KoCoS Blog

For many years, KoCoS has been recognized as the world's leading manufacturer of switchgear test systems. With the new ACTAS P260+ and ACTAS P360+ switchgear test systems, KoCoS now offers two portable devices which once again overtop the previous series in terms of performance.

  1. Larger range of functions thanks to new hardware and software features
  2. Increased flexibility in switchgear testing
  3. Improved ergonomics, functionality and performance
  4. Operation via integrated operating unit with 7" touch screen and/or the specially developed test software
  5. Easy operation with optimal display of all information
  6. Built in an extremely robust and compact case housing

ACTAS P360+ has been extended by two controllable outputs in the form of relays, which can be easily integrated into the test sequence. This also works retroactively with existing test templates from the pre-production series. ACTAS P260+ also received two additional control outputs, one also in the form of a relay, the other as an IGBT control output. For example, the reserve output coil of a switchgear can be connected directly without reconnection, which enables the connection of one input and two output coils simultaneously. The systems offer another major advantage with the display of measurement data oversampled at 200 kHz at 50 kHz.

There is also news in the testing software. ACTAS EXPERT is now generally included in the scope of delivery and offers some additional functions. Among other things, it is possible to export measurement data in various formats, to overlay measurement data using the measurement history and compare them directly, or to insert envelopes as a reference. For the display and analysis of the data, you can also create your own display graphics, which are also used in the corresponding test reports.

Do you have any questions, additions to the topic or would you like to convince yourself of the performance of the systems during a product demonstration online or in person at your premises? Then feel free to contact us via the comment function here in the blog or by e-mail to cstuden(at)kocos.com.

Gas has been getting more and more expensive for a year now, and the price of electricity in Europe is also rising significantly. Are these prices related and what role does which power plant play in this?

Gas shortage. Why is the price of electricity rising at all?
Since in Germany, as in the rest of the world, electricity is mainly generated by fossil fuels, the price of a kilowatt-hour naturally depends on the basic price of gas, coal, oil and, to a certain extent, uranium. If the prices of fossil energy sources rise, the price of electricity also rises.

How have energy prices developed so far?
Concerns about a shortage of gas supplies from Russia have driven gas prices ever higher, and not only in Germany. Power plants paid almost 227.0 percent more for natural gas in June 2022 than in the previous year. The gas bills of many end consumers have tripled. Alongside these rapid increases in prices in the gas market, electricity prices have also risen at the same time. Within one year, for example, the price of electricity on the Leipzig European Power Exchange (EEX) has increased 10-fold (as of August 2022) - from 50 to 565 euros per MWh. Of course, this also has a knock-on effect on consumers: the electricity price for new contracts in mid-November 2022, for a consumption of 4,000 kWh incl. basic fee, was 0.427 euros per kWh - and the trend is uncertain.

And what about electricity from renewable energies?
Electricity from renewable energies is by far the cheapest way to generate electricity. Once wind or solar power plants are built, they consume almost no resources for direct electricity production. However, they do not supply electricity continuously. This means that although energy from these sources is cheap, it is not constantly available everywhere without large storage facilities and well-developed electricity grids. Does the price of electricity fall when more electricity is fed into the grid from renewable sources? No, unfortunately it is not that simple. This is because the electricity market works according to the "merit order" principle.

Definition: Merit order
The merit order is the order in which power plants are deployed, which is determined by the variable electricity production costs. The cheapest power plants are switched on first to meet demand, and the last power plant with the highest marginal costs needed to meet demand determines the price. The merit order thus determines the electricity price on the energy markets.

In a simplified way, this means: All power plants offer their production capacities until enough electricity is produced in Europe to cover demand. However, no distinction is made in the type of generation: All suppliers receive the same price, determined by the most expensive power plant on the grid. In the merit order principle, for example, it does not matter at all how cheaply the renewable electricity was generated. Subsidies for the expansion of renewable energies do not count either.
Thus, at present, a single gas-fired power plant on the grid is enough to greatly increase the price of a kilowatt hour of electricity, regardless of the low costs of other energy sources or "power plants" at that time.

So why is there a "merit order"?
In a conventional market, supply and demand would determine the price - until the time when a product is no longer available. As a result, however, gas-fired power plants would then almost never be in operation, as cost-covering operation is not guaranteed. The "merit order" balances this out so that there is always enough electricity available to meet demand and the grids remain stable.
Each producer offers its electricity in such a way that its costs (marginal costs) are covered. All offers are then successively made until demand is covered - the most expensive power plant used then determines the price for everyone. This power plant only covers its marginal costs, all others make profits. The resulting price is called the marginal price.
Marginal costs are the costs incurred to produce the next commodity or, in this case, the next megawatt hour. Investment or capital costs are not included, but fuel costs, for example, are.
On the energy market, it generally applies that the "product" electricity must not be "sold out", as otherwise the energy supply can be disrupted and, in the worst case, a local or area-wide blackout could occur.

Who invented the merit order principle?
"The marginal price (found through the merit order) is not an artificial rule that someone made up," Lion Hirth elaborates in the Stuttgarter Zeitung. Lion Hirth is junior professor for energy policy at the private Hertie School in Berlin and managing director of the energy consulting company Neon. "It is not an arbitrary choice between alternative market designs, but the natural way prices form in free markets," he continues. Other commodity markets also function according to this principle - "no matter whether it is oil, gas, copper, milk or solar plants", says the energy expert.

What is happening at the moment?
Currently, several developments are coming together: Firstly, about half of the 56 nuclear power plants in France are currently out of operation due to maintenance work or technical defects. Secondly, the low water level of the rivers is hampering the supply of coal to the coal-fired power plants. And thirdly, the gas price is at a high level and, as described above, influences the electricity production costs.

