Electronically compensated loads are revolutionizing current measurement and setting new standards in the precision of transformer testing. This innovative technology addresses the increasing demands for accuracy and flexibility in modern power engineering. By combining advanced electronic components with sophisticated compensation mechanisms, these systems enable a level of measurement accuracy that has not been possible until now. Electronically compensated burdens offer decisive advantages for both current transformers (CT) and voltage transformers (VT). They optimize test processes and increase the reliability of measurement results, thus significantly increasing efficiency in power distribution. Discover how this technology is redefining the fundamentals of electrical measurement technology and the possibilities it offers users.
Fundamentals of current measurement and transformer technology
Current measurement is the basis for the precise recording and distribution of electrical energy. Instrument transformers play a key role here by transforming high currents and voltages into measurable quantities. This transformation enables the use of standardized measuring devices and ensures the safety of operating personnel. Current and voltage transformers work according to the principle of electromagnetic induction and reduce the primary quantities to a secondary level.
The accuracy of these transformers is crucial for the quality of the entire measurement chain. Even the smallest deviations can lead to significant errors in large energy systems. Therefore, measuring transformers are subject to strict testing requirements and must be regularly calibrated. The challenge is to test the transformers under realistic conditions without endangering the stability of the grid.
Current and voltage transformers: function and significance
Current transformers (CTs) and voltage transformers (VTs) form the backbone of electrical measurement technology in power distribution networks. CTs transform high primary currents into low, measurable secondary currents, typically to 1 A, 2 A or 5 A. This allows the connection of standard measuring devices and protective equipment. VTs, on the other hand, reduce high voltages to standardized values such as 100 V, 110 V or other specified secondary voltages.
The precision of these transformers is of the utmost importance. They directly influence the accuracy of energy measurement, billing and grid stability. Modern transformers achieve accuracy classes of up to 0.1% or better. This precision must be maintained over a wide range of operating conditions, including temperature changes and load variations.
Instrument transformers are not only used for measurement, but also for protection. They isolate sensitive measuring instruments from high primary quantities, thus enabling the safe operation of complex electrical systems. The correct selection and testing of instrument transformers is therefore a critical aspect in the planning and maintenance of electrical systems.
Challenges in precise transformer testing
Testing instrument transformers presents technicians with complex challenges. One of the main difficulties lies in simulating realistic load conditions. Instrument transformers must be tested over their entire nominal range, which requires the provision of variable and precisely controllable loads. Traditional passive burdens reach their limits here, as they often only offer discrete load steps and are susceptible to temperature effects.
Another problem is the compensation of measurement errors caused by the test setup itself. Line resistances and parasitic capacitances can falsify the measurement results. These effects can be significant, especially when testing high-precision converters. The challenge is to quantify and compensate for these influences without affecting the measurement itself.
The dynamics of modern power grids, especially with the increasing use of renewable energies, also require test procedures that can map rapid load changes. Electronic compensated loads address these challenges through their ability to precisely and dynamically adjust loads and actively compensate for measurement errors.
Electronic compensated loads: an innovative solution
Electronically compensated loads represent a quantum leap in transformer testing. These innovative devices combine the advantages of traditional passive loads with the capabilities of modern power electronics. The basic principle is to electronically simulate a variable load while actively compensating for measurement errors. This enables unparalleled flexibility and precision when testing current and voltage transformers.
Unlike conventional burdens, which often offer only limited load steps, electronically compensated burdens allow the load to be adjusted continuously. This is particularly valuable for testing modern instrument transformers, which must maintain high accuracy over a wide range. Electronic compensation also evens out errors that could arise from lead resistances or thermal effects.
Another advantage is the ability to simulate dynamic load scenarios. This is crucial for testing transformers in modern power grids, which are increasingly confronted with fluctuating energy sources. Electronically compensated loads can replicate these dynamics and thus create realistic test conditions.
Operating principle of electronic current loads
Electronic current burdens such as the ESCB200 are revolutionizing the testing of current transformers (CT). The basic principle is based on the precise electronic simulation of various load scenarios. Unlike passive burdens that use fixed resistance values, the ESCB200 uses active power electronics to dynamically control the current flow. This enables stepless adjustment of the burden load over a wide range.
