KoCoS Blog

The European power grid dealt with major problems on 08 January 2021. An entire region in Eastern Europe was disconnected, and in some cases experienced power outages. The European power grid is part of the critical infrastructure (CRITIS). The Austrian Federal Army had already warned in January 2020: "A Europe-wide blackout is to be expected within the next 5 years!“
On 8 January 2021 at around 14:05, a frequency deviation of around 250 mHz occurred in the synchronized European high-voltage electricity grid. As a result, the region of south-eastern Europe was disconnected from the European interconnected grid.

A cascade of failures of equipment, such as power lines and switchgear in south-eastern Europe, led to massive problems within the European power grid. According to the report, the near-blackout in large parts of Europe was triggered by a transformer station in Ernestinovo, Croatia. Initial investigations stated at 14:04 an overcurrent protection device on a 400-kilovolt bus bar coupler in the substation tripped, causing it to switch off automatically. This also interrupted two extra-high voltage connections that carry electricity from the Balkans to other parts of Europe; affecting the lines to Žerjavinec (Croatia) and Pecs (Hungary) in the north-western direction. The result was that within less than 50 seconds the European power grid split into two areas: the northwest, which lacked 6.3 GW of generation capacity, and the southeast, which had a corresponding surplus.

In some regions there were visible problems. For example, lamps in households and on the streets have lit up or went out, and electrical appliances turned on and off. The radio station RFI România reported power cuts in parts of Romania. The frequency drop led to consequential disturbances at various infrastructure operators, such as the Vienna airport and hospitals, which triggered the emergency power supply. There was also a serious incident at Vienna Airport, where hundreds of hardware parts were destroyed and damage amounting to several hundred thousand euros was caused. Approximately one hour after the disconnection, the two power grids were resynchronized.

Exact sequence of the disturbance
At 14:05 (CET) the frequency in the north-western power unit dropped to 49.74 Hz. After about 15 seconds, it stabilized at 49.84 Hz, which is still within the permissible band for deviations of plusminus 0.2 Hz. At the same time, the frequency in the south-eastern area jumped to 50.6 Hertz before stabilizing at a value between 50.2 and 50.3 Hz.

The disconnection of the sub-grid had a clear impact on the grid frequency. Thus, at (14:04:55 local time CET), the grid frequency dropped from about 50.027 Hz to a minimum of 49.742 Hz within 14 seconds. This left the normal control range of 50.000 Hz ±200 mHz. The first stage of the schedule (activation of power reserves) was achieved. Reconnection to the interconnected grid at 15:08 CET, on the other hand, had no effect on the grid frequency.

Reduction of product recalls and costly image damage through the new product feature ejector monitoring at INDEC 300 systems

Avoid product recalls even before the goods leave production - with the reliable vacuum inspection systems from KoCoS.

With our INDEC range of vacuum inspection systems, food manufacturers have the assurance that HACCP (Hazard Analysis & Critical Control Points) principles are met.
KoCoS vacuum inspection systems are characterised by their superior detection sensitivity and automatic rejection of defective products in the food industry.

The ejector monitoring function checks whether the ejector has separated a container from the product flow that has been detected as bad. For this purpose, another light barrier is arranged parallel to the conveyor belt opposite the ejector. If the light barrier is not interrupted by the bad container within the adjustable delay after the ejector has been triggered, an error message is generated.

Call up the Edit Ejector screen - tap the Monitoring button, set it to ON and enter the manually determined delay. In addition to the error message, an electrical switching signal can be output via a binary output, for example to stop the production process automatically.

The costs incurred by executed recalls, such as publication of warning messages, transport back to the factory and loss of sales, are relatively easy to calculate. But the more far-reaching consequences of the action, such as the loss of brand image among supermarkets and consumers, are not so easy to foresee.

It is precisely under these conditions that smaller manufacturing companies focus on vacuum testing systems from the INDEC series to minimise the risk of product recalls. It is also a way of signalling to the authorities and their trade customers that they meet the required standards and are available for lucrative new markets.

In food manufacturing, a good reputation is particularly important. The less often improperly sealed bottles and jars reach the consumer, the better. Only in this way can manufacturers protect the image of their brand, increase sales and secure their profits.

