Description 2.3 Protection system • Directional short time dST • Reverse power protection RP • Enhanced protective functions EPF All of the protective functions can be independently enabled “ON” or disabled “OFF”. 2.3.5.2 Long time LT The overload protection is current-dependent and long-time delayed. It is based on the rms value of the current and protects cables, busbars and busway systems in the event of overload.
Description 2.3 Protection system Phase failure detection If the current of the phase with the lowest load is 50% less than the current of the phase with the highest load, this is interpreted as a phase failure and the setting Ir is automatically reduced to 80%. If the three phase currents do not differ by more than 50% with respect to each other, the setting Ir applies again. Phase failure detection can be switched on/off for the ETU600 electronic trip unit.
Description 2.3 Protection system 2.3.5.3 Short time ST With short time ST, the power distribution system is protected against power system faults such as: • Phase-phase short-circuit • Phase-neutral conductor short-circuit • Phase-ground short-circuit The circuit breaker trips when the rms value of a phase current or the neutral current exceeds the setting of the short-time-delayed tripping current for the duration of the set delay.
Description 2.3 Protection system 2.3.5.4 Instantaneous short-circuit protection INST With the instantaneous short-circuit protection, the power distribution system is protected against power system faults such as: • Phase-phase short-circuit • Phase-neutral conductor short-circuit • Phase-ground short-circuit The circuit breaker trips when the rms value of a phase current or the neutral current exceeds the setting of the instantaneous tripping current Ii.
Description 2.3 Protection system 2.3.5.5 Neutral protection N The neutral conductor can be protected against overload and short-circuit with the electronic trip unit. The neutral protection consists of a separate overload protection and a common short-circuit protection for the three phases and the neutral conductor. The overload protection has the setting IN. The delay, the overload characteristic, and the thermal memory correspond to the settings of the overload protection of the three phases.
Description 2.3 Protection system 2.3.5.6 Ground-fault alarm A ground fault can occur due to aging and the resulting deterioration of an insulating component in a power distribution system or due to a foreign body in the system. If the fault resistance is so high that the ground-fault current is below the settings of the ground-fault protection, the electronic trip unit will not trip. With the ground-fault alarm, a high-resistance ground fault can be detected without switching off the system.
Description 2.3 Protection system 2.3.5.7 Ground-fault protection GF The ground-fault protection detects residual currents between the conductors and grounded parts of the power distribution system. The ground-fault protection function responds when the ground-fault current exceeds the set tripping current Ig for the set delay time tg. Ground-fault protection can be implemented either as a current-independent or a currentdependent function.
Description 2.3 Protection system NOTICE Damage to electronic trip unit (ETU) due to incorrectly dimensioned current sensor The measuring input of the electronic trip unit is designed for a maximum ground fault sensor secondary rated current of 4 A for 500 ms. This value must not be exceeded. The selection of the current sensor must take into account the internal circuit breaker load of 0.11 Ω. The transformation ratio of the current sensor must be set on the ETU600 electronic trip unit.
Description 2.3 Protection system GF Direct The ground-fault current is measured directly, e.g. in the cable of the transformer neutral point, with a current transformer. Commercially available measuring transformers with primary rated current Ipr = 150 A to 2000 A and secondary rated current Isr = 1 A can be used for this purpose.
Description 2.3 Protection system 2.3.5.8 Ground-fault protection GF Hi-Z In addition to the GF modes mentioned in the Chapter “Ground-fault protection GF”, the 3WA circuit breaker with the ETU600 LSIG Hi-Z electronic trip unit offers the possibility of connecting a current transformer combination for ground-fault protection Hi-Z between the transformer and the circuit breaker. The current transformer combination consists of several current transformers.
Description 2.3 Protection system (1) Restricted zone of protection (2) Unrestricted zone of protection Current transformer configurations Depending on the network topology of the power distribution system, several current transformers are required for the detection of ground-fault currents on the infeed side. In practice, current transformers of class TPS (former designation class X) according to IEC 60044-6 are used in a transformer combination.
Description 2.3 Protection system Ground fault interruption The ground fault on the outgoing side can be interrupted with the circuit breaker. When a ground fault is detected on the infeed side, the ETU600 LSIG Hi-Z electronic trip unit issues a signal to open the medium-voltage circuit breaker.
Description 2.3 Protection system Characteristic The characteristic is determined by the short-time-delayed tripping currents Isd FW (forward direction) and Isd REV (reverse direction) and the adjustable tripping time tsd FW and tsd REV.
Description 2.3 Protection system 2.3.5.10 Reverse power protection RP The reverse power protection trips the circuit breaker if the power flow through the device reverses against the direction of flow defined as normal and exceeds the set delay time. The setting is referred to the rated active power Pn as a percentage. This is dependent on the rated current In of the circuit breaker and the rated voltage Un parameterized on the electronic trip unit.
