DANGER. DANGER indicates an imminently hazardous situation which, if not avoided, will result in death or serious injury. WARNING

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1 Septembre 2015

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3 Safety Information Important Information Read these instructions carefully before trying to install, configure, or operate this software. The following special messages may appear throughout this bulletin or on the equipment to warn of potential hazards or to call attention to information that clarifies or simplifies a procedure. The addition of either symbol to a Danger or Warning safety label indicates that an electrical hazard exists which will result in personal injury if the instructions are not followed. This is the safety alert symbol. It is used to alert you to potential personal injury hazards. Obey all safety messages that follow this symbol to avoid possible injury or death. Please Note DANGER DANGER indicates an imminently hazardous situation which, if not avoided, will result in death or serious injury. WARNING WARNING indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury. CAUTION CAUTION indicates a potentially hazardous situation which, if not avoided, could result in minor or moderate injury. NOTICE NOTICE is used to address practices not related to physical injury. The safety alert symbol shall not be used with this signal word. Electrical equipment should be installed, operated, serviced, and maintained only by qualified personnel. No responsibility is assumed by Schneider Electric for any consequences arising out of the use of this material. A qualified person is one who has skills and knowledge related to the construction, installation, and operation of electrical equipment and has received safety training to recognize and avoid the hazards involved.

4 Safety Precautions WARNING HAZARD OF INCORRECT INFORMATION Do not incorrectly configure the software, as this can lead to incorrect reports and/or data results. Do not base your maintenance or service actions solely on messages and information displayed by the software. Do not rely solely on software messages and reports to determine if the system is functioning correctly or meeting all applicable standards and requirements. Consider the implications of unanticipated transmission delays or failures of communications links. Failure to follow these instructions can result in death, serious injury, or equipment damage. The information provided in this documentation contains general descriptions and/or technical characteristics of the performance of the products contained herein. This documentation is not intended as a substitute for and is not to be used for determining suitability or reliability of these products for specific user applications. It is the duty of any such user or integrator to perform the appropriate and complete risk analysis, evaluation and testing of the products with respect to the relevant specific application or use thereof. Neither Schneider Electric nor any of its affiliates or subsidiaries shall be responsible or liable for misuse of the information that is contained herein. If you have any suggestions for improvements or amendments or have found errors in this publication, please notify us. No part of this document may be reproduced in any form or by any means, electronic or mechanical, including photocopying, without express written permission of Schneider Electric. All pertinent state, regional, and local safety regulations must be observed when installing and using this product. For reasons of safety and to help ensure compliance with documented system data, only the manufacturer should perform repairs to components. When devices are used for applications with technical safety requirements, the relevant instructions must be followed. Failure to use Schneider Electric software or approved software with our hardware products may result in injury, harm, or improper operating results. Failure to observe this information can result in injury or equipment damage Schneider Electric. All rights reserved.

5 IMDs are used for the monitoring of IT (ungrounded) networks. VSDs are also present in IT networks. The tests performed here are aiming at showing the compatibility between these two types of products which will be installed on the same electrical network. This Application Note is also providing recommendations regarding the installation of VSDs on IT Networks, and recommendations for IMD settings when there are VSDs on the network.

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7 As a consequence, in case of insulation fault, there will be no dangerous touch voltage, and the faulty current will remain very low. IT Earthing Systems is the one which guarantees the best continuity of service. Indeed, even in the presence of a first insulation fault, the operation can continue, there is not need to trip the protections since there is no danger for people. However, the detection of the insulation fault and its repairing must be done, before a second insulation fault occurs on the installation. Indeed, a second insulation fault would lead to a short circuit on the network, meaning the trip of protections and the loss of continuity of service.

8 Continuity of Service is a fundamental requirement for the electrical networks. In addition, the installation should respect the specific rules related to protection of goods and persons. These security constraints imply the presence of protections which will act in case of danger, and will lead to a temporary shut down of the network. Consequencies of a shut down can be serious: Partial or total stop of the process Partial or total loss of the raw material involved in the process Many fires are started by intense, concentrated heating or by an electric arc from an insulation fault. The higher the fault current, the greater the risk. A point of contact between a conductor and a metal part may, in particularly sensitive areas, start a fire when the fault current exceeds 500 ma. In environments where a risk of explosion exists, the consequences will be even more serious.

9 Applications below typically use IT earthing systems. Most of the time, IT is only implemented in a limited portion of the electrical network.

