New generation of Tavrida Electric User Software – TELUS 3.0.

V.Ossipov - Product Specialist of Tavrida Electric Export

Abstract Tavrida Electric (TEL) has developed a new generation of Tavrida Electric User Software - TELUS 3.0. This new version of TELUS contains such features as Network editor, Fault location, Autocoordination, Autocorrection, Simulation, etc. This paper describes the basic features of the TELUS 3.0.

Introduction The Tavrida Electric User Software (TELUS) system provides configuration and control of the MPM (Main Processing Module) of recloser Control cubicle features and functionality. Compared to the previous version, this new version of TELUS has been fundamentally updated to help TELUS users solve the following problems:

• Complexity of protection setting development.

Usually the development of protection device settings is a multi-stage complex process that demands a significant amount of highly skilled specialist’s time. What Tavrida Electric wants to introduce is a highly automated process that does not require special skills to calculate special modes of the network, fault modes, etc.

• Testing of the operation of microprocessor relays in a real network situations is usually impossible.

Tavrida Electric has concentrated on pre-installation testing of protection devices

with the entire system of protection elements and their settings. This means that TEL has made it possible to test the virtual (software) model of a protection device with settings that have been chosen, in any network fault situation.

• Fault location problem

Up to 50% of the time required to restore normal power delivery in case of a fault in a distribution network is time required to find the fault. With our new generation of Reclosers with RC-02 control cubicles and TELUS user software this time can be reduced to an absolute minimum.

• Complexity of in-field device setting writing and log reading

The process of sending-receiving device settings and logs was made as simple as possible. Actually now these processes are nearly transparent to the user.

Network editor The protection settings automatic calculating algorithms are included in the new version of the Tavrida Electric user software – TELUS 3.0. The user is provided with a special visual-style editor (Network editor), which allows him to draw feeder schematics (Fig. 1) and specify the

protection setting

calculating criteria.

The Network

editor window

consists of the toolbar in the top part of the window and the main

Fig. 1 Network editor window (example)

area for visual editing of the feeder diagram. The diagram can be adjusted at any time by selecting one or several objects (sources, wires, poles, loads, fuses, capacitor banks, cables, step-up transformers) with the mouse and dragging them to any desired location. All links and lines between objects change their direction automatically.

The user can put an object on the diagram by selecting the corresponding toolbar button and clicking with the mouse on the diagram. After an object is placed on the diagram, it has the default values of all properties. The user is allowed to edit the values of any setting of any object.

Protection settings After these schematics are ready, the user can start using the capability of automated setting generation.

The settings of all protection elements of all reclosers installed on the feeder can be found in the Protection branch of the feeder. Protection settings are stored as 4 independent groups of settings (Fig. 2).

Any time one of the 4 groups is set as active, others do not take part in the protection. Any

group can be selected as active either locally (with the recloser control module MMI panel) or remotely (with the SCADA system or remote TELUS).

The settings of the group with the same number as all reclosers of that feeder can be viewed or edited in a single window. Group of protection settings window consists of the 2 parts: Autocoordination frame and Protection frame. (Fig. 3)

Protection settings can be set-up under three different modes: Independent, Autocoordination and Autocorrection.

In the Independent mode, all settings of all protection elements become fully editable without restriction. Tests are automatically performed and each value is checked to assure that it fits into the valid range consistant with each type of setting.

Autocoordination and Autocorrection modes allow the set-up of protection settings of all reclosers automatically or semi-automatically.

In the Autocoordination mode, it is only required to specify the settings of automated protection coordination between reclosers and

Fig. 2 Recloser settings window

Fig. 3 Protection settings window (Autocoordination frame).

some criteria for the protection on the particular feeder.

The settings which the autocoordination algorithm has calculated become non-editable and are marked with the blue labels.

Some settings cannot be calculated automatically, as they are normally a matter of preference, and rules of the particular distribution network. They include the settings of the “extremely quick” OC3 (Overcurrent), EF3 (Earth fault) elements, UF (Underfrequency) element, settings of auto-reclose elements (AR OC/EF, AR SEF, AR UV and AR UF) and live-line maintenance supporting elements (OCLL, EFLL).

In the Autocorrection mode, the user can edit almost all settings, but the autocoordination algorithm will be called automatically for the following:

• the input will be checked to satisfy the valid range for the setting edited;

• some settings of the same recloser and of other reclosers will possibly be automatically adjusted to leave the rules of protection coordination and zone reservation valid.

Settings which were automatically adjusted get a yellow background.

In both the Autocoordination and the Autocorrection modes, auto-reclose settings of only one recloser are editable: the algorithm calls the auto-reclose elements of all reclosers on a feeder to have equal settings.