Description 2.3 Protection system 2.3.5.11 Enhanced protective functions EPF Enhanced protective functions can be added to the function scope of the ETU600 electronic trip unit. On the basis of the measured currents, voltages and frequency, overshooting or undershooting of the resulting metering values can cause tripping of the circuit breaker.
Description 2.3 Protection system 2.3.6 DAS+ maintenance mode An arcing fault can be described as a gas discharge with plasma formation and temperatures up to 50,000 K, in which the electric current flows through unintended dynamic paths. In addition to the extreme temperatures, very high pressures are also generated.
Description 2.3 Protection system DAS+ system The following shows how to integrate several circuit breakers in the DAS+ maintenance mode. The activation is done via a switch. The activated maintenance mode on all the circuit breakers is signaled by a “DAS+ active” light. (1) To ensure proper performance, the total cable length of the system must not exceed 50 m (165 ft). (2) The “DAS+ active” light should be installed in such a way that it is clearly visible to maintenance personnel.
Description 2.3 Protection system Activation The DAS+ maintenance mode can be activated in various ways. Activation options: • Digital ETU input of the circuit breaker, secondary disconnect terminals X8-5 and X8-6. Depending on the selected signal state (LOW/HIGH), the input can be controlled via an NC contact or an NO contact.
Description 2.3 Protection system The digital ETU output, secondary disconnect terminals X8-7 and X8-8, is used for signaling “DAS+ ON”.
Description 2.3 Protection system 2.3.7 Activation limits and power supply The electronic trip unit does not require auxiliary power. The electronic trip unit is powered by the circuit breaker’s internal current sensors.
Description 2.4 Electronic trip unit ETU600 2.4 Electronic trip unit ETU600 2.4.1 Overview of variants All the circuit breakers with integrated ETU600 electronic trip units have two independently operating microprocessors - one for protective functionality and one for metering and accessory functionality. Function packages can be added to the ETU600 electronic trip unit to add protective functions and additional measurement capabilities.
Description 2.4 Electronic trip unit ETU600 2.4.2 Operator controls, displays and voltage tap module 2.4.2.
Description 2.4 Electronic trip unit ETU600 2.4.2.2 Display and operating keys F1 to F4 The ETU600 electronic trip unit has an integrated color display. This can be used to display metering values, set parameters, and report events. The four operating keys F1 to F4 are assigned menu-dependent actions. One to four operating keys can be active. (1) Action that is executed by the assigned operating key (2) Operating keys The display is also used for detailed representation of events.
Description 2.
Description 2.4 Electronic trip unit ETU600 2.4.2.4 Rotary switch The electronic trip unit has five rotary switches for parameterizing the basic protective functions. Nine fixed values can be set mechanically for each rotary switch. The tenth position is marked with “e.SET”. In this position, the parameter can be set via the display or with the help of the SENTRON powerconfig configuration software via Bluetooth or communication. The basic settings for the “e.
Description 2.4 Electronic trip unit ETU600 2.4.2.5 Voltage tap module A voltage tap module VTM is required for measuring the voltage and calculating further metering values. It is available as an option for 3WA circuit breakers with rated voltage up to 1000 V and ETU600.
Description 2.4 Electronic trip unit ETU600 Test position Before performing the insulation test of the power distribution equipment, the voltage tap module must be pulled out into the test position. This provides galvanic isolation between the electronics and the primary circuit. Note Performing an insulation test without pulling the voltage tap module into the test position may result in a failed insulation test. This will not affect the circuit breaker functionality.
Description 2.4 Electronic trip unit ETU600 2.4.3 Display and menu structure 2.4.3.1 Operating philosophy For a simple and intuitive operation of the ETU600 electronic trip unit, the following two properties are important: • In each menu, the menu name and the corresponding menu number are displayed in the top line. • The operating keys F1 to F4 have a menu-dependent assignment.
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Description 2.4 Electronic trip unit ETU600 Additional symbols If a menu has to be displayed across several pages, this can be recognized by the following symbols on the right-hand side: Icon Meaning Scroll menu - further menu commands are located above the displayed menu commands Scroll menu - there are further menu commands below the displayed menu commands The following symbols are used to represent a state: Icon Meaning Status: OK Status: Error 2.4.3.
Description 2.4 Electronic trip unit ETU600 2.4.3.
Description 2.4 Electronic trip unit ETU600 Status bar In the status bar, the statuses of the circuit breaker are represented by symbols.
Description 2.4 Electronic trip unit ETU600 Maximum instantaneous value of the phase current The maximum phase current as a percentage of the overload protection setting is displayed as a numerical value. A colored bar chart shows the level of the current.
