MicroSCADA X DMS600

Fault location along feeder, in minimum the remote controllable zone where the fault is, must be determined before isolation and restoration can be planned. DMS600 can use fault indicators to determine faulted area but can also make fault distance calculation using protection IED information like fault current magnitude (A) or measured fault reactance (ohm). Most accurate fault location estimate is crucial also in later phases when field crews are searching the faulted network line or component.

The isolation and restoration planning function offers support for planning of operations needed after feeder faults. The function detects the possible operations, which can be carried out by remote control. The initial information for the function is the result of the fault location explained above. The fault isolation planning isolates the located fault as soon as possible and at the same time finds switching to restore power to the first part of the feeder.

At the next step possible control actions to restore power from neighboring feeders via normally open points are analyzed. This is often called as back-feed restoration where the maximum amount of customers will be restored from other feeder(s) before repairing the fault. This analysis is taking into account all technical limitations like loading capacities of cables and voltage drops because of more loaded lines.

In this complicated analysis the centralized intelligence in control center or at the substation gives best results:

• Works dynamically in any network situation (no pre-configuration)
• Can even handle several simultaneous faults in the area
• Technical constraints can be checked in powerful analysis utilizing network and load models

The created optimal switching sequence can then be executed by the operator or even automatically in FDIR using MicroSCADA X SYS600.

Automatic Fault Isolation and Restoration (FDIR) Isolation and restoration planning can be used to produce the switching sequence for automatic fault isolation and restoration. The function speed up the service restoration especially in the case of unmanned control center.

The administrator of the system have a possibility to set automatic fault isolation and restoration functionality on. If the functionality is not switched on fault isolation and restoration is handled by operator control actions. If the automatic functionality is turned on and the fault can be definitely located to a remote controllable zone, DMS600 generates the switching sequence and runs the automatic execution by MicroSCADA X SYS600 application. Depending on settings sequence execution can be totally automatic or an operator confirmation to run the sequence may be required.

Coordinated management means that DMS600 can utilize available measurements from many locations along with distribution networks and can make optimal control decisions to keep voltages at a good level and to minimize losses in the network. These measurement points include primary and secondary substations, pole-mounted switches, and even smart meters providing real voltage in customer premises.

The objectives of Volt-VAr control are:

• Keeping voltages in limits
• Reducing losses by minimizing reactive power flows
• Reducing peak power by voltage reduction

The voltage reduction (conservation voltage reduction, CVR) is an own mode in the application. In that mode, separate voltage limit parameters are used. The control variables include capacitor bank status and voltage tap changer or regulator set-point or position. Controllable capacitor banks and transformer tap changers can be selected in settings and are easy to change. The application supports both direct control of tap positions and setting voltage set-points depending on the mode of the controller (automatic/manual). The mode can be read from SCADA process object.

The application can run without capable load flow calculation using real voltage measurements via SCADA communication. When good load flow results (afterload estimation) are available so-called pseudo-measurements can be defined to use the results from the load flow calculation.