10 IT Networks are described by several standards: These standards clearly state that, with the IT earthing system, the installation must be isolated from earth or connected to earth through a sufficiently high impedance. In the event of only one ground or earth fault, the fault current is very low and interruption is unnecessary. Since a second fault would cause a circuit breaker to trip, an insulation monitoring device (IMD) is required to indicate an initial fault. This device must activate an audible and/or visual signal. IMDs are mandatory in IT networks that have more than one feeder. An insulation monitoring device injects DC or low-frequency AC voltage between the network and earth. The resulting current that flows through the IMD is then measured. The insulation value is calculated from this low-frequency current. The IMD indicates the fault locally on its front panel depending on the adjustable threshold set on the device. It activates a relay output which can be connected to a visual or audible indicator. Display the insulation resistance value Display the leakage capacitance of the network Store time stamped alarms Communicate with a Supervision system

11 On networks with many circuits, the IMD can be associated with a Locator (XD301, XD312, XD308 or XL308, XL316) that can identify the faulty circuit. Such locators use the 2.5 Hz signal injected by the IMD to determine through which circuit the fault current is flowing. These locators can be fixed devices connected to toroids that measure the injected current, or they can be mobile devices. XD312 and XD301 can monitor 12 circuits or 1 separate circuit. Advanced versions of these locators (XL308, XML316 and XML3xx) provide the insulation value on a circuit by circuit basis. This greatly simplifies maintenance of large networks.

12 There are many applications where Variable Speed Drives can be found on IT ungrounded networks. Here are typical applications where Variable Speed Drives are needed, and where part of the network can be in IT. Feeders, conveyors, Mills, separators Stackers, reclaimers Crushers, slurry pumps, Rotary kilns Tunnel boring machines (TBM) Hoist applications, converter tilt devices Hoist applications (winches, cranes) Propulsion Thrusters (azimuth-, tunnel- and jet thrusters) Seawater and mud pumps HVAC applications Distribution pumps, chemical pumps Decanter centrifuges Mixers Archimedes screws Compressors Osmosis Desalination Industrial cranes for heavy loads Harbour cranes Overhead travelling and gantry cranes Special cranes Force draft (FD) and induced draft (ID) fans Feed-water pumps Cooling water pumps Oil and fuel pumps Conveyors for material transport Compressors Crushers, mills Oil-line pumps, Jack pumps Slurry pumps Submersible pumps Oil-swapping pumps Drilling rigs

13 Checking the Installation Guide of the VSD is mandatory to get detailled instructions. For example, for the Altivar 71 (type ATV71H U22Y to D90Y), the RFI filters connection to the ground must be disconnected. Below is an extract from the manual (Altivar 71- Installation Guide). In case of incorrect wiring, the risk is to connect the IT network to the ground, meaning that the IMD will indicate permanently an insulation fault, or to damage the VSD. Regarding the selection of protections on an IT network with Variable Speed Drives, you may refer to the White paper: Cahier Technique n 204 LV Protection Devices and Variable Speed Drives (see link in Appendix).

14 IMDs which inject a DC component are not compatible with networks including Variable Speed Drives. This is the case of the Vigilohm IM9: its measurements can be misled by a fault causing a DC voltage between the line supply and the earth. Depending on the polarity of this voltage, the insulation level will be falsely increased or decreased. Only AC injection IMDs can therefore be used on networks with Variable Speed Drives. This corresponds to the following Vigilohm IMDs: IM10, IM20, IM400, XM300 and XML3xx. IM1 and IM20 IM400 XM300 and XML3xx In permanent operation of the VSD, these IMDs are compatible with speeds higher than 10Hz. In transient operation of the VSD, these IMDs are compatible with speeds lower than 10Hz only for durations inferior to 10 seconds. This Application Note will not provide detailed test results on the XM300 / XML3xx performance since it is recommended, whenever possible, to use IM10, IM20, or IM400 IMDs on installations which include Variable Speed Drives. Indeed, they are the latest generation of IMDs, for which the injection principle has been improved. They are particularly well suited for networks with VSDs.