The ESCB200 can handle secondary currents of 1 A, 2 A and 5 A and offers a load range of up to 200 % of nominal current. This flexibility allows current transformers to be tested under a wide range of conditions, from partial load to overload situations. The electronic control ensures a high level of precision and stability of the set load.
A key feature of the ESCB200 is the active compensation of measurement errors. The system detects and corrects deviations that could arise from lead resistances or thermal effects. This contributes significantly to improving measurement accuracy. The free selectability of the load steps at 50 Hz and 60 Hz also makes the device flexible for use in different mains frequencies.
Electronic voltage burdens: ESVB200 in detail
The ESVB200 represents the pinnacle of technology in the field of electronic voltage burdens. Designed for the precise testing of voltage transformers (VT), it offers impressive versatility in terms of secondary voltages. The instrument supports a wide range of nominal voltages, including 100 V, 110 V, 115 V, 120 V, 190 V and 200 V, each also in the √3 and /3 variants. This flexibility makes the ESVB200 a universal tool for almost all common VT configurations.
The ESVB200 load range extends from 80% to 120% of nominal voltage, enabling realistic testing under various grid conditions. The electronic control allows precise and continuous adjustment of the load, enabling even the slightest deviations in the behavior of the DUT to be detected. This accuracy is particularly valuable when calibrating high-precision converters.
One outstanding feature of the ESVB200 is its ability to set and compensate for the external resistance. This enables an exact simulation of real-life load scenarios while minimizing the influence of the test setup on the measurement results. The combination of flexibility, precision and active error compensation makes the ESVB200 an indispensable tool for modern VT testing.
Technical features and performance
The technical features of the ESCB200 and ESVB200 set new standards in transformer testing. Both devices are characterized by their high flexibility and precision, which make it possible to cover a wide range of test scenarios. The ESCB200 for current transformers and the ESVB200 for voltage transformers each offer specific functions tailored to the special requirements of their fields of application.
A common feature of both systems is their ability to realize freely selectable burden levels at 50 Hz and 60 Hz. This allows precise adaptation to different grid frequencies and load conditions. The electronic compensation of resistance contributes significantly to improving measurement accuracy by minimizing sources of error that are often unavoidable with conventional burdens.
The devices feature a 6.4” monochrome display that provides a clear overview of all relevant measurement parameters. This user interface is intuitively designed and makes it easier to carry out tests efficiently. The combination of advanced electronics and well-thought-out operability makes these systems powerful tools for precision measurements in the energy sector.
Secondary currents and voltages: flexibility for various applications
The ESCB200 and ESVB200 offer impressive flexibility in terms of the secondary quantities that can be processed. The ESCB200 covers the common secondary currents of 1 A, 2 A and 5 A, making it suitable for almost all standard applications in current transformer test. This versatility makes it possible to test various types of current transformers with a single device, which significantly increases efficiency in test laboratories and during field measurements.
The ESVB200 goes one step further in terms of flexibility. It supports a wide range of secondary voltages, including 100 V, 110 V, 115 V, 120 V, 190 V and 200 V, each also in the √3 and /3 variants. This comprehensive coverage makes the ESVB200 a universal tool for testing voltage transformers. Whether dealing with standard VT applications or special applications, the device can adapt to the respective requirements.
The option of selecting between different secondary quantities allows users to test a wide range of transformers with the highest precision. This is particularly valuable in environments where various transformer types are used, such as in large substations or energy distribution centers.
Load ranges and precision
The load ranges of the ESCB200 and ESVB200 are carefully designed to simulate realistic operating conditions for instrument transformers. The ESCB200 offers an impressive load range of up to 200% of nominal current. This not only allows testing under normal conditions, but also simulating overload situations, which is crucial for testing the performance and safety of current instrument transformers.
The ESVB200 covers a load range from 80% to 120% of nominal voltage. This range is ideal for investigating the behavior of voltage transformers under various grid conditions, from undervoltage to slight overvoltages. The ability to set these load ranges precisely and continuously enables a detailed analysis of the transformer behavior over the entire relevant operating range.