More and more small and medium-sized enterprises are realising that the best way to achieve these goals is with an INDEC series vacuum inspection system from KoCoS.

When you integrate an INDEC vacuum inspection system into your process, you can be confident that you are meeting current HACCP requirements and that your reputation and customers are reliably protected.

Multifunctional three-phase signal generator

With the EPOS 360 current and voltage source, KoCoS Messtechnik AG offers a signal generator that is recommended wherever maximum performance and the highest signal precision are required.

EPOS 360 has four voltage and three current signal sources. The signal curves are output via electronic power amplifiers. The parameters amplitude, phase angle and frequency can be varied over a wide range during the output.

Intelligent amplifier technology and synthetic signal generation make it possible to output any signal forms over a wide frequency range or even to play complex transient signals.

The TRANSIG monitor, included in the scope of delivery of the EPOS operating software, enables the graphical display and output of recordings that are available in SigDef format or in the standardized COMTRADE format. The corresponding signals are "played back" by EPOS as a transient sequence during tests.

In addition, the EPOS operating software contains a signal editor which enables the parameterization and calculation of any signal characteristics. These can be generated from a basic function, e.g. a sine and its superposition with one or more superposition functions, such as a DC component, exponential functions, harmonics, etc.

For special requirements, such as use in test benches, there is also a simple programming interface. This can be used in COM/ActiveX-supporting as well as in .NET environments.

For more information on EPOS 360, please visit the homepage. Ask our sales department for a quote.

LOTOS LT is a flexibly applicable standard measuring system and extremely cost efficient.
It is suitable for a wide range of applications in the automotive industry, in the field of medical technology, in the plastics and packaging industry, and also for fully automated testing of construction and insulation materials.

It has a height-adjustable operating touch screen and an integrated evaluation unit. Thanks to the small footprint, this standard module is extremely space-saving. The integrated evaluation unit ensures fast and fully automatic measurement evaluations. Inside, the LOTOS LC has various connection options to extend it with peripherals such as code readers. The stand-alone device is suitable for use in a production environment as well as in laboratory or measuring room.

Test parts can be measured at extremely high speed for 2D dimensional tolerances, as well as completely in 3D.

Example of measuring insulation materials:

Video of a measurement run:

Graphical measurement results:


Power Quality Analyzer with universal connectivity


The widespread use of power quality analyzers increases transparency in our power grids and reveals dangers as well as potential savings.

EPPE CX records and analyzes the power quality according to common standards and generates the required reports automatically. Network faults or disturbances are recorded via the transient fault recorder with high resolution.

In parallel to the tasks of power quality and fault recording, EPPE CX can be used via standardized interfaces and protocols, as a data source for third party applications like automation solutions. It also provides real-time visualization of measurement and process data.

Third party systems and automation solutions can access the EPPE CX measurement and process data via the standardized and widely used MODBUS TCP protocol, which is also part of the basic equipment of most PLC systems.

In addition, EPPE CX has been equipped with a modern and powerful webserver interface to display live measurements in numerical and graphical views on all common internet browsers on PCs, smartphones or tablets. Using this feature the live measurements can be monitored from all over the world without the need to install specific software applications.

The widget concept of the browser allows to arrange application specific views easily for each user.


The web server is available from device software version 2.06.0000.

This small video shows how to use the webserver:



For demonstration purposes, an EPPE CX has been permanently installed at the Headquarter of KoCoS in Korbach, Germany, which can be accessed from anywhere in the world.

Click the link to try it out now:


Username: Guest

Password: 2021

Saving of working time through simultaneous resistance determination at three measuring points

For switchgear in the medium-voltage and high-voltage level, the switchgear standard IEC 62271-1 requires a static resistance measurement of the main circuit in order to exclude an unacceptable heating of the current path.

Traditionally, the measurements are carried out one after the other and individually at each phase. The main circuit is supplied with 100 A direct current and the voltage drop is measured. If the measured value, i.e. the voltage drop is within the specified limits, the test is passed and the results can be recorded/stored. This measuring procedure is time-consuming as the three phases are tested one after the other.

To increase productivity and improve reliability, the measuring method for resistance and voltage drop measurement can be optimized with the PROMET R300 or R600.

