Tasks and goals:​

  • Real time situational awareness

  • On-line parameters monitoring (including Frequency and Voltage)

  • Post event analysis

  • Oscillation detection and monitoring

  • Power flow monitoring

  • Islanding detection

APDC - Advanced Phasor Data Concentrator

APDC (Advanced Phasor Data Concentrator) – is the high-performance, flexible and widely scalable platform for creating both relatively simple systems of power facility level and complex multi-level distributed WAMS (Super PDC Network) at power plants, substations and regions (controlled

by united dispatcher centers).

Software APDC is designed for creating both relatively simple systems of power facility level and complex multi-level distributed WAMS / WACS / WAPS (Wide Area Monitoring / Control / Protection System) at power plants, substations and regions.

In PJSC “SO UPS” (System Operator of United Power System) the system of Automatic Acquisition of Information from SMPR sensors is created, based on these solutions, and is functioning in industrial operation. AAI SMPR provides data collection from more than 400 SMPR sensors, established on more than 70 power facilities of UPS.

APDC is installed and is working on major power stations of Russian Federation.



APDC has been developed as a Web-based application. Big data technologies, M2M and high performance distributed calculations have been used as well. That provides possibilities to implement APDC with state-of-art IT infrastructure. APDC supports mobile platforms, virtual data storages, and cloud-based solutions (IaaS).

Developed with HTML 5, WebGL and JavaScript support
No setup procedures – easy to use and support
Ready to use on any device with modern Internet browser
In-built constructor of Display forms
Single-Line Diagram electrical schemes constructor

(IEC 61970-453 CIM Based Graphics Exchange compatible)
IEC 61968 and IEC 61970 compatible power system database model

Graphical User Interface


Real time and historical storage

Real time and historical data are processed

by the same database management system

Very low latencies

(8 ms for PDC hop)

High performance (sample rate is 50-200 measurements per second for one parameter)

Fast search through historical data

Failover solution

(cluster from 2 up to hundreds of nodes)


(data distribution between all cluster servers)


Data source and data exchange adapters

Data source adapters:
  • C37.118-2011/2008 (client)

  • IEC 60870-5-104 (client)

  • Data exchange of COMTRADE and CSV (files) by FTP

  • IEC 61850 (client)

  • OPC (client)

  • Modbus (client)

Distributed data exchange (PDC-to-PDC):
  • C37.118-2011 (server)

  • Real time data exchange based on UDP (unicast, multicast) with low latency

  • Web-services to provide data on demand


APDC solution provides an implementation of distributed multi-tier WAMS/WACS/WAPS that covers both PMU’s and Control Center’s network.

In this case:

  • All data is distributable

  • Historical data is given to user on demand automatically

  • Real time data is given to user automatically by subscription

Power system models database

Conductive equipment models storage

(single-line bus-bar electric schemes)

Grid models may be used to make the calculations

(database contains topology information, system links, equipment characteristics) and visualization

Measurement model provides the links between tags and grid elements

Model is CIM compatible

(CIM/XML import support)

IEC 61970-453 (CIM Based Graphics Exchange) compatible schemes storage


Low frequency oscillation monitoring

Low-frequency oscillations in power systems are inherently non-linear and non-stationary processes representing a superposition of numerous rotating masses movement components having mutual influence in a power region or power center.

In the case of significant power imbalance periodic low-frequency oscillations of frequency with a magnitude exceeding 0.05 Hz may arise in the power systems.

These situations imply the crucial role of monitoring each generator damping capability that is determined by the adjustment of the system regulators
in use.

APDC provides:

  • Online monitoring for oscillations

  • Oscillations parameters detection – magnitude, frequency, damping

  • Finding steady conditions of power systems

  • Danger oscillations detection (poor damped)

  • Finding oscillations groups (in-phase, anti-phase)

  • Assessment of generators role (damping or amplifications)

  • Monitoring of generators’ excitation system faults

  • Spectral analysis

  • Permanent modes search

  • Historical oscillations analysis


Spectral Analysis

Spectrogram is a special tool that allows representing spectrum of signal in the historical perspective. By pointing to the interesting time and frequency, one can see spectrum for all frequencies at the whole time interval along with amplitudes (amplitude differences are displayed with the help of color gradient).

Spectral analysis allows user to estimate spectrum visually and find potential modes. In the picture on the right one can notice potential modes of 0.6 Hz and 1.2 Hz.


Historical oscillations analysis


As a further development of oscillation detection system, APDC provides Historical oscillations analysis tool. This tool allows examining non-linear and non-stationary nature of oscillations. Parameters for nonlinear oscillations (Frequency, amplitude, phase, damping) are calculated throughout the whole process.

This tool also calculates the phases of modes and groups them into sin-phase and anti-phase collections.

Modes are automatically correlated and classified by scope (cross-generator, local or inter-area for WAMS Systems) and by danger levels, which can be defined by user in advance through settings.


Permanent modes

Permanent modes analyzer is a tool for detecting low amplitude modes, which are constantly presented in energy system. This tool allows processing large amounts of data – hours, days, weeks, months.

It is necessary because those modes are indistinguishable on small time intervals where they are suppressed by signal noise.

For example, one mode always appears when a power plant starts working in the morning and disappears in the evening when its engines are switched off.


Synchronous oscillations of active power monitoring

As a further development of oscillation detection system (especially with high amplitude), APDC provides tools for

real-time monitoring of power flows in controlled sections.
This tool contains several window forms with complex representation of controlled
sections and monitored parameters.

