT has more knee point voltage than the metering class CT. The protection class CT is more bulky because it has more core material. The fault current can be 10 times or 20 times more than the rated primary current of CT. 5 P20 CT means the CT will not saturate if the 20 times more current of the CT rated current flows. Current transformers Principle of operation of CT. A current transformer is defined as as an instrument transformer in which the secondary current is substantially proportional to the primary current (under normal conditions of operation) and differs in phase from it by an angle which is approximately zero for an appropriate direction of the connections
The high quality Current Transformer available with us; is a measuring device used in metering & protection system. The Bar Primary ring-type current transformers consist of a secondary coil wounded on a torroidal core, if high permeability silicon steel is used in production The purpose of a protection class current transformer is measure current during the fault condition and give input to the relay.Based on the current input, the relay then decides for the actuation of trip signal to Circuit Breaker to isolate the healthy section of power system from the faulty section. This simply means that, the main requirement for a protection class CT is that it should. the CT will sense the current with the specified accuracy even with 20 times of its secondary current flows in the secondary. This is required for protection CT, because the fault current is high and the CT should be able to sense the high fault current accurately to protect the system. The common numbers are 10, 15, 20 and 30. Class PS The current transformer has a rated primary current of 300 A and a secondary rated current of 5 A. The burden of the current transformer is 5 VA and its precision is according to class 1. The CM-CT 300/5 will be delivered with foot angle, insulating protective cap and bar fastening screws. A snap-on mounting for DIN rail is avaiable as accessory
Electric Equipment Three Phase Current Transformer 5p10 , Find Complete Details about Electric Equipment Three Phase Current Transformer 5p10,Current Transformer 5p10,Three Phase Current Transformer,Electric Equipment from Other Electrical Equipment Supplier or Manufacturer-Beijing Richang-Science Instrument Transformer Equipment Co., Ltd Class : Measuring CTs : 0.5, 1, 3 Protection CTs : 5P, 10P Short time thermal current : Ith = 60In Epoxy Resin Coating Current Transformer 5P5 5P10 5P5 5P10 5P5 5P10 60/5A 35 85 50 _ _ _ _ _ _ 100/5A 35 75 30 38 38 120 120 115 130 150/5A 35 70 30 38 38 110 110 95 105 200/5A 35 65 30 38 38 100 100 90 105 250/5A 35 65 30 38 38 95 95 90 105.
LOW TENSION CURRENT TRANSFORMERS Rated Burden :- 15 VA , Accuracy Class :- 5P10 Approximate Dimensions in mm Ratio ID (mm) OD (mm) Ht.(mm) Price (Rs.) 100/5 A 30 160 160 6900.00 150/5 A 30 130 140 4100.00 200/5 A 50 150 125 3500.00 250/5 A 50 145 125 3500.0 PREFERRED CURRENT TRANSFORMERS, 50 Hz Commercial code Rated primary current Short-circuit strength Core S1 Core S2 12 kV 12 24 kV 24 Short-time current, 1 s Surge current Class 0.5 F s R ct Ω 5P10 R ct Ω U k I o m [A] [kA] r.m.s. [kA] peak VA 50-100 50-100 11-22 20-40 30-60 50-100 15 5 5 15 0.16 0.04 15 5 0.07 0.03 25.0 12.0 145 290 KOFA _ D2. In IEC, the current transformer class of interest to this discussion is the class P protective current transformer. The rated output classes in IEC are 5, 10, 15, 20, and 30, where the number represents the load output in VA at rated secondary current. The preferred accuracy classes are 5P (5 percent maximum error) and 10P (10 percent maximum. . This fact will be more evident if you look at the accuracy class of protection class CT. It is generally 5P10 or 5P20 The current transformer has a rated primary current of 600 A and a secondary rated current of 5 A. The burden of the current transformer is 5 VA and its precision is according to class 1. The CM-CT 600/5 will be delivered with foot angle, insulating protective cap and bar fastening screws. A snap-on mounting for DIN rail is avaiable as accessory
We supplies all types of PROTECTION CLASS CURRENT TRANSFORMERS encapsulated with UL94V-0 with Polycarbonate. We are providing following Class: 5P5 10P5 5P10 10P10 According to customer requirement we have different ranges based on Current Rating, Busbar Size, Case Width,Cable, Bus Bar and DIN Rail Mounting.. Current transformers, along with voltage or potential transformers, are instrument transformers.Instrument transformers scale the large values of voltage or current to small, standardized values that are easy to handle for measuring instruments and protective relays.The instrument transformers isolate measurement or protection circuits from the high voltage of the primary system ABB Current Transformer. Example of a CT specification: - a very common specification for a protection class CT would be an accuracy class 5P (1%), with rated accuracy limiting factors of 10 or 20. Typical burdens would be 5, 10, 15 or 20 VA. A typical specification would be 5P10 15 VA. The IEC 60044 Metho