The precision of both devices is remarkable. Electronic compensation and the option to adjust the external resistance minimize measurement errors. This results in the accuracy required for calibrating and testing high-precision converters. The ESCB200 and ESVB200 achieve accuracy classes that meet the strictest requirements of energy measurement technology.
The combination of wide load ranges and high precision makes these devices indispensable tools for laboratories, utilities and testing service providers. They not only enable standardized tests to be carried out, but also limit and special case investigations to be made, which is invaluable for the development and validation of modern instrument transformers.
Main features and applications
The ESCB200 and ESVB200 are characterized by their diverse main functions, which make them indispensable tools in the field of instrument transformer testing. A central function of both devices is to provide an accurate load during the test. This makes it possible to test the test object under realistic conditions and to analyze its behavior under different load scenarios.
The devices offer the option of loading the test object with the corresponding load level in relation to its nominal load. This capability is crucial for assessing the performance and accuracy of instrument transformers under different operating conditions. The ability to freely select the load levels at 50 Hz and 60 Hz makes it possible to perform tests for different grid frequencies, which in turn makes the devices internationally applicable.
Another key feature is its suitability for both manual and automatic test procedures. This increases flexibility of use and enables routine tests and complex measurement series to be carried out efficiently. The combination of these functions makes the ESCB200 and ESVB200 versatile instruments that can be used in various fields of power engineering.
Testing current transformers (CT)
The ESCB200 is specifically designed for testing current transformers (CT). Its primary function is to provide a precise and variable load for the secondary circuit of the current transformer. This allows for an accurate assessment of the transformer’s transfer characteristics under various load conditions. The ability to simulate loads up to 200% of nominal current is particularly valuable for investigating the behavior of CTs under overload conditions.
A key aspect of CT testing with the ESCB200 is the ability to determine the ratio error and phase error of the transformer. These parameters are crucial for the accuracy of the current measurement and, consequently, for correct energy metering and grid control. Electronic compensation of the resistance helps to minimize measurement errors, thus enabling highly accurate determination of these critical characteristics.
The ESCB200 supports both routine testing and detailed analysis of transformer behavior across the entire load range. This makes it an indispensable tool not only for manufacturers of current transformers, but also for energy suppliers, testing laboratories and maintenance teams. The ability to perform automated test sequences increases efficiency when testing large series of transformers, while ensuring a high level of consistency in measurement results.
Testing voltage transformers (VT)
The ESVB200 is the equivalent of the ESCB200 for voltage transformer (VT) testing. Its main task is to provide a precisely controllable load for the secondary circuit of voltage transformers. This enables a precise examination of the transmission behavior of VTs under different load conditions. The load range of 80 % to 120 % of nominal voltage makes it possible to analyze the behavior of the transformers at both undervoltage and overvoltage.
A key aspect of VT testing with the ESVB200 is the determination of the voltage ratio error and the phase error. These parameters are crucial for the accuracy of the voltage measurement and thus for the quality of energy distribution and billing. The ESVB200’s ability to set and compensate for the external resistance goes a long way towards minimizing measurement errors and enables highly accurate determination of these critical values.
The ESVB200 supports a wide range of secondary voltages, making it a versatile tool for testing different types of VT. This is especially valuable in environments where different voltage levels and transformer configurations are used. The ability to perform both manual and automated tests makes the ESVB200 an efficient tool for manufacturers, utilities and test laboratories. It not only enables routine testing, but also detailed analysis of transformer behavior over the entire relevant voltage range.
User-selectable burden steps at different frequencies
A key feature of the ESCB200 and ESVB200 is the ability to implement freely selectable burden steps at 50 Hz and 60 Hz. This function offers unparalleled flexibility when testing instrument transformers. The ability to precisely match burden steps to the specific requirements of different transformer types and network frequencies is a decisive advantage over conventional test instruments with fixed burden steps.
Support for both 50 Hz and 60 Hz makes the devices internationally applicable. This is particularly valuable for manufacturers and test laboratories that produce or test instrument transformers for different markets. The stepless adjustability of the burden also enables a detailed analysis of the transformer behavior over the entire relevant load range.
