FAQ

General, Fault Detectors

Q: What is unique with Protrol's earth fault detection algorithm?

A: Protrol's algorithm determines the fault direction without any voltage reference by
analysing the three phase currents. These are measured by current transformers,
easy to mount.

In addtion, the detection algorithm has a high sensitivity and reliability for high
impedance and transient faults.

Q: Why are Protrol's detectors so cost efficient?

A: The total cost for the installation becomes low since the accuracy is competible
   with that of the best watt-metric relays although no voltage measuring bay
   is required.

   With built-in RTU functionality further savings can be achieved. The IPC fault
   detector is optimized for use in a typical secondary substation, with respect to
   measuring, indications and control.

Q: How sensitive is the algorithm for earth fault detection?

A: The sensitivity when 5 A neutral resistance, is 5 kOhm phase-ground resistance
for earth faults when 300/1 current transformers are used. Reduced ratio means
that the sensitivity increases correspondingly. The Swedish utility Vattenfall has
successfully verified the detecors with 10 kOhm earth faults.

Q: What equipment is required for fault detection?

A: A fault detector and three current transformers, one for each phase.

The current transformers are available as split-core and can be mounted after
the cables have been connected to the secondary substations.

Protrol Delbara Strömtransformatorer

Delbara Strömtransformatorer

Q: Does a fault detector identify both overcurrent and earth faults?

A: Yes.

Q: How many fault detectors are needed in a secondary substation?

A: "The number of bays minus 1". It does not matter if the incoming or outgoing
   bay is equipped with the fault detector. In the example to the right three IPS 2
   are connected to one PDC remote terminal unit that sends the indications to the
   control center.

    It is possible to have fault detection in up to three lines if one IPC4020exp is employed.

Protrol IPS2 radialer

IPS2 för radialer med PDC

Q: Is it required to change the settings if the open point is moved within the loop?

A: No. The detectors determine if the fault current has passed the detector. If the
power direction is known then it is easily understood on which side of the detector
the fault can be found. The detector to the right detects the fault in the example
to the right.

Protrol IPS2 vid omkopplingar

IPS2 vid omkopplingar

Q: What does it mean when the detector signals that it has Started?

A: It means that the detector has identified a pass through fault current. Thus, the
Start signal is a strong indication that there has been at least a transient fault in
forward direction.

Q: How fast does a fault detector return to normal state after a fault?

A: It gets ready to identify the next fault when the residual current I0 disappears.

Q: Are there situations when the fault detector cannot see the earth fault?

A: Theoretically, a slowly increasing earth fault can be difficult to see since the
algorithm is of transient type and eliminates the load currents - however, that
is not how earth faults acts in reality.

Q: How do you verify that the fault detector functions?

A: If the fault detector measures a load current: Use a short (< 5 cm) insulated
   wire and short-circuit one of the current inputs distinctly. Keep the wire in position
   and wait until the set time has passed. The indicator shall signal an earth fault.

If the fault detector is not connected: Use a current generator to inject a current
   on two inputs but reversed so that the residual current I0 becomes zero. Use the
   method described above to simulate an earth fault.

Q: Which utilities in Sweden uses Protrol's products for grid automation?

A: Approximately 30% of the utilities in Sweden use Protrol's fault detectors.

IPS Light / IPS Relay / IPS2 230 VAC - Fault detectors for stations without communication

Q: How do you supply an IPS that requires 230 VAC?

A: Typically, from the low voltage side of the transformer.

When the protective relay in the primary substation operates, the detector
senses the voltage loss and starts to indicate if the fault has passed or not.

Protrol lokal indikering av fel

Protrol indikering av fel med IPS Light eller IPS2

Q: Can you deactivate the voltage requirement, i.e., that there shall be no supply
   voltage before the external LED is activated?

A: Yes. Under the cover there is a dip-switch mounted near the top-left corner on
   the circuit board. Set the dip-switch number 1 to position ON and the IPS Light
    will activate the external LED as soon as it has seen the fault current.

Protrol IPS Light DIP 1

IPS Light DIP 1 spänningsvillkor

Q: How do you configure an IPS Light / Relay unit?

A: There are no special settings for these units.

Protrol IPS Light

Feldetektor med LED

Q: How do you configure an IPS2 230 VAC?

A: IPS2 230 VAC has two rotation switches on the front panel, one for overcurrent
and one for earth faults.

Each current level can be combined with typical operate times.

Protrol IPS2 230 VAC

Feldetektor utan inbyggd RTU

Q: Does IPS Light / IPS Relay / IPS2 230 VAC require any special maintenance?

A: No. They do not use batteries for the external LED but super capacitors that are
maintenance free.

Protrol IPS Light DIP 1

IPS Light DIP 1 spänningsvillkor

IPS2 24 VDC - Fault detector with built-in RTU

Q: How do you connect an IPS2 24 VDC to the control center?

A: IPS 24 VDC has two possibilities for monitoring:

1. It has a built-in RTU function for communication via IEC 60870-5-101
2. It can be connected to a separate RTU in the secondary substation with its
binary outputs.

Q: What output signals can be sent by an IPS 24 VDC?

A: The units can be ordered with the following binary output signals::

- Start EF/OC, Trip EF/OC
- Watchdog, Trip EF/OC
- EF Trip, OC Trip

For a list of IEC 60870-5-101 objects, see the datasheet.

Q: How do you configure an IPS2 24 VDC?

A: IPS2 24 VDC has four rotation switches on the front panel. Two controls the
overcurrent settings while the other two controls the settings for earth faults.

On rotation switch in each group defines the current level, while the other controls
the operate time.

Protrol IPS2 24 VDC

Feldetektor med inbyggd RTU

Q: Does IPS2 24 VDC require any special maintenance?

A: No.

IPC4010 / IPC4011 / IPC4012 - Fault detectors with built-in RTU and I/O for a typical secondary substation

Q: What protocols are supported for IPC401x?

A: Standard is IEC 60870-5-101 for IPC4010 and IPC4011. For IPC4012 the
standard is IEC 60870-5-104. It is also possible to choose RP570 for IPC4010 at
order.

Q: What protocols are supported for IPC4020?

A: Standard are IEC 60870-5-101 and IEC 60870-5-104.

Q: Are both overcurrent and earth fault signaled using the protocol?

A: Ja. Start OC, Start EF, Trip OC and Trip EF are transmitted.

Q: Is any other information transmitted by the protocol?

A: Ja, phase currents (rms), temperature, indications and orders.

Q: Is it possible to acknowledge/reset the local indications from the control center?

A: Yes. It is also possible to configure an auto-acknowledge time.

Q: Can you configure an IPC4012 using Ethernet.

A: Yes. It is possible to change communikation parameters in the Protrol Settings
and Config Tool 2.

Q: Are any transient fault recordings stored by an IPC?

A: Yes. Using Protrol Tool it is possible to visualise and analyse information from the
last two disturbances.

Q: Does the IPC models require any special maintenance?

A: No.

PDC

Q: Does PDC or the I/O-modules require any special maintenance?

A: No.