The PROMET R300/R600 resistance measurement systems are equipped with three voltage measurement inputs, allowing parallel measurement at three measuring points, for example to measure the resistance of three main contacts statically.


In order to perform a simultaneous measurement of three main contacts, the test objects must be connected in series and provided with a test current connection. Since a four-wire measurement is carried out, it is important to ensure that the voltage connections are between the high current connections and that they are connected exactly at the points where the resistance is to be determined.

Connection example for a measurement on three test objects connected in series, e.g. three interrupter units.

In stand-alone mode, the three static resistance results with the measurement details (actual test current and voltage drop, measurement ranges etc.) can be stored in the measurement device.


The data stored in the device can be read out and managed with an easy-to-use PROMET software. The clearly displayed measurement results can also be output in a PDF test report or exported as CSV data.

The described simultaneous measuring method for the acquisition of three resistances thus saves working, changeover and measuring time!

As a further automation option, PROMET R300/R600 are equipped with interfaces for connection to the ACTAS 2.60 switchgear testing software. Resistance measurement can be conveniently integrated via the ACTAS test software. Even without an additional ACTAS test system, automated test sequences and a comprehensive analysis of the test results can be carried out without any problems.


The method is not only applicable in switchgear testing, but also in applications such as e.g. in the field of e-mobility, where several resistors have to be detected at the same time.

If you have further questions, please leave a comment or contact us directly.

Ensuring the highest product quality is a primary and indispensable goal, especially in food production. One of the standardized methods for preserving food without the addition of preservatives is vacuum packaging. By reliably lowering the oxygen partial pressure inside the container, the growth of spoilage germs is suppressed and thus the minimum shelf life of these foodstuffs is significantly extended. However, if the vacuum packaging is not absolutely flawless and has leaks, food can spoil long before the stated expiry date.

Vacuum inspection for bottles, jars and cans

The test procedure is based on determining the vacuum-induced deformation of the container closures as they pass through. The tightness of the containers is assessed by comparison with a previously Golden sample. Depending on the existing basic conditions, vacuum tests are possible from 50 µm deformation or from 150 mbar differential pressure in the headspace to the external pressure.


The INDEC systems work with an optical infrared sensor head. This means that metallic and non-metallic closures can be inspected equally. Starting with flow-rates of up to 600 pieces/min in the basic model, up to 1,200 pieces/min are achieved in the highest expansion stage for cap sizes of 30...110 mm diameter.

Convincing advantages through optical measuring method

The optical measuring method of the INDEC model series has a number of satisfying advantages compared to conventional methods. Due to the large working distance of the sensor head of more than 100 mm, the system is able to fully tolerate a wide range of deviations caused by dimensional deviations of the containers, horizontal track misalignment of the test samples and the unavoi-dable inaccuracies in the manual height adjustment of the sensor head.

Even vibrations of the conveyor belt and occasional drops of water on the caps do not affect the correct operation of the INDEC system, in contrast to other measuring methods.

INDEC the business insurance

Complaints, image damages, loss of customers and high costs are possible consequences of leaking vacuum packaging. The consequences can be serious, especially for the existence of small and medium-sized companies. The use of appropriate vacuum inspection systems should therefore be a matter of course wherever vacuum packaging is produced.

Unfortunately, the consistent use of effective inspection systems in companies that fill food is not a matter of course. During our on-site visits, we repeatedly see production facilities where no such inspection technology is used. The INDEC inspection devices are easy to integrate into existing plants and offer the possibility of updating existing measuring technology to a modern standard at low costs. As a complete installation, the turnkey INDEC test systems offer an "all-round carefree package" with which reliable quality assurance can be achieved quickly and easily.


How it all began

As early as the beginning of the 1990s, KoCoS was able to offer products and solutions in the field of disturbance recording and switchgear testing which were unique in terms of their precision, functionality and simplicity of handling and operation. The basis for numerous innovations was a completely new hardware platform in 32-bit multiprocessor technology. 


DMSS - Digital Measurement Simulation System

For the research, development and product testing of these new device generations, a special signal generator was needed, which was not available due to the special requirements. In order to ensure compliance with the specifications and the quality of the products, a special signal generator, the Digital Measurement Simulation System DMSS, was developed. With this system, it was possible to generate any signal waveforms synthetically by using software and to output them as high-precision analogue values via the appropriate hardware.