If, during the editing (with either Independent, Autocoordination or Autocorrection mode), some value was set, which is not compatible with some other values of settings, the incompatible settings are marked with red; the protection settings group (if this group of settings is marked as In use) in this case cannot be marked as Ready.

A new type of flexible time-current characteristic (TCC) has been designed to support the autocoordination algorithm. This characteristic (named TEL A - “TEL Automatic”) is supported by the new generation of Tavrida Electric recloser control cubicles (RC02). It delivers

minimum possible tripping times if TCC’s for

downstream devices as well as time and current grades are known (Fig.4 ).

The time-current characteristics of the slow, fast and sensitive elements of the overcurrent

and the earth-fault protections are then automatically calculated almost immediately.

Simulation When the schematic (or diagram) of a particular feeder is ready and some protection settings are selected (either automatically or manually), it is

Fig. 4 Set of slow phase current TTC’s for reclosers 1-4 calculated with the aid of the autocoordination algorithm for the feeder

pictured in Fig. 1

Fig. 5 Phase A, B and C currents seen by R3 (Fig. 1) during

clearance of sustained downstream earth fault.

quite easy to see how the reclosers will act in case of a fault. The user just selects the duration of simulation, clicks the “Simulation” button and the entire fault scenario is there: the user can see currents, voltages, reclosers’ event logs, etc (Fig. 5).

After running a simulation, the dynamic behavior of all devices (fuses and reclosers) for the particular fault is calculated. By setting different fault types at different locations, one can test the correctness of recloser operation.

Fault location Distance protection deals with a limited number of simplified fault types. In reality, a short circuit fault represents a dynamically changed set of six non-zero conductivities (Fig. 6).

This assumption may result in substantial errors, especially with fault evolution during its life.

Tavrida Electric has developed a new algorithm that is based on the general representation of the fault and is free of this disadvantage.

After one or several reclosers on the feeder “see” the fault currents or voltages, the recloser which is closest to the fault tries to struggle with it by means of autoreclose cycles. If it fails, it comes to the “lockout” state and sends the results of its last measurements to the Control Room. The TELUS software system predicts the possible location of the fault and displays it on the feeder

diagram, along with the predicted values of contact resistances in all phases.

Let’s put the fault for example between A and B-phase with a 1 Ohm resistance and see how the fault could be identified by a Fault Location algorithm. The algorithm sees 2 possible places for a fault (Fig. 7), because for recloser R2 these 2 branches are equivalent, and it physically cannot discriminate between these 2 places for the fault. If the recloser is close to the fault, it is not a big problem. In the worst case it still does not need to search for the fault across the entire feeder, but just check 2 places.

The tests show that under real-world conditions, due to feeder loading fluctuations, measurement errors and temperature changes, the worst error in finding the fault location is 1 to 2 kilometers. These results were obtained on feeders with a backbone length of about 100 km. This system is very good for fault isolation in distribution systems that have wide load fluctuations and complex feeder schematics (like in transmission line systems where such algorithms are quite common already).

This feature allows sending the mobile linesmen to the known segment of 1 or 2 kilometers length to fix the fault, which type is also already known. This, instead of searching for an unknown fault across the entire 100-kilometer feeder with all its branches. In the case of normal temperature and

Fig. 6 Non-zero conductivities

determine fault type.

Fig. 7 Determination of fault location

normal load, the length of a possible fault region diminishes to a few dozen meters.

User-defined Signals editor (UDDG) The Tavrida Electric RC02 generation of recloser control boxes supports generation of special signals. Another graphical editor for that purposes exists in TELUS. It allows (easily – just with your mouse) the drawing of the schematic of a special signal to be generated by the RC.

For example, a simple circuit is shown (Fig. 8) which generates an alarm signal when the current in either of 3 phases exceeds the level of 50 Amps.

This signal can be assigned to be outputted either though the SCADA system, through the I/O modules, or both. Alternatively this signal can be ordered to be stored in one of the recloser logs.

Conclusions So, all the above stated problems can be solved with the aid of this new generation of Tavrida Electric User software, that provides the following possibilities:

• Enter the schematic of any feeder

• Automatic calculation of recloser protection settings with “by hand” correction possibility

• Electronic (software) simulation of different fault types

• Quite precise determination of fault location

• Simple procedure of composingspecial signals to be generated by the RC

References 1. Chaly, K. Gutnik, A. Testoedov, A.

Astrakhantsev, “Autocoordination of protection settings of series reclosers”. Tavrida Electric, Moscow, Russia, Marshala Birjuzova str, 1.

2. TELUS 03.01.00E User Guide

Fig. 8 UDDG editor window.