Description 2.4 Electronic trip unit ETU600 2.4.3.4 Display after a trip Note Trip indication via the display is only possible with an activated ETU600 electronic trip unit. Alternatively, after pressing the “QUERY” button on the ETU front, the last trip cause can be displayed via LED. If the electronic trip unit was activated without interruption for two hours or more, the trip cause LED can light up for at least 10 s.
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Description 2.4 Electronic trip unit ETU600 2.4.3.5 Display in case of a warning Warnings are indicated by a yellow INFO LED and shown on the color display of the ETU600 electronic trip unit. The warning is acknowledged by pressing the F4 operating key. Afterwards, the time stamp and details of the warning will be visible on the display. After pressing the operating key F4 again, the warning disappears and the last selected menu appears.
Description 2.4 Electronic trip unit ETU600 2.4.3.6 Display of an error message Detected errors are indicated by a red INFO LED and shown on the display of the ETU600 electronic trip unit. The error is acknowledged by pressing the F4 operating key. Afterwards, the time stamp and details of the error are shown on the display. After pressing the F4 operating key again, the full-screen error display disappears.
Description 2.4 Electronic trip unit ETU600 2.4.4 Interfaces 2.4.4.1 Bluetooth and USB-C interface USB-C interface The ETU600 electronic trip unit has a USB-C interface on the front. The electronic trip unit can be activated and parameterized via this interface. An overview of the interfaces on the front can be found in Chapter Overview (Page 70). The SENTRON powerconfig configuration software can be used for support.
Description 2.4 Electronic trip unit ETU600 To connect with a compatible device via Bluetooth, proceed as follows: 1. Select the “Device configuration” menu item in the main menu of the ETU600. 2. Select the menu item “Local interfaces”. 3. Select the “Bluetooth” interface and switch it on. Available devices and devices which have previously been paired are automatically connected.
Description 2.4 Electronic trip unit ETU600 4. If you want to connect a new device, activate pairing mode on the device to be paired and select ETU600 as the connection partner. Select the ETU600 menu item “Pair BT device”. A connection code is displayed. A prompt requesting you to enter the code appears on the device to be paired. 5. Enter the displayed code on the device to be paired. 6. Pairing is complete and the connected device appears on the ETU600 display.
Description 2.4 Electronic trip unit ETU600 2.4.4.2 Digital input and output The ETU600 electronic trip unit has one digital input and one digital output. Both can be configured on the ETU600 display in the device configuration menu or using the SENTRON powerconfig configuration software. The 24 V input can be used for the following: • Activating the DAS+ maintenance mode • Switchover to the second protection parameter set (parameter set B). The meaning of the input signal (low or high) is configurable.
Description 2.4 Electronic trip unit ETU600 2.4.4.3 Digital output for ground-fault alarm REF Note This output is only available with the ETU600 LSIG Hi-Z electronic trip unit. The ETU600 LSIG Hi-Z electronic trip unit has a digital output for signaling a detected ground fault on the infeed side of the circuit breaker. The ground fault can only be eliminated via the upstream medium-voltage circuit breaker.
Description 2.4 Electronic trip unit ETU600 2.4.4.5 Battery The internal clock of the ETU600 electronic trip unit is powered by a lithium battery. The charge status is shown in the status bar of the display. Battery full Battery empty, replacement necessary The service life of the battery depends on the ambient conditions; it is at least five years. The battery can be replaced on site.
Description 2.4 Electronic trip unit ETU600 2.4.4.6 Rear interfaces On the rear of the ETU600 electronic trip unit, there are terminals to ensure the circuit breaker functions. The terminals are only accessible after removing the electronic trip unit. The plug-in connections may only be disconnected for the exchange of the electronic trip unit.
Description 2.4 Electronic trip unit ETU600 2.4.5 Protection parameters 2.4.5.1 Parameter sets A and B Note Parameters can also be changed in the energized condition. However, parameters should not be changed in the energized condition, as the operator may experience unexpected tripping. The basic protective functions of the ETU600 electronic trip unit can be set quickly and easily using the rotary switches on the front of the ETU600, see Chapter Rotary switch (Page 73).
Description 2.4 Electronic trip unit ETU600 ETU600 LSI, ETU600 LSIG, ETU600 LSIG Hi-Z Protective function L: Long time LT, neutral conductor Tripping Current setting IN Current setting IN PAL S: delayed short circuit protection ST Tripping Current setting Isd Tripping time tsd Setting range Can be switched on/off 3-pole: 0.2 ... 2.0 x In 4-pole: 0.2 x In … In max 0.7 … 1.0 x IN Can be switched on/off 0.6 x In … 0.8 x Icw 0.02 … 0.
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Description 2.4 Electronic trip unit ETU600 2.4.5.2 Enhanced protective functions EPF parameters In addition to the two sets of protection parameters A and B, enhanced protective functions are optionally available for the ETU600 electronic trip unit.
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