At that time, the first digital protection relays were already in use. Their functionality also made great demands on the devices needed for testing. For the most part, conventional test equipment was still in use for relay testing, in which transformers were used to generate the signals. However, these devices were not sufficient for testing digital protection relays.

With the Digital Measurement Simulation System DMSS, KoCoS had developed a signal generator that could also serve as the ideal basis for a new generation of relay test systems. What was still missing were components for measuring analogue and binary quantities as well as current and voltage amplifiers to provide the test values with the necessary amplitude and power.


Ideas, innovations and a new standard

The decision was quickly made to develop a relay testing system. For the measurement part, there were already sufficient solutions available from earlier developments. So "only" powerful and precise current and voltage amplifiers were needed.

But before the development could really get started, a precise specification for the new system had to be created. Of course, we first looked at what the market had to offer specifically for testing digital relays. There was not a lot. In fact, very few, and it was therefore not difficult to find a lot of ideas for the new system. Talks with users in the field of secondary technology, with whom we already had contact from the fault recorder application, were certainly helpful here.

The most important requirement, however, was defined by the management. On the one hand, the new relay testing system should be significantly more powerful and cheaper than the products available on the market. On the other hand, it should have unique selling points and advantages that offer the user a high benefit.

In addition, the new system should also define the future standard for professional testing systems. Not an easy undertaking, but it was completely fulfilled with the introduction of the ARTES 440 25 years ago. The many innovations and special features that the first ARTES 440 already had to offer will be discussed in more detail in future articles about the ARTES USPs.


Is it possible to perform a switching time measurement on a medium voltage system encapsulated in SF6 gas?

KoCoS offers a measuring method using the ACTAS switchgear test systems and external sensors which enables this type of system to be tested at a reasonable cost. As the system does not need to be isolated, the measurement procedure is even less time consuming than testing a non-gas-insulated medium-voltage switchgear using the conventional measurement procedures.

The VDS (Voltage Detection System) installed in the systems is used to measure the switching times. These are capacitive measuring points for voltage indicators or integrated capacitive voltage indicators according to VDE 0682-415 or IEC 61243-5. If no voltage transformers are installed, these measuring points are the only and safe way to establish a connection to the main contacts of the circuit breakers.

The capacitive measuring points can be connected directly to the analog measuring inputs of the ACTAS test system provided for this purpose without interposing additional measuring components. The capacitive measuring points are used to measure the three-phase sine wave of the voltages. If the circuit breaker is switched via the control room, the voltage drop is displayed on the ACTAS test system. However, in order to be able to determine a switching time, current clamps are used and attached to the open and close coils. External trigger signals that can be set in the test system can be used to initiate the recording of the measured values and the corresponding evaluation. External triggers can be set in ACTAS to any signals, regardless of whether they are individual binary or analog signals or signal groups.

The evaluation of the switching time in ACTAS is fully automatic; there is no need to set a cursor to manually evaluate the switching times and enter values manually.

What advantage do FIRST TRIP measurements offer?

As an online test, using the first-trip measurement method with ACTAS has some advantages over offline testing. From an economic point of view, the amount of time that can be saved is particularly relevant, as the disconnection and isolation of the breaker from other equipment is completely eliminated. In addition, there are also savings with regard to maintenance costs and resources if no defects are detected during the online measurement as this may make it unnecessary to carry out a test in offline mode.

  • No need to disconnect the circuit breaker
  • No need to disconnect control circuits
  • Savings in measurement time and resources
  • Breaker sticking/delay can be detected during the first switching operation
  • It may be possible to do without a complex offline test
  • Tests are possible under real conditions
  • No long downtimes for the components to be tested

Using ACTAS, first trip measurements can be performed on three phases. For connection to secondary current transformers, up to nine external analog sensors, such as non-contact DC or AC clamps, can be connected to the test system simultaneously and recorded. Up to three direct voltage measurement channels are available for voltage transformers. The measuring equipment and sensors are mounted while the breaker is in operation. Usually AC/DC current clamps are used which are mounted on the secondary side of the current transformers and on the operating coils. The operating times can be evaluated via the signals recorded accordingly and the characteristic of the coil current can give an indication of the status of the components of the switchgear.

