Question 1

What is the Restricted earth fault protection and how to implement on Low Voltage ?

Accepted Answer

The restricted earth fault protection (ANSI 64REF) can be applied if the downstream power system neutral is earthed at the transformer (document attached).This is a differential protection function that detects the difference between residual currents measured at the neutral earthing point and at the three-phase output of the transformer.Please find attached document describing how to implement the estricted earth fault protection with Masterpact Micrologic 6.0

Question 2

What is the definition of ANSI 64REF - Restricted earth fault differential?

Accepted Answer

Detection of phase-to-earth faults on 3-phase windings with earthed neutral, by comparison of residual current calculated from the 3 phase currents and residual current measured at the neutral point.Characteristics instantaneous trippingpercentage-based characteristic with fixed slope and adjustable low set pointmore sensitive than transformer or machine differential protection.

Question 3

Video: Creating a report subscription to email on an alarm in Power Monitoring Expert

Accepted Answer

Product LinePower Monitoring ExpertEnvironmentEvent Watcher Manager and Web ApplicationsResolutionStep 1. Enter Subscription Email Configuration (SMTP Server, "From" Display Name, "From" Display Address) Launch Management ConsoleEnter username, passwordSelect Tools >> Reporting Configuration >> Reporting Configuration ManagerClick on the Subscriptions TabEnter the SMTP Server IP address, "From" Display Name, and "From" Email AddressPress OK Step 2. Create the Alarm Within Management Console, select Tools >> Reporting Configuration >> Event Watcher ManagerConfigure alarm using Event Watcher Manager Select NewGive the alarm a nameSelect the appropriate template Note: Custom templates can be created using the Template tab. For example a common use case is for Sag/Swell events only, please see FA407306. If desired, give the alarm a descriptionSelect the device(s) that the alarm will apply toPress OK Step 3. Create the report subscription Launch Web applicationEnter username, passwordClick on Reports tabCreate, Run and save the desired report: In the Report Library, Select Report type (or create a new one)Setup the report parametersGenerate the reportClick Save button Select the save location and press OK Create the report subscription: Click on Subscribe Customize the subscription nameSelect an output format of email Click Distribution listEnter the email address of each desired recipientOptional: Enter a subject for the email Under subscription schedule, select On AlarmSet deliver report on alarm to the alarm created in Step (1)Optional: You can click on to test the alarm.Click Save For How to set up a Comms Loss alarm through Event Watcher and send alert in form of a report subscription in ION Enterprise, SPM 7, or PME7.xx, please see FA275287.

Question 4

What is the definition of ANSI 67N/67NC - Directional earth fault?

Accepted Answer

Earth fault protection, with selective tripping according to fault current direction.3 types of operation: type 1: the protection function uses the projection of the I0 vectortype 2: the protection function uses the I0 vector magnitude with half-plane tripping zonetype 3: the protection function uses the I0 vector magnitude with angular sector tripping zone ANSI 67N/67NC type 1 Directional earth fault protection for impedant, isolated or compensated neutral systems, based on the projection of measured residual currentANSI 67N/67NC type 2 Directional overcurrent protection for impedance and solidly earthed systems, based on measured or calculated residual current.It comprises an earth fault function associated with direction detection, and picks up if the earth fault function in the chosen direction (line or busbar) is activated.ANSI 67N/67NC type 3 Directional overcurrent protection for distribution networks in which the neutral earthing system varies according to the operating mode, based on measured residual current.It comprises an earth fault function associated with direction detection (angular sector tripping zone defined by 2 adjustable angles), and picks up if the earth fault function in the chosen direction (line or busbar) is activated.This protection function complies with the CEI 0-16 Italian specification.

Question 5

What is the definition of ANSI 46 - Negative sequence / unbalance?

Accepted Answer

Protection against phase unbalance, detected by the measurement of negative sequence current: sensitive protection to detect 2-phase faults at the ends of long linesprotection of equipment against temperature build-up, caused by an unbalanced power supply, phase inversion or loss of phase, and against phase current unbalance.

Question 6

What is the definition of ANSI 50V/51V - Voltage-restrained overcurrent?

Accepted Answer

Phase-to-phase short-circuit protection, for generators.The current tripping set point is voltage-adjusted in order to be sensitive to faults close to the generator which cause voltage drops and lowers the short-circuit current.

Question 7

Where can I find the UL certificates for Compact NSX MCCBs, Compact NS MCCBs and Masterpact ACBs?