15 During the tests, we have identified the key parameters for our configurations which could potentially cause disturbances. We have tested the most critical cases to validate the proper behavior of the IMD, and determine its limitations- if there were any. Type of IMD Type of VSD IM10 and IM20 have the same principle of measurement. IM400 has a different principle of measurement > Ensure of the IMD performance for each type of IMD The technology and Power of the VSD could affect in different ways the IMD measurements > Test IMDs with several types of VSD Vigilohm IM20 Vigilohm IM400 ATV71HU75N4 ATV71HD45N4 ATV71HD90N4 ATV630D22N4 Number of VSDs on the Network Location of the Insulation Fault If several VSDs are connected on a same network, there could potentially be intermodulation frequencies generated on this network > Ensure that IMD is not disturbed if there are several VSDs Insulation fault may happen: - Upstream from the VSD - In the VSD - Downstream from the VSD > Generate insulation faults in different locations to ensure they are always detected by the IMD Installation with one VSD Installation with two VSDs Most of the tests have been done with insulation faults downstream from the VSD, because this is the most critical case See Note below Value of the Insulation Fault (kohms) Network Earth Leakage Capacitance (in µf) IMD performance may be impacted by the insulation value > Create insulation faults of several values An important earth leakage capacitance leads to a network which is not healthy. This parameter also influences IMD accuracy. > Perform the tests for several values of network capacitance 0 kohm (zero-impedance fault) 1 kohm 4,7 kohms 10 kohms 47 kohms 3µF 30µF 120µF

16 The IT network and the location of the insulation fault can be represented like the following: Variable Speed Drive Upstream Fault Fault in VSD Downstream Fault Motor IMD CPI Network capacitance Earth The main point of attention is the case of Insulation Faults happening downstream from the Variable Speed Drive. Indeed, the VSD does not disturb IMD measurements if the insulation fault happens upstream or inside from the VSD.

17 IMD Filtering (in seconds) This parameter corresponds to the time given to the IMD to perform the insulation measurement > Determine the recommended setting. On installations which include VSD, it could be required to increase this parameter, to ensure IMD measurements are more stable IM20: 4 seconds and 40 seconds IM400: Medium (default value for the Mode: Power Circuit) (This parameter is particularly relevant for the IM20) Use of IMD together with a Fault Locator (Fault Locating parameter) The parameter Fault Locating has to be set to ON if the IM400 works along with locators. With this, in case of insulation fault the injected signal of the IM400 is automatically adjusted to become compatible with XD3xx location (it changes from 1,25Hz Sinus to 2,5Hz Square) > Verify the impact of Fault Locating=ON OFF (if IM400 alone) ON (if IM400 + Locators) (This parameter only exists for the IM400)

18 VSD Speed (in Hz) This is the most important parameter. This corresponds to the frequencies that the VSD will induce on the network. > Check that the IMD is operational for any speed, in particular for speeds close to the injection frequency of the IMD 1 Hz, 2 Hz, 2,5 Hz 3 Hz, 4 Hz, 5 Hz 10Hz, 20Hz, 30 Hz 35Hz (there is a change of modulation type of the VSD at this frequency) 50 Hz 60 Hz Switching Frequency (in khz) > Check that the IMD is operational for any switching frequency 2,5 khz 4 khz 8 khz 16kHz Length of cable between VSD and motor Length of cable induces an earth leakage capacitance, in particular shielded cable > Verify influence of this parameter on the IMD 5 meters 100 meters (shielded cable) Use of Sinus Filter This filter induces an earth leakage capacitance. > Verify influence of this parameter on the IMD With Sinus Filter Without Sinus Filter Use of Internal Filter This filter induces an earth leakage capacitance. > Verify influence of this parameter on the IMD With Filter Without Filter

19 Variable Speed Drive 100 meters of shielded cable Motor Variable Speed Drive 1 Variable Speed Drive 2 Motor 2 1,5kW 230V Delta IMD Network Capacitance VSD Capacitance IMD Network Capacitance Motor 1 1,5kW 230V Delta Earth

20 Tests showed the following results. The only situation where VSDs could disturb IMD measurements is the situation of an insulation fault happening dowstream from the VSD, on the motor side. In other situations (insulation fault upstream or in the VSD), IMD measurements are not disturbed by the VSD. IMD measurements are not affected by the inter modulation frequencies which are due to the presence of several VSDs on the network. IMD measurements are not affected by the length of cable between VSD and motor. Tests done with 100 meters of shielded cable showed IMD measurements were not affected. IMD measurements are not affected by the switching frequency value of the VSD. IMD measurements are not affected by the Network Capacitance (as long as this capacitance stays within the IMD specification range). IMD measurements are not affected by the use of an internal filter in the VSD. IMD measurements are not affected by the VSD speed as long as this is higher than 2Hz. If the speed is lower than 2Hz, IMD Filtering must be set at 40 seconds. Note: In this configuration, IMD measurements can fluctuate if the VSD permanently works below 2Hz. However, these fluctuations stay around the actual insulation value, so we can consider that the IMD is operational. Note: The Altivar VSDs used during these tests did not allow testing the situation of a VSD working exactly at 1,25Hz (which corresponds to the injection frequency of the IM10 and IM20). This frequency is not available with these VSDs. It seems unlikely to find an installation where the VSD would permanently work at 1,25Hz.