Is it possible to perform FIRST TRIP measurements with ACTAS Px60?

As a component part of the power supply system, a circuit breaker functions primarily as a pure conductor within the network and the only requirement it initially has to fulfil is that its transfer resistance be as low as possible. And this situation often persists for years at a time. As long as no fault occurs, there is no need for the circuit breaker to operate. This is very much in the interests of the network operator, but it poses a considerable challenge to the technology of the breaker because as soon as a fault occurs, the breaker has to interrupt a high fault current within a few milliseconds in accordance with its specifications. This is not always achieved, one of the reasons for this often being inadequate maintenance, and it can be that during the course of the first switching operation the circuit breaker does not open within the time specified by the manufacturer.

One of the causes for this is friction which is created by deposits such as hardened grease or by environmental influences. The problem is usually solved by the first switching operation, as this loosens indurations and deposits. If this is not the case and the problem persists over a number of switching operations, it can lead to serious damage to the breaker itself and to the power network too, of course.

This makes it all the more important to service and test switchgear in accordance with the specified cycles. By measuring the operating times, conclusions can be drawn as to the state of the contact system, and the first trip is, of course, particularly significant. With conventional (offline) measuring methods, however, the breaker is disconnected and earthed before the test and this requires that an initial switching operation be carried out before the measuring equipment is connected.

This makes it impossible to draw conclusions about the behaviour of the breaker during the first trip. This is just one of the reasons why the demand for testing circuitbreakers “online“, i.e. without disconnecting them beforehand, is increasing worldwide. Another reason is that operating and maintenance budgets are constantly shrinking.

In addition, the demands placed on modern testing technology are increasing, using it flexibly and in a way that saves time is a must nowadays. KoCoS Messtechnik AG meets these requirements with its ACTAS Px60 switchgear test systems.

Timing measurements of AIS and GIS switchgear, what are the differences?

GIS high-voltage switchgears are located at many nodes in our voltage network, such as three-phase or single-phase encapsulated switchgear panels. High-voltage switchgears consist of several components and can be designed differently depending on the required function. They contain components such as current transformers, disconnectors, ground switches, circuit breakers, etc. Compared to air insulated switchgear (AIS), they offer a number of advantages, including smaller space requirement, higher personnel safety, a longer service life, and higher reliability. Disadvantages compared to AIS are evident in terms of maintenance, as individual components are very difficult to access. Measurements, such as those of circuit-breaker operating times and resistance of the circuit-breaker interrupter units, are rather difficult to carry out, since the basic requirement is that in high-voltage installations, all the parts being worked on must be grounded.

In outdoor switchgear systems (AIS), measurement with ground on both sides is generally not a major problem, simply because the typical ground resistance is much higher than the main contact resistance. KoCoS uses "Dynamic Timing" to combine the ACTAS switchgear test system with PROMET resistance meters.

The standards DIN VDE0105-100 and EN50110-1 clearly state that a GIS system must be measured with ground on both sides. The problem, which is particularly relevant for GIS, is the very low ground resistance resulting from the encapsulation of the entire switchgear in a metal housing. It often can be that the ground and housing resistance is lower than the main contact resistance. This makes it difficult to carry out a condition assessment of the switchgear using standard measuring equipment.

Use of the Kelvin test probes KP 200 together with PROMET R300/R600

The KP 200 Kelvin test probes were developed for safe and easy resistance measurement at measuring points which are difficult to access. The test probe pair is equipped with spring-loaded high-current and voltage contacts for the determination of low-resistance according to the four-wire method for a test current of up to 200 A.


Can the test probes be used together with the PROMET R300 or R600 resistance meters?

The PROMET R300/R600 are designed with 13 mm high current sockets for the connection of 50 or 70 mm² high current cables. With the reducers 13/9 from 13 mm to 9 mm socket/plug diameter, it is possible to connect high-current cables with a smaller cross-section and 9 mm plugs or sockets to the PROMET R300/R600, such as the CS 205 cable set (2 x 5 m , 25 mm²).
With these cables it is now possible to use the KP 200 Kelvin test probes with the PROMET R300 or R600.