The impedance of the measuring circuit being driven by the current transformer produces some voltage at the transformer. The product of the current and voltage should not exceed the VA rating. The meaning of Class depends on how it is defined in some specification for a group of current transformers founding of MH Current Transformer is to in line with Mun Hean's flagship product, MH Protection Relays and Meters. On 1994, the product range for Protection Current Transformer is extended to Class X Type and subsequently in year 1996, Class 0.5 Metering Current Transformer is included in the production range. The complete chai LZCG530-10 Zero Phase Current Transformer, Ring net cabinet 5P10 Ratio 100A / 1A Zero Sequence Current Transformer 100A Zero Phase Current Transformer The 200A zero phase current transformer can endure input current ranging from 50A to 100A
Resin Cast WPL Type L.T. Resin Cast Current Transformer . Resin Cast Wound Primary Type L.T. Resin Cast Current 5P10, 5P20, 10P10, 10P20: Special Protection (PS) Instrument Security Factor (ISF): 2.5, 5, 10: Thermal Insulation Class: Class A, Class B &Class F: Type / Encapsulation: Resin Cast, Moulded Case & Tape Insulated: Construction. Current Transformer PS Class. Before understanding Knee Point Voltage of Current Transformer and current transformer PS class we should recall the terms instrument security factor of CT and accuracy limit factor.. Instrument Security Factor or ISF of Current Transformer. Instrument security factor is the ratio of instrument limit primary current to the rated primary current LZCK322 - 10 45mm diameter 100A/1A 5P10 Cast Resin Zero Sequence Current Transformer with IEC 61869-2 is suitable for current measurement and microcomputer protection of electrical equipment in 10KV and 35KV AC power system. The current transformer can be directly installed at the inlet andoutlet cables.The slice is imported silicon material Class 5P10 is already answered in the earlier thread. These are generally used in General Protection applications which involves current based protection circuits like overcurrent, reverse power etc... Class PS is an abbreviatioin for Protection-Special Class of CT's. These are used generally for Differential Protection application
GFLZZ0757-35Q Epoxy Resin Medium Voltage outdoor Current Transformer. The supporting-type current instrument transformers GFLZZ0757-35Q are fully enclosed and cast in epoxy resin. Transformer is equipped with one core and coil assembly rated for measurement and protection. The transformers are designed for electric power systems of 50Hz/60Hz. Relcotech Transformer Manufacturer Sdn Bhd - Current Transformer, Relcotech Transformer Manufacturer Sdn Bhd is your premier source for the best transformer manufacturers & lighting supplier in the power source industry. Class 5P10 15VA. Class 10P5 15VA. Class 10P10 15VA. Class3 5VA. Class1 15VA. Class 5P10 15VA. Class 10P5 15VA. Class.
Low Voltage Current Transformer RCT 25. Class 5P10 15VA. Class 10P5 15V The ESBM 106-54-82 is a low voltage current transformer for mounting around the bushing/conus connector in switchgear applications. Due to its optimized design it fits around almost all bushing connectors. These current transformers are supplied with a declaration of conformity
Jual CT (Current Transformer) Ring 2500/5A Class 5P10 30VA dengan harga Rp852.000 dari toko online CV Galaxi Mega Electric, Kota Surabaya. Cari produk Komponen Listrik lainnya di Tokopedia. Jual beli online aman dan nyaman hanya di Tokopedia A current transformer is a transformer, which produces in its secondary winding a current, which is proportional to the current 15VA Class 5P10 Class X CTs Class X CTs are special CTs used mainly in balanced protection systems (including restricted earth fault) where the system i China 50/5A 5p10 Three Phase Protection Current Transformer with 15va Burden, Find details about China Protection Current Transformer, 5p10 Protection Current Transformer from 50/5A 5p10 Three Phase Protection Current Transformer with 15va Burden - Beijing GFUVE Electronics Co., Ltd For example: 1600/5, 15VA 5P10. Selection of Accuracy Class & Limit Factor. General: Class 5P and 10P protective current transformers are generally used in overcurrent and unrestricted earth leakage protection