This flexibility in load selection makes it possible to simulate various grid scenarios and to examine the behavior of the measuring transformers under realistic conditions. This is particularly important in modern power grids, which are increasingly confronted with fluctuating loads and decentralized energy supply. The ability to simulate these dynamic conditions makes the ESCB200 and ESVB200 indispensable tools for the development and validation of modern instrument transformers.
Adjustable external resistance and resistance compensation
The ability to set and compensate the external resistance is a key advantage of the ESCB200 and ESVB200. This feature addresses one of the biggest challenges in transformer testing: the influence of the test setup on the measurement results. By setting the external resistance, realistic load scenarios can be precisely simulated, which significantly improves the accuracy and informative value of the tests.
Resistance compensation goes one step further by actively compensating for measurement errors that could arise from lead resistances or other parasitic effects in the test setup. This is particularly important when testing high-precision transducers, where even the smallest deviations can be significant. Compensation makes it possible to accurately determine the intrinsic properties of the DUT without them being distorted by influences from the test setup.
This advanced function of resistance setting and compensation significantly improves measurement accuracy. It makes it possible to detect and quantify even the smallest deviations in the behavior of the measuring transducers. This is not only of great importance for quality assurance, but also for the development and optimization of new transducer types.
In practice, this means that users of the ESCB200 and ESVB200 can achieve more precise and reliable measurement results. The ability to minimize the influence of external factors increases confidence in the measurement data and supports informed decisions regarding the performance and usability of instrument transformers. This is particularly valuable in critical applications, such as in high-voltage networks or in the billing of large amounts of energy.
Integration possibilities in smart grid systems
The integration of electronically compensated burdens such as the ESCB200 and ESVB200 in smart grid systems opens up fascinating possibilities for the future of energy measurement technology. In intelligent power grids, precise measurements play a key role in the efficient control and monitoring of energy flow. The ability of these devices to perform highly accurate tests could be integrated directly into the grid infrastructure.
One possible development is the implementation of continuous online testing of instrument transformers during ongoing network operations. In this case, the electronically compensated burdens could function as permanent monitoring systems that check the performance and accuracy of the transformers in real time. This would enable proactive detection of deviations or signs of aging before they reach critical levels.
Integration into smart grid systems could also provide the ability to collect and analyze test data centrally. This would enable a comprehensive overview of the condition and performance of all instrument transformers in the grid. Such data could be used to optimize maintenance intervals, improve grid stability and plan infrastructure investments over the long term.
Furthermore, future versions of these devices could be equipped with advanced communication capabilities to interact seamlessly with other smart grid components. This would enable the measurement accuracy and frequency to be dynamically adapted to current grid conditions, thus helping to improve the overall efficiency of the energy system.
Conclusion: the importance of electronically compensated burdens for modern energy technology
Electronically compensated burdens such as the ESCB200 and ESVB200 have become established as a key technology in modern power engineering. Their ability to perform precise and flexible tests on current and voltage transformers is invaluable for ensuring accuracy and reliability in energy measurement and distribution. These devices address the increasing demands for measurement accuracy and flexibility at a time when the complexity of power grids is continuously increasing.
Special features such as freely selectable burden steps, adjustable external resistance and active resistance compensation enable a previously unattainable level of precision in transformer testing. This is particularly important in view of the increasing integration of renewable energies and the associated challenges for grid stability. The ability to simulate realistic load scenarios and to replicate dynamic grid conditions makes these devices indispensable tools for the development and maintenance of modern energy infrastructures.
The versatility of the ESCB200 and ESVB200 in terms of manual and automatic test procedures, as well as their adaptability to different frequencies and load ranges, underlines their importance for a wide range of users. From manufacturers to energy suppliers, as well as testing laboratories and maintenance teams, everyone benefits from the increased efficiency and reliability offered by this technology.
In summary, electronically compensated loads such as the ESCB200 and ESVB200 play a key role in ensuring measurement accuracy and thus the efficiency and reliability of modern energy systems. Their importance will continue to grow in the future, as they provide a crucial bridge between precise measurement technology and the requirements of intelligent, dynamic power grids.