Furthermore, a measuring mode for the safe use of the KP 200 Kelvin test probes has been implemented in the stand-alone operation of the PROMET R300/R600 (from firmware version FWP 1.5).
According to the maximum load of the KP 200 Kelvin test probes, the current output in this mode is limited to 200 A.

If the measurement has started actively, the measuring device waits in this measuring mode for the test probes to be placed on the test object. A measurement is only carried out when the test probes are reliably and completely contacted (voltage and current contact). That is, the test current is output, the best measuring ranges are determined and the resistance value is measured. The measurement is carried out automatically with the shortest possible measurement time.

In order to simplify the use of the test probes on site, the current status of a measurement is also signaled by means of the LED status display and an acoustic signal.
The measurement result now remains on the display until the test probes are removed and the next measurement process is activated by placing the test probes. The resistance measurement results are displayed in a table and the results can be viewed before they can be saved.

With this sophisticated functionality, safe and automated operation of the KP 200 Kelvin test probes together with the PROMET R300/R600 resistance measuring devices is possible.

If you have further questions, please leave a comment or contact us directly.

Share of renewable energy is constantly increasing

In Germany, the share of renewable energies in 2019 was about 43% of gross electricity consumption. In total, about 242.5 billion kWh of electricity were generated from renewable energy sources. 

The aim is to increase the share to 65% by 2030.

The rapid expansion of renewable energy sources in the electricity sector worldwide is definitely the right way forward. However, it also generates undesirable side effects. For example, the structure of the electricity grid, which has grown over decades, is in many parts not designed for decentralized power generation. Many sections of the grid are already operated at the limits of their capacity. The more the decentralized expansion progresses, the more demanding and more difficult it becomes to monitor and ensure Power Quality .

Factors that accelerate the expansion of PQ measurements

The increased demand for PQ measuring points is a direct consequence of the expansion of renewable energy sources and the associated changes to the basic architecture of power supply networks.

There is a continuous and increasing change from a centralized generation model to a decentralized model in order to be able to integrate more and more renewable energy sources - often in smaller power categories and in highly distributed design.

This new model fundamentally changes the characteristics and the electrical signatures flowing in the system.  A change that creates an increasing and urgent need for accurate measurements of power quality at more and more locations within the distribution network. These measurements are not only used to record and monitor quality parameters, but also to detect undesired interactions between network components, which often occur only under certain operating conditions and can lead to shutdowns, unstable operating conditions or a reduction in performance.  

The fundamental changes in our power generation and distribution systems make it necessary to take the monitoring of power quality and the complete recording of all network processes even more seriously in the future.



Our measurement systems of the EPPE and SHERLOG product line offer a reliable and robust platform and can be used on all voltage levels.

Lightweight and compact,

or bigger and heavier than expected?

At first glance, it seems that the ARTES RC3 is the little brother of the ARTES 460 because of the smaller number of inputs and outputs, just extremely robustly packed. It would therefore be expected that the RC3 would also be more compact and lighter than the ARTES 460. According to the specification, however, this is not so.

During the development of the ARTES RC3, high demands were placed on its robustness, reliability and durability. The basis for these requirements was already given with the 4th ARTES hardware generation. This has already proven itself in the ARTES 460/600 and is considered one of the most robust, if not the most robust hardware platform of all relay test systems on the market.

For the integration of the components into the RC3, a specially stable mechanical construction has also been developed inside a hard-shell case. Due to the construction and the robust and resistant hard-shell case, even hard shocks and vibrations have little effect on the RC3.

The dimensions and weight are higher for the first time.  In practice, however, this looks quite different. A relay test system is rarely used in the laboratory or in the workshop. Rather it is transported to the application site. And especially during the transportation the size and the weight are very important. Later during work the test system is moved rather less.

For safe transport, ARTES 460 is equipped with a robust transport box specially designed for this purpose. Inside the box there is a hard foam insert which fits the device and the cable set perfectly and which determines the external dimensions of the box.

Due to its construction in a robust hard-shell case, no additional transport box is required for the ARTES RC3. In comparison, it is a very compact and lightweight system which is very easy to handle in practice. This also makes the ARTES RC3 ideal for demanding outdoor use in rough environmental conditions. Larger and heavier than expected? Rather not.