Indoor Current Transformer offered can be made available by us in different operating configuration choices so as to provide for best match as per the specific working needs of the customers. Further, the use of quality component support also makes these provide for reliable performance. Some of its features include 11KV Single Phase (PT) Indoor Voltage Transformers; coming with built in H.V. The SES range of PVC tape insulated Protection CTs are designed and manufactured to cater for wide range of applications. They are tested to IEC 60044-1 2003-02 and are certified to ASTA and CE mark Certified to UL Wound Current Transformer- The transformers primary winding is physically connected in series with the conductor that carries the measured current flowing in the circuit. The magnitude of the secondary current is dependent on the turn ratio of the transformer. Class 1 or 3 - for ammeters, Class 5P10 or 5P20 - for protection, KNEE. Epoxy or Polyurethane Resin Moulded Wound Primary Type; For Indoor Measuring/Protection Use; Highest System Voltage : 0.72KV, 3.6KV, 7.2KV, 12KV; Rated Primary Current: 5A-1200
Here 5VA is the maximum limit of the current transformer's output. These data are used to protect the Current transformer from overloading. The 5VA/5VA means both the core can be loaded upto 5 Volt Amp. Class: PS 5p10, 0. Current Transformers We are recognized as a successful manufacturers, exporters and traders of Current Transformers - CT. It is a static machine used for transforming power from one circuit to another without changing frequency. it is generally used in transmission network which is normally known as power transformer, distribution transformer is used in distribution network and this is lower. 5P10 class CT: P stands for protection class. If the primary current is 10 times to the rated primary current of the CT, the CT will function perfectly, within the rated composite accuracy class 5 %. 5P20 class CT: P stands for protection class RISH Protection class CTs. Rish Protection class CTs are square & round type encapsulated with UL94V-0 approved polycarbonate.These CTs used for protection purpose (acc class 5P10, 10P10 etc)& features wide range of primary current ratings, Busbar sizes,case widths,having wall, cable, bus bar & DIN rail mounting
EPOXY PROTECTION CURRENT TRANSFORMER lOPlO Mnrlal Rat in R~~rrlan Class IDlAI ODfBIAII in mm HTICI EPOXY PROTECTION CURRENT TRANSFORMER 10P; EPR 1 10015A 1 5VA 1 5P20 I 34 150 I 120 Model Ratio Burden Class - ID(A) OD(B)AII in mm HT(C) - EPR I 15015A I 5VA I 5P20 I 34 150 1 95 EPR I 20015A I 5VA I 5P20 I 45 160 ( 7 LZZBJ9-10C(1，2，5) current transformer: Description and meaning of model. LAABJ9-10C type current transformer is epoxy resin cast indoor total working conditions of the strut.Protection or energy measurment with the power system with rated frequency 50Hz rated voltage of 10kV and below.Which LZZBJ9-10C mounted in switch cabinets or other types of switchgear PS class means protectionclass CT. 5P10 means 5% errorshown while 10 times fault current flows.and 5P20 5% errorshown while 20 times fault current flowshence 5P20 superior comparing to 5P10 Din-Rail Enclosure 3-in-1 Current Transformers.....21 Dual Load 3-in-1 Current Transformers.....22 Q2C 3-in-1 Current Transformers..... 23 IV. Moulded Current Transformers Ebony Current Transformers 26-35 CS Range 36-39 AS Range 40-43 RS Range 44
Rated Primary Current 10 to 600 A Rated Short Up to 25kA/1s Thermal Current (lth) Depend on Rated Primary Current, Accuracy Class and Burden Accuracy Class 0.2S - 0.2 - 0.5S - 0.5 5P10; 5P20 Rated Burden up to 30 VA FA catalog CTVT.indd 6 9/30/13 9:33 P protection secondary class is 5P10. Class 5P10 means that the current transforming ratio up to a minimum of 10 times the rated primary current (300 A) is achieved when an excessive current flows from the primary at any fault of the transformer , . When a current of 10 times o purpose (acc class 5P10, 10P10 etc)& features wide range of primary current ratings, Busbar sizes,case widths,having wall, cable, bus bar & DIN rail mountings. Special Features : Comprehensive measurement of class accuracy. Cost effective moulded case current transformer. Wide range of system current ratings, bus bar sizes, case widths and. Current Transformers Features and Benefits The AS series of moulded case current transformers offers a wide range of current ratings, apertures and case sizes to suit every application. The range benefits include ratio ratings from 10A to 5000A, accuracy up to class 0.5. The range is available in both 5A and 1A versions, with an integral termina