Accepted Answer

The answer will be provided in an orderly manner, first Compact NSX MCCBs, then Compact NS MCCBs and finally Masterpact ACBs.1. The Compact NSX breakers are UL listed according to UL508 for Manual Motor Controllers in file E186495. The correct term when dealing with UL is "listed", not "certified". Now concerning UL489, it is rather a separate offer called Powerpact with Micrologic from Square D in US market. Please find the Compact NSX UL508 as well as the Powerpact UL489 certificate of compliances attached (refer to CoC UL508.pdf, Powerpact H and J - UL489 Certificate of Compliance.pdf and Powerpact L - UL489 Certificate of Compliance.pdf). This covers the entire spectrum of currents up to 630A. You can also check the UL Listed file on the Internation UL database via the following link: http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/showpage.html?name=NLRV.E186495&ccnshorttitle=Motor+Controllers,+Manual&objid=1074107674&cfgid=1073741824&version=versionless&parent_id=1073990270&sequence=12. The Compact NS630b-1600 range MCCBs are not UL listed. If you need UL listed Compact NS >630A circuit breakers, you have to opt-to the Power pact M-frame, P-frame and R-frame ranges by Schneider Electric USA (Square D). Attached are the relevant UL Certificates for the same (Powerpact M - UL489 Certificate of Compliance.pdf, Powerpact P - UL489 Certificate of Compliance.pdf and Powerpact R - UL489 Certificate of Compliance.pdf) 3. The Masterpact ACBs are UL489 and UL1066 listed as illustrated in the relevant two documents (refer to Masterpact NW - UL1066 Certificate of Compliance.pdf and Masterpact NW - UL489 Certificate of Compliance.pdf). Please note that the UL489 version is different than the UL1066/ANSI version. They are not a single multi-standard product.You will find all the above mentioned documents in one attached compressed file (UL CoC.zip)

Question 8

What is the download  link for the trial version of Unity Pro XL 8.0 ?

Accepted Answer

Please check the link below to download Unity Pro S/L/XL V8.0 trial version , taking into consideration that the Unity Pro trial software will run for 21 days before it expires.

Question 9

What is meant by Symmetrical and Asymmetrical breaking currents?

Accepted Answer

issue:Customer wants to know the value of the symmetrical and asymmetrical breaking current of the circuit breaker and what do they mean.Environment:Circuit Breaker Resolution:- Symmetrical breaking current is the RMS value of AC component of short circuit current at the instant of separation of the contacts. It does not take into account the DC offset.- Asymmetrical breaking current is is the RMS value of the combined sum of the DC and AC components of the short circuit current at the instant of separation of the breaker contacts. This DC offset is of decaying nature which is dictated by the time constant of the system. As shown in the above picture the DC offset decays in a few cycles and is left only with the symmetrical component. Hence if a breaker has to close before the DC component decays, then the breaker’s breaking capacity is to be calculated for the asymmetrical current at the time of breaking.

Question 10

How to reset Zelio logic password?

Accepted Answer

The password can be reset by clearing the program inside the Zelio either byTransfering a new program to the ZelioOr Clearing the program that already exist by updating the firmwareKindly find the steps a) Clearing the program.b) Module / Update module firmware.c) Clear the Program Contained in the Smart Relay

Question 11

What is the selection criterion of Circuit Breakers for the Capacitor bank application.

Accepted Answer

The selection should be done after derating the Circuit Breaker taking into consideration voltage variation and capacitors tolerances that could increase nominal current up to 1.5In. The Derating factor of 1.5In Where In = Q/ ( Square root of 3 ) Un Q = Capacitor Power Un = Nominal Voltage Choose the Micrologic with delay time selection, so that the Circuit Breaker does not trip due to initial high inrush current. Also to be taken into account are the parameters like supply frequency, operating voltage & harmonics level of the power system for such application. Refer the attached sheet for further details for selection of Circuit Breaker for Capacitor duty application. Note: Use the phase barrier between the phases in Circuit Breaker to prevent flashover due to heavy inrush current.

Question 12

In a 3 phase system, why does the meter still show voltage reading on one of the phases even after breaking the phase circuit?

Accepted Answer

Issue:Testing phase loss on a meter doesn't result in a null voltage reading.Environmnet:EasyLogic Series Power MetersPowerLogic Series Power MetersResolution:The voltage seen is what we call "phantom voltage", its a known phenomenon with all high impedance power meters. These phantom voltages are normal artifacts of the design and should not pose any safety concerns to the end user.In some cases it'll probably disappear by power cycling the meter. Most power meters are not designed to monitor phase loss, as it'll always assume the presence of the 3 phases and the neutral, depending on your parameters setup. External devices are used to detect such occurrences, like phase control relays.

Question 13

Which RL(lead resistance from CT to relay) is to be used in Knee Voltage calculation if Current Transformers (CTs) used in High Impedance Restricted Earth Fault are at different distances from relay?

Accepted Answer

Issue:Having two different values for RL ( Lead resistance from the CT to the relay); RL from the phase CT to the relay and RL from the neutral point CT to the relayEnvironment:Protection Function ANSI 64refHigh impedance differentialSepam 80 Current Transformer requirementResolution:In any application where the high impedance differential is used, all the CTs must have the following:- the same ratio,- the same magnetizing curve (same minimum Vk),- the same maximum Rct (current Transformer secondary winding resistance),- if the relevant CTs are not at the same distance from the relay, take the maximum RL.Attached Cahier Technique no.194 for more information about high impedance calculation

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