Recording devices during emergency processes in electrical networks

The analysis of the operation of sections of the power system, the making of calculations, the preparation of construction projects or the technical re-equipment of power supply facilities are carried out using equivalent equivalent circuits. Most of the characteristics of the equipment elements in the calculations are taken from reference books, while the actual characteristics are slightly different, as they depend on environmental factors, mechanical and chemical influences, interaction with other equipment elements. Also, the reason for the discrepancy between the declared characteristics can be errors in the dimensions of the structural elements of the equipment, changes in the materials from which these parts are made.

In general, we can conclude that the use of reference data in calculations does not allow to obtain high accuracy of calculations, often such calculations do not allow to take into account all possible nuances in the electrical network, and in the future, for example, after technical re-equipment of the substation, occur severe emergency modes of operation of the electrical network, which may lead to undesirable consequences.

This problem can be solved by recorders of emergency processes, which control real processes taking place in electrical networks. The data obtained with the help of these devices make it possible to carry out the necessary calculations with maximum accuracy, to correctly select the operating modes and settings of the relay protection devices and the automation of the equipment.

Also, a very important advantage of the emergency process recorders can be considered that the data of electrical network failures obtained by the emergency process recorders is used by power engineers to restore the picture of what happened.

Accurate data on the nature and location of the fault can greatly simplify the work of field crews performing restoration work on damaged power lines.

The ability to determine the distance to the fault location is very important for long high voltage lines. For example, searching for a fault on a 110 kV line 60-80 km long may take more than one shift of the repair team. And if, for example, there is an overlap of the insulation, then such damage is quite difficult to detect without knowing the clear boundaries of a possible damaged area.And if we take into account that the 110 kV line can be quite important in the operation of the power system, then we can conclude that this method of searching for faults on the line is not relevant, that is, in this case, the recorder of emergency processes is indispensable.

In the case of availability of the data from the emergency process recorder, the nature of the failure can be precisely determined. For example, the recorder indicates that a single-phase earth fault has occurred at a distance of 43.3 km from the substation where this recorder is installed. With this data in mind, the repair team purposefully travels to that section of the line and looks for damage that would be characteristic of a short circuit of one of the power lines' phases to ground.

The data of the recorders of emergency processes is quite accurate, therefore, the search for damage by the repair team, as a rule, is carried out quite quickly.

Below is a description, functionality of emergency process recorders that are used in electrical networks.

A digital emergency process recorder is used to record various processes that occur in the power system. In the normal operation of the electrical network, this recorder allows you to perform various measurements of electrical quantities in certain units of time and, based on the data obtained, to perform various calculations and studies…. This device allows you to measure the following electrical parameters, both in normal and in emergency mode of operation of the electrical network:

• linear, phase voltage values, zero sequence voltage;

• phase, line currents, their direction, zero sequence current;

• active and reactive components of the power flowing along the lines, their direction;

• the frequency of the power grid.

In the event of a short circuit (breakdown) of one of the power lines of the substation, the recording device records the exact time, the above electrical parameters at the time of the breakdown, determines the nature of the breakdown, indicates the distance to the damaged part of the line.

A significant advantage of this device is the ability to determine the location of the fault and record the electrical parameters during the fault on lines with one or more taps. In this case, the recording device takes into account all possible interactions between sections of the electrical network and shows the possible variants of the emergency situation that has occurred. Based on the analysis of the data received from the recording devices installed in neighboring substations, it is possible to accurately reconstruct the picture of what happened.

A PARMA logger has an internal memory in which all logged processes are recorded. This device is connected to the ASDTU, SCADA, APCS systems, which allows you to transfer recorded data, remote control of the device, read the necessary data, electrical parameters in real time.

The recorders have a number of advantages, which are the safety of service by personnel, ease of operation and wide functionality, high noise resistance, low error when measuring electrical quantities, distances to the places of damage and the time of the processes.

Emergency process recorders have the option to extend the standard functionality by installing additional software.Additional programs simplify the process of recording waveforms, saving, organizing and transferring recorded event files.

Due to the many indisputable advantages, emergency recorders are widely used in power facilities of power systems of Russia, Kazakhstan, Ukraine, Belarus.