Regardless of whether you need a 1a current transformer, 5a current transformer, CT class 5p20 model, or other type of instrument current transformer, we recommend choosing a style first - either solid ring core or oval CT Then, choose a model based on the size of the conductor being measured and the maximum current load you are measuring TQ120 is a very compact split-core current transformer suitable for low voltage systems. The unit is easy to install while the top part can be removed entirely. +31 (0)521 533 33 current transformer & cbct Being a very prominent Current transformer (C.T.) & CBCT manufacturers in Ahmedabad, our current transformers can be operated on low voltage highly energy efficiency for the industries Frame Size Ratio Class 10P10 Class 5P10 Class 10P15 Class 5P15 Class 10P20 Class 5P20 VA VA 2.5 3 4 5 7.5 2.5 5 7.5 10 15 2.5 5 7.5 10 15 2.5 5 7.5 10 15 2.5 5 7.5 10 15 2.5 5 7.5 10 15 2.5 5 7.5 10 15 ENCASED MEASUREMENT CURRENT TRANSFORMERS (CTME Series) Both measurement and protection CTs are available with the encased range PHASE CURRENT TRANSFORMERS for overcurrent protection. GENERAL CHARACTERISTICS; Rated thermal current Insulation class (EN60085) E; Built according to the standards 5P10 55 170 60 3,5; TTA55D35 150 5 5VA 5P20 55 170 35 6; TTA55D35 200 5 1VA 5P15 55 170 35 1,8; TTA55D35 200 5 2,5VA 5P10 55 170 35 2
to testing and shall be commensurate with the accuracy class of the transformer under test. c) Full accuracy routine tests to IEC 61869-2. 3.3.2 Capacitance and dielectric loss angle (tan δ) measurements of the primary insulation over 5P10 Note - For tapped current transformers the knee-point voltage, magnetising current and secondary. Epoxy Resin Current Transformers in Molded Case Fire resistance, Flame retardant UL-94V0 Temperature range 10°C to 70°C Accuracy class 5P10, 5P20. According to IEC60044-1, IEC61869-2, IEC185, BS3938, DIN42600 Tropicalized design with insulation class E and thermal 120° current A Class and burden METERING Class and burden PROTECTION Class and burden METERING Class and burden PROTECTION IFE-1 200 5 VA CL1 2.5 VA 5P10 250 12.5 VA CL1 2.5 VA 5P10 300 5 VA CL0.5 2.5 VA 5P10 400 12.5 VA CL0.5 5 VA 5P10 500 5 VA CL0.2 25 VA CL0.5 5 VA 5P10 2.5 VA 5P15 CURRENT TRANSFORMERS > Metering and protection > Indoor. The rated output classes in IEC are 5, 10, 15, 20, and 30, where the number represents the load output in VA at rated secondary current. The preferred accuracy classes are 5P (5 percent maximum error) and 10P (10 percent maximum error) CURRENT TRANSFORMER RATINGS Rated Burden Value of Burden upon which accuracy claims are based Usually expressed in VA Preferred values :- 2.5, 5, 7.5, 10, 15, 30 VA Continuous Rated Current Usually rated primary current Short Time Rated Current Usually specified for 0.5, 1, 2 or 3 secs No harmful effects Usually specified with the secondary.
Resin Cast Bar Primary Current Transformers Resin Cast Wound Primary/ Encapsulated Current Transformers Polycarbonate casing/Relay Operated/Air Circuit breakers Current Transformers Current Transformer Types. There are four typical types of current transformers: window, bushing, bar, and wound.The primary winding can consist merely of the primary current conductor passing once through an aperture in the current transformer core (window- or bar-type), or it may consist of two or more turns wound on the core together with the secondary winding (wound type) for the shown diagram an internal earth fault has occurred at 40 % of the transformer winding. So, if we neglect the fault impedance then actual earth fault current shall be 40% of 400A i.e. 160A only, & CT secondary current or relay current shall be=160*1/1800=0.088 A. Addition of fault impedance will further reduce fault current
PR Protective Current Transformers. Application: PR Sereis Protective current transformers are required to operate over a range of current many times the circuit rating and is frequently subjected to conditions greatly exceeding those which it would be subjected to as a measuring current transformer Relcotech Transformer Manufacturer Sdn Bhd - Class 5P10 15VA Protective Current Transformer Current Transformer Selangor, Malaysia, Kuala Lumpur (KL), Rawang Manufacturer, Supplier, Supply, Supplies, Relcotech Transformer Manufacturer Sdn Bhd is your premier source for the best transformer manufacturers & lighting supplier in the power source industry. Our main office is located in Rawang.