Those forms include:

  • controlled section single-line electrical scheme

  • 2D graphics

  • power flow gauge

  • navigation buttons


As an overview, the main window is a Dashboard. It contains a list of controlled sections (designed as navigation buttons), power flow gauge with defined limits, column of oscillations amplitude and
a column of oscillations danger level (designed as a color-changing circle from green to red for different danger levels).
The lower part of the window represent
2D graphics of oscillation amplitude and frequency in each controlled section.

When the event occurs and danger level oscillations happen in certain controlled section, user can navigate to its window form. Detailed window form contains single-line diagram electrical scheme, power flow amplitudes in each line of controlled section as well as total power flow gauge with defined limits.
In the case of necessity user can also view detailed form with 2D graphics of Frequency, Voltage, Active power flow and oscillation’s Amplitude


Islanding visualization

Geographic map layer can visualize islanding in case of such a situation. As an example, there are pictures representing system splitting into two asynchronous regions.

Weak connection between south and north subregions gets broken and two groups of power stations are formed that have their voltage vectors rotating independently.

This can be seen from vectors on a map and from vectors on the radar diagram.


Voltage monitoring

One of the main application of WAMS systems is voltage monitoring. APDC provides a flexible platform to combine different visual controls on one window form.

Geographic map layer is usually used as the lowest level.
User can add gradient fill of the territory by voltage level (red and blue gradient “islands” for high and low voltage regions respectively).

Another level is layer of gauges and histograms. Output of voltage values
and voltage vectors can be put as nodes on the map, and histogram
of voltage levels in the lower part of the picture can be normalized
to see voltage drop in percentages of nominal value.
For a long-time seeing, voltage trends can be added on the map as another layer to help user to see voltage changing in period of time. User defines the width of the time interval that fits his tasks better.

Other visual controls are power flow gauges of the main power plants. When voltage drops, it usually results in generators’ shutdown and corresponding active power flow drop, which is also useful to monitor.


Power flows control

When it comes to the power flows control, APDC can provide the best solutions to create and monitor the critical control sections.

User can define the power plants on the map and “build” connections between them as in real life. Those connections can represent actual power flow in control sections and defined limits can provide user the information about forthcoming to MPF (maximum power flow) and EPF (emergency power flow) well before the critical situation.

This can help a dispatcher to act in good time and to avoid emergency situations that can lead to customers disconnection and equipment damage.

User can also add to the map other visual controls like relative angle radar diagram or other different charts. User, of course, can define gradient fill for power flow, voltage vectors in power station nodes and power flow direction.

At last, APDC can automatically alarm user when power flow reaches dangerous levels. Those notifications are not only displayed in the interface, but also can be sent to users e-mail box.


Equipment monitoring and analysis

The synchronous generators are designed to operate under balanced load conditions, when the phase currents are equal or close to each other.
However, there are several causes that may ruin this stability:

• unbalanced consumption (for example, railways or metallurgy furnaces)
• internal unbalance causes (like isolation deterioration, stator-rotor air gap nonuniformity or magnetic circuit faults)
• unbalanced operation (might be driven by the open-phase conditions of the power transmission lines or within substations, in case of single-phase circuit breakers failures etc.)
The unbalanced operation may lead to the undesirable consequences:

• increased power losses
• heating of the damping winding or the rotor (leads to isolation abrasion and deterioration)

signification mechanical vibrations driven by the fluctuating toque resulting from the negative sequence magnetic field (leads to windings deformation and/or displacement)

• voltage and current asymmetry

• current harmonics distortion

APDC provides various online monitoring and statistical analysis of:

• stator voltage as a function of frequency U (f)

• active and reactive power (on P-Q diagram)

• unbalanced operation

For P-Q diagram user can define borders of nominal mode for generator`s active and reactive power and borders of warming zone. In real-time APDC alarms user when the parameters leave the borders of nominal mode and/or warming zone.


In addition, it is possible to calculate statistics for generator working in different modes for a certain period of time. Statistics are presented as a report, including 2D graphics, tables and P-Q diagrams.


Monitoring of Automatic Excitation Regulators

Due to peculiarities of electricity production and transmission technologies high attention is paid to the questions of automatic regulation of voltage and reactive power. It is not only technical, but also an economic necessity.


Application of Automatic excitation regulators (AER) solves the problems

of stabilization for electrical parameters of energy system, what is very

important for high-quality electricity supply for consumers.

Though AER is widely used in emergency situations in energy system for providing static and dynamic stability of generators, AER itself can have technical malfunctions that should be monitored:

• absence of stabilizing channels blocking in situation of edgy power deficit

  or excess in energy system;
• absence or untimely input of excitation relay boost;
• untimely withdrawal of excitation boost;
• inappropriate working of minimal excitation limiter;
• inappropriate working of double excitation current limiter.

APDC provides user with Automatic Excitation Regulators Monitoring tool, that allows to calculate parameters changing and control excitation systems

in real-time. This, in its turn, helps to identify AER malfunctions early and put it out for maintenance

or repair, which leads to economic losses fall without possible emergencies. For deeper analysis, APDC provides off-line tool for conducting experiments with different settings on the same synchronized vector measurements. This helps user to simulate possible equipment reactionsand distinguish AER equipment malfunction without emergency situations.



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