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Residual Current is a critical condition impacting hospitals, data centres, industrial plants, etc. It can lead to dangerous situations for both personnel and equipment.<br>Moreover, it can cause unexpected interruptions, malfunctions and EMC problems that cost time and money. Hence, Residual Current Monitoring is critical for safety, high availability and productivity in industrial and purpose-built environments.<br>Inside environments like data centres where shielded cables are present, residual current may spread through cable shielding across different parts of the data centre if the racks are i
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RESIDUAL CURRENT MONITORING (RCM)PREVENT ELECTRICAL FIRE & HAZARDS www.messungelectricalengineering.com
CONTENTS • What is Residual Current and why you should care • Types of Residual Current Monitoring • Residual Current Monitoring Devices • Janitza APPs and software for RCM www.messungelectricalengineering.com
REASONS • Insulation Failures • Bad Practices • Unsafe Environment www.messungelectricalengineering.com
WHAT IS RESIDUAL CURRENT? • Electrical current that occurs in anunwantedconductive path • It flows from either AC or DC circuit in equipment to the chassis, or to the ground • Residual currents are typically the result of insulation faults, defectiveequipment andcomponents (power supplies, electricalloads) causing outflow-related residual currents and stray currents in TN-Ssystems • RCM classification is based on frequency and waveformof the current that they can detect - Type A, Type B, TypeB+ www.messungelectricalengineering.com
WHY TO USE RCM (EARTH LEAKAGE MONITORING)? Ensure Continuous System Availability In Market segments with sensitive applications (e.g., Critical power locations, Hospitals, Industrial Manufacturing), an uninterrupted power system is of crucial importance. • Uninterrupted operation (Increased Uptime & Availability) of an installation is only ensured by continuous monitoring. • Continuous Residual Current Monitoring is the only method to detect dangerous fault currents at an early stage, thereby avoiding damage to the power system as well as preventing server or production downtimes. • RCM measurement in accordance with DIN EN 62020 offers the most reliable and safe alternative wherever the realization of Insulation Resistance Measurement or RCDs are not practical in an installation. Alarm Notification of Leakage Current helps pre-empt Breaker Tripping www.messungelectricalengineering.com
PROBLEMS CAUSED BY FAULT CURRENTS • Electric Shock • Breaker Tripping • Fire Hazard • Server and Computer Shutdown • Interruption of Communication Networks • Temperature Rise in Conductors resulting in Insulation Breakdown • Fast Corrosion of Metal Pipes • Production Shutdown • VSD / Inverter Faults • Sensor Malfunction • Overvoltage Problems • Overloaded Neutral Conductor Damage to the insulation Corrosion in Pipes caused by Leakage Current Overloaded N Conductor Data Centre Fire Damage www.messungelectricalengineering.com
INSULATION FAILURE-REASONS • Natural deterioration due to aging • Accelerated by excessive heat and moisture • Heat, moisture and dirt are main causes of insulation failure • Chemical deterioration • Mechanical damage • Sunlight • Excessive voltage stresses
RCM - HOW IT WORKS? • Conductors (L1, L2, L3, N) of the specific measurement point are to be monitored and passed through the RCM CT • In a fault-free system the sum of all currents is ZERO, so that in the current transformer no current is induced. • If a fault current is flowing, the current difference induces in the differential CT a mA current that is detected by our UMG device • Residual currents are typically the result of insulation faults, defective equipment and components (power supplies, electrical loads) Fault Current ≈ 0 System = OK Sum >> 0 Failure in the electrical system
RCM INSTALLATIONS Main Incomer Busbar RCM CT
RCM INSTALLATIONS RCM CT Sub Circuits DB
RCM INSTALLATIONS RCM CT Sub Circuits DB
RCM INSTALLATIONS RCM CT Single Phase Circuits Server Rack
TYPES OF RCM Sinusoidal alternating current pulsed direct current • TYPE A Smooth & pulsating direct current as well as alternating currents upto 2 kHz. • TYPE B • Smooth & pulsating direct current as well as alternating currents upto 20 kHz. • TYPE B+