Explaining the principles of protection current transformers and there applications for engineers and students of electrical engineering. Characterisation of a protective current transformer class is as follows: For example, 1600/5A, 15VA 5P10. Switchgear Protection PROTECTION CURRENT TRANSFORMERS NITECH Protection Current Transformers have been designed to comply with class 5P and 10P with Accuracy Limit Factors (ALF) 5 to 20 times
5P10 & 5P20 Class CTs: They are generally used for Over current (Instantaneous and IDMT relays) and E/F protection of Feeders, Transformers etc. (i) 5 signifies the % limit of composite error Figure 4 - Current transformer in MV switchgear. CT secondary circuit must be grounded, and grounded at one point only.If the secondary of CT is left unloaded a risk of explosion exists.. You may also read: Transformers Fire Protection System - Causes, Types & Requirements Special precautions must be taken when connecting CT primary (connection points are usually identified by P1 and P2.
12kv Epoxy resin cast fully enclosed post type current transformer Technical parameters: TYPE: LZZB9-40.5 INSULATION LEVEL:17.5/38/95kV RATED CURRENT RATIO:1250/5-5A INDOOR USE FREQUENCY: 50-60Hz STANDARD: IEC60044-1 (1S1-1S2) 5P10 CLASS 15VA (2S1-2S2) 5P10 CLASS 15VA 5P10/5P10, 15/15VA LVB35-500kv LVB oil impregnated inverted current transformer SMPS & Current Transformer Wholesale Supplier of a wide range of products which include Core Balance CT (ZCT), Current Transformer, Encapsulated / Tape wound CT, Resin Cast Current Transformer, Clamp on CT 5Amps and Split Core Ct *For close-up, click the above pictures : Epoxy Measuring Current Transformer Class TPS low leakage current transformer performance is defined by the secondary excitation characteristic and turns ratio limits. No limit on remanent flux (IEC 60044-6). III. BURDEN The IEEE standard burdens for relaying are 1, 2, 4, and 8 ohms, all with an impedance angle of 60 degrees. However, th
In the above given data CT is 5P20 with CTR 200/1. The ALF is 20. CT accuracy class is 5. It means if 20 times of the rated primary current(4000 amperes) flows in the primary at the time of fault, the CT reads the current with 5 % accuracy.This factor (In x 20) 20 is called the accuracy limit factor(ALF). If the current in the primary of CT exceeds above 20 times of the primary rated current. Current Transformers We are a prominent manufacturer and exporter of a wide assortment of superior quality Current Transformers for our precious clients. The offered products are made using the best quality raw material and the most-advanced machinery under the supervision of skilled professionals. · Accuracy Class : 5P10 · Core Type. Current transformers for low-voltage network Protection Single-phase current transformer Passing bus bar primary Primary current 400...4000A Secondary current 1 - 5A Accuracy class: cl.5P5 - 5P10 Rated burden 3...50VA SENSORI DI CAMPO SENSORS TAS125 Coprimorsetto sigillabile Sealable terminal cover (Opzione Option ) N T 5 7 5 0 3-2 0 1 8 8 a E.
Transformer TRP100 1500/5A 5P20 Protection current transformers : TRP100 1500/5A 5P20 We use our own and third-party cookies to improve browsing and provide content of interest Instrument transformers are used for measurement and protective application, together with equipment such as meters and relays. Their role in electrical systems is of primary importance as they are a means of stepping down the current or voltage of a system to measurable values, such as 5A or 1A in the case of a current transformers or 110V or 100V in the case of a voltage transformer
Output Current 1A 5A Class 10P10 5P10 1VA 5VA Ring Type Transformer, US $ 88 - 336 / Piece, China, Sihu, LXZK2-120mm.Source from Guangdong Sihui Instrument Transformer Works Co., Ltd. on Alibaba.com Metering current transformers are designed to be within quite accurate values up to say two x rated current, and down to <0.01 x rated. Consequently a protection relay connected to a metering current transformer will get a heavily saturated waveform during fault conditions and it won't work properly. IEC Class P CTs for standard IDMT OC or even distance may only be 10% accuracy - it is.
We are committed to provide first class Electrical Panel Parts Manufacturing Solutions to our clients. Electrical Components Manufacturer Founded in 1979, we embody more than thirty years of experience and excellence in serving clients from all over the world Instrument transformers are high accuracy class electrical devices used to isolate or transform voltage or current levels. The most common usage of instrument transformers is to operate instruments or metering from high voltage or high current circuits, safely isolating secondary control circuitry from the high voltages or currents CT Specs - Part 2 - Class P Application Preamble. Part 1 of this blog presented an overview of Australian & IEC standards for Class P type Current Transformer (CT) specifications. This blog presents the application of Class P type CTs in actual site conditions. This process can be confusing due to the diverse methodology presented in the literature