21 Tests showed the following results. The only situation where VSDs could disturb IMD measurements is the situation of an insulation fault happening dowstream from the VSD, on the motor side. In other situations (insulation fault upstream or in the VSD), IMD measurements are not disturbed by the VSD. IMD measurements are not affected by the inter modulation frequencies which are due to the presence of several VSDs on the network. IMD measurements are not affected by the length of cable between VSD and motor. Tests done with 100 meters of shielded cable showed IMD measurements were not affected. IMD measurements are not affected by the use of an internal filter in the VSD. Notice that the IMD will measure the global network capacitance which takes into account the internal filter capacitance. IMD measurements are not affected by the switching frequency value of the VSD. IMD measurements are not affected by the use of a Sinus filter in the VSD. IMD measurements are not affected by the Network Capacitance (as long as this capacitance stays within the IMD specification range). IMD measurements are not affected by the VSD speed as long as this is different from 2,5Hz. If the VSD speed is equal to 2,5Hz, and if IM400 FAULT LOCATING=OFF: the IM400 will be operational. If the VSD speed is equal to 2,5Hz, and if IM400 FAULT LOCATING=ON: IM400 measurements will be fluctuating. Note: if the VSD speed is equal to 2,4Hz or below; or equal to 2,6Hz and above: the IM400 will be operational, which shows its good frequency selectivity.

22 Tests showed the following results. The only situation where VSDs could disturb Locator measurements is the situation of an insulation fault happening dowstream of the VSD, on the motor side. In other situations (insulation fault upstream or in the VSD), Locator measurements are not disturbed by the VSD. Locator measurements are not affected by the inter modulation frequencies which are due to the presence of several VSDs on the network. Locator measurements are not affected by the length of cable between VSD and motor. Locator measurements are not affected by the use of an internal filter in the VSD. Locator measurements are not affected by the switching frequency value of the VSD. Locator measurements are not affected by the use of a Sinus filter in the VSD. Locator measurements are not affected by the Network Capacitance (as long as this capacitance stays within the locator specification range). Locators are operational for VSD speeds higher than 10Hz. For VSD Speeds lower than 10Hz, locators may be disturbed (for example, they may signal an insulation fault, while the IMD does not). In many cases, frequencies lower than 10Hz correspond to a transient phase (start, stop of a motor). If the Locators signal false faults due to this transient phase, the following solution may be implemented. The XD3xx will be kept powered OFF, and will only be powered ON when the IM400 detects an insulation fault. For this, the IM400 alarm relay will be used.

23 Tests have been performed for network capacitances equal to 3µF, 30µF and 120µF. However, it is necessary to keep in mind that high network capacitance leads to a faulty current, in case of first fault, which is no longer negligible. Below are some examples of values: A 3-phase network of 30µF, nominal voltage of 230V, can see a 1 st fault (zero-impedance fault) current equal to 1,3A A 3-phase network of 30µF, nominal voltage of 400V, can see a 1 st fault (zero-impedance fault) current equal to 2A A 3-phase network of 120µF, nominal voltage of 230V, can see a 1 st fault (zero-impedance fault) current equal to 5A A 3-phase network of 120µF, nominal voltage of 400V, can see a 1 st fault (zero-impedance fault) current equal to 8,5A These Current values are not specific to networks including VSDs.

24 IMD IT VSD Insulation Monitoring Device Ungrounded Earthing System (isolated from ground) Variable Speed Drive Cahier Technique n 204 LV Protection Devices and Variable Speed Drives Vigilohm Catalogue FAQ_ Can you use ATV61 and ATV71 drives on a high resistance to ground system Test Report _ Compatibility of IM10, IM20 with Variable Speed Drives Contact Us Test Report _ Compatibility of IM400, XD312, XRM with Variable Speed Drives Contact Us Altivar Brochure

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