Wide Area Measurement Systems (WAMS)

One of the lines of technological development of power systems in the world, which provide increasing of capacity and stability of power transmission lines, is creation and implementation of WAMS (Wide Area Measurement System).

WAMS systems provide time synchronized measurements of the parameters, which characterize the power system state in its various points with high resolution. This data level enables:

• To observe transient states;
• To estimate the current states of entire power system;
• Effectively to analyze the causes and consequences of technological derangements and power system disturbances;
• To verify and specify the dynamic model of a power supply system;
• To fine-adjust the emergency and protective automation.

All aforesaid allows to raise the level of information support of dispatching control that will provide the improvement of management of state of power system and its general work efficiency.

The equipment and the software of WAMS Systems

Measurements in WAMS systems are implemented by special-purpose equipment – PMU which determines phase angles and amplitudes of currents and voltages, frequency, power etc. in various parts of a power supply system. All measurements are synchronized by means of GPS accurate within 1 micro second.

Data from PMU with time stamps are transferred to WAMS systems server on which the special software is installed, which provides data acquisition from all PMU`s in system and makes their processing, calculations, storage, and also, displays in real-time power system state parameters and delivery of messages and signals.

Functions and opportunities of application of WAMS systems

General functions of WAMS systems:

• Implementation of the synchronized measurements of the parameters, which characterize current power system state in various sections, acquisition, processing and storage of this data, representation of the information to dispatchers of a power system;
• Calculation of a current power system state parameters in real-time mode;
• Control of parameters of power system stability in real-time mode (detection of fluctuations of frequency, power, a differences of angles, etc.);
• Alarms and warnings delivery to dispatchers and SCADA systems in case of detection of deviations from the preset parameters of a power system;
• Data for post emergency analysis of power system disturbances;
• Data exchange with SCADA systems and other WAMS systems.

Advantages of practical integration and use of WAMS systems

• Reliability enhancement of work of a wer system by minimization of risks of occurrence and growing of system disturbances and decrease of time of switching-off that will considerably lower losses;
• Increase volume of power transferred through existing lines;
• The maximal effective use of existing resources of a power system;
• Increase of operational efficiency of entire power system.

Additional possibilities of WAMS system of PARMA, Ltd. PMU devices Model 1133А Power Sentinel and software WAProtectorTM, which applied in WAMS systems of "PARMA" Ltd. in addition to the aforesaid functions of WAMS systems allow also to implement:

• Control of the electric power quality parameters: flicker, THD, RMS, K-factor etc.;
• Standard energy revenue metering with an accuracy up to 0,025 % in the conditions of energetic’s object when currents, voltage and frequency are considerably changed, burden has active-reactive character, the equipment is exposed to influences of electromagnetic interferences (provided that instrument transformers will be calibrated);
• Direct measurement of wire temperature of overhead transmission lines.

Thus, integration of WAMS systems proposed by PARMA, Ltd. in a power system will provide dispatchers with great amount of information on dynamic properties of a power system, afford an opportunity timely and precisely to estimate power system state and to carry out necessary actions on accident prevention or to prevent their growing in the large system disturbances.

Result of work with the data from integrated WAMS systems will be:

• The growth of operational reliability of the entire power system;
• As full as possible usage of resources of the existing equipment;
• More precisely setting of emergency automation;
• Monitoring of stability and temperature of overhead transmission lines;
• Control of PQ parameters and standard energy metering.

Experience of "PARMA", Ltd. in practical integration of WAMS systems shows that at relatively small expenses and in shot period of time can be constructed full-function WAMS system of world competitive level with flexibly adjusted to needs of each Customer functions. If the large power system include in the structure some of regional power systems, it is possible stepwise to develop WAMS systems in separate regions (power systems). Thus the data from regional WAMS systems can be in full amount accessible in the dispatching center of entire power system.