RCM STANDARDS • Verification Standard IEC 60364-6; NEW! Revision… Edition 2.0 2016-04 • When RCM (Earth Leakage Monitoring) is installed and operational, there is“NO” requirement for Mains Power disconnection • Confirmation of correct rating and setting of monitoring devicesWhere a circuit is permanently monitored by an RCM in accordance with IEC 62020 or an IMD in accordance with IEC 61557-8, it is not necessary to measure the insulation resistance if the functioning of the IMD or RCM is correct. • The functioning of the RCM or IMD shall be verified. • INTERNATIONAL STANDARD • Low Voltage electrical installations – Part 6: Verification
ALTERNATIVE FOR RESIDUAL CURRENT MONITORING Insulation Testing as part of Preventive Maintenance • Both the ends of the cable need to be disconnected and then meggered for finding the insulation • Long testing times results in long shutdown times • Cumbersome procedure of disconnecting the terminated cables • Periodicity of the tests needs long term planning as well Insulation Monitors - Online • A popular measuring method is to superimpose a measuring DC voltage between the phase and PE conductor • This measurement procedure is suitable for monitoring conventional AC, 3(N)AC systems. If it is used in AC, 3(N)AC systems containing galvanically connected DC components, these DC currents will distort the measurement result. • Cost prohibitive Residual Current Breakers / Earth Leakage Relays • Trip the circuit causing incidents • Tripping is a surprise factor in the Facility • No Prediction only Prevention of major fire
BENEFITS OF RESIDUAL CURRENT MONITORING SIGNALING INSTEAD OF SHUTDOWN AVOID SYSTEM FAILURES IMPROVE FIRE PROTECTION MONITOR HIGHLY AVAILABLE ENERGY DISTRIBUTION SYSTEMS MAINTENANCE COST OPTIMIZATION PREVENT PRODUCTION INTERRUPTIONS
RCM – WHERE IS IT USED? APPLICATIONS • TN-S Systems • Drive Systems (Frequency Converters) • DC Applications • Hospital & Medical Facilities • Industrial Manufacturing • Data Centre & Critical Power Applications • Power Distribution Busbar • Rail Networks
FROM UTILITY INCOMER TO THE FINAL CIRCUIT – OUR RCM DEVICES MV & LV Supply (PCC) LV Main Distribution Switchboard Chiller Plants Sub-Distribution Switchboards, UPS Outputs PDU, Critical Power Supply Points & Busway Feed Box Out-going Circuits, Final Sub-Measurement & Busway Tap-Offs UMG 512-PRO UMG 509-PRO UMG 801 UMG 96-PA UMG 96RM-E UMG 96RM-PN RCM 202-AB RCM 201-ROGO UMG 20-CM
TYPE A RCM DEVICES UMG 512 PRO CLASS A PQM UMG 509 PRO UMG 96 RM-E UMG 96 RM-PN
TYPE A RCM DEVICES UMG 96 PA (with RCM module) UMG 806 RCM 201-ROGO
TYPE A RCM DEVICES UMG 20 CM RCM 202 AB
TYPE B RCM DEVICES UMG 96 RM-E UMG 96 PA (with RCM module) UMG 96 PQ-L (with RCM module) RCM 202 AB
TYPE B+ RCM DEVICES UMG 96 PA (with RCM module) UMG 96 PQ-L (with RCM module) RCM 202 AB
RCM 202-AB • Two-channel RCM device for measurement and monitoring according to the IEC 62020 standard • Comprehensive analytical tools • Up to a maximum residual current of 20 A • Measurement and monitoring of AC/DC residual currents type A/B/B+ in TN and TT systems (grounded AC systems) • Warning and alarm thresholds configurable for each channel separately • RS 485 interface (Modbus) • Two digital outputs • Two analogue outputs (interfaces 4 … 20 mA) • Harmonics up to 20 kHz (Type B+)
GridVis-RCM REPORT • Analyze and evaluate residual current violations with the GridVisRCM report • Receive statistics regarding threshold violations with graphically highlighted overviews • Setting of up to 4 threshold levels • Support of dynamic thresholds (RCM measuring device configuration!) • Custom text, customer logo and export in PDF and XLS format • Report creation can be carried out at custom time schedule • Automatically dispatch per E-Mail
RCM ANALYSIS APP • APP with extensive options for setting limit values and analyzing fault currents in detail • Up to 20 RCM channels can be managed and evaluated via a gateway • The evaluation covers all types of residual current with an associated frequency analysis • For example, 50 Hz, pure DC or high-frequency residual currents in the 20 kHz range can be displayed individually • In addition, the application enables the proven dynamic limit value formation with Janitza energy measuring devices • Energy measuring devices can be assigned to each of the 20 RCM channels and limit values can be calculated as a function of power
THANK YOU Contact us MESSUNG SYSTEMS PVT. LTD. 501, 502 & 503 Lunkad Sky Vista, Viman Nagar, Pune, India - 411 014. +91 20 6649 2800 | info@messung.com www.messungelectricalengineering.com