Will coal, nuclear power and renewable energies not suffice?
Unfortunately not. On the one hand, this is because the current capacities of hydropower, wind power and photovoltaics are not sufficient to cover the entire electricity demand, neither in Germany nor in Europe as a whole. In addition, as described above, many conventional power plants are currently shut down or can only be operated to a limited extent.
Furthermore, there is a lack of transmission grid capacities across Europe. Often, for example, the electricity generated on the windy North Sea coast in Germany cannot be transported to the energy-hungry south of Germany. The Federal Network Agency reacts to such a bottleneck with a "Redispatch": the output of wind turbines is reduced in the north and the output demand of the power plants is increased in the south so that an overload of the electricity grid is avoided. Gas-fired power plants, which can adapt their electricity production particularly flexibly and quickly, are often used here. Of course, this also has additional effects on the electricity price.

Opportunities for action and risks
The increased gas price, mainly caused by the war in Ukraine, is also driving up electricity prices. Since electricity is included in the prices of many other products, including breakfast rolls, this is fuelling inflation. For weeks, there have been many discussions on how the price increase could be stopped.
"A discussion about redistributing profits and relieving the burden on consumers, but maintaining savings incentives, i.e. not a simple price cap, is in my opinion the way to go in the short term," says Christoph Maurer, Managing Director of the Aachen-based energy consulting firm Consentec. However, a fundamental change in the market design should definitely not be decided in the short term, he warns. "The risk of then arriving at solutions that have not been thought through and possibly even intensifying the crisis is very high" Maurer, an energy expert, told the Stuttgarter Zeitung.

References: The magazines: "Zeit, Standard and Stuttgarter Zeitung", the technical magazine "Chip", Wikipedia and own research.

Six-Sigma in silicon carbide substrate manufacturing with LOTOS 3D
measurement systems.

Achieving the stringent zero defect strategy in the automotive industry is becoming a major challenge for silicon carbide substrate manufacturers. Both the switch from 150 to 200 mm wafers and the general shift in their focus away from pure silicon are making manufacturers struggling to achieve sufficient yields and reliability.

SiC is a combination of silicon and harder carbide materials, and its wide bandgap has made it a key technology for battery-powered electric vehicles. Silicon carbide operates at higher power, higher temperatures and higher switching frequencies than silicon. These properties can be used to increase the range of electric vehicle batteries and reduce charging time.
"People want to charge their cars in less than 10 to 15 minutes, and that's going to continue to evolve," said Sam Geha, CEO of Infineon Technologies' Memory Solutions. "That requires silicon carbide and other technologies, as well as more automation."

LOTOS 3D measurement systems help implementing the zero-defect strategy toward high-yield production processes without any scrap. Shortly after crystal growing, silicon carbide boules can be inspected for geometric sizes, eliminating scrap in subsequent production processes.

LOTOS checks all common parameters such as outer diameter and diameter at the primary and secondary flat, the flat lengths, the notch contour, as well as their exact angular positions.

Power Quality

The European standard EN 50160 describes the main characteristics of the supply voltage at the customer's point of connection in public power supply networks. It specifies the limits that must be respected by the various parameters of the mains voltage under normal operating conditions.
Essentially, the following parameters must be permanently monitored:

  1. Voltage amplitude
  2. Frequency
  3. Symmetry
  4. Flicker
  5. Harmonics

For example, EN50160 allows a tolerance of +-10% of the nominal voltage for voltage deviations, which must be met by 99% of all measured values within a weekly interval. For the remaining 1% within a week, a deviation of +10 and -15% is allowed.
10-minute average values are used to determine the voltage deviation. The specified deviations therefore apply to slow voltage changes.
For the other parameters such as frequency, total harmonic content, individual harmonics, ripple, flicker, etc., the same procedure is followed. However, with different limit values, percentiles, averaging and sometimes other observation intervals.

Power System Disturbances
As a result of mains disturbances, rapid voltage changes usually occur, the measured values of which are determined 2 times per mains period (rms1/2). If the measured value falls within a range of 1% to less than 90% of the nominal voltage, this is called voltage dip. If the measured value of all phases falls below the 1% threshold, there is a supply interruption. Measured values greater than 110% of the nominal voltage are referred to as an overvoltage.
Power disturbances are classified according to their duration and the amplitude reached.

Power Quality Report
Since these power quality thresholds are valid only for the undisturbed operating case, measured values accumulated during a power disturbance must be marked and excluded from the statistical power quality assessment.
The Expert operating software for the EPPE and SHERLOG devices can perform this work automatically on request. It generates fully automated, standard-compliant power quality reports from all measuring points over definable observation periods.
The content of the reports can be customized and, in addition to the standard-compliant power quality verification, also includes information on the number and duration of supply interruptions, voltage dips and swells, including classification according to UNIPEDE, CBEMA, ITIC and SEMI F47.
Also signal fluctuations and statistics on current, active, image and apparent powers, as well as power factor can be included in the report.
The reports can be automatically saved as PDF or DOCX files for later use and sent to network printers and e-mail addresses.

Brian Burke, Application Engineer, KoCoS America LLC
Guy Wasfy, Managing Director, KoCoS America LLC
Jürgen Dreier, Product Manager, KoCoS Messtechnik AG

Bonding connections and ground connections are an essential component for the safe functioning of power and communications engineering systems and for ensuring personal and equipment safety.
Unwanted voltage potential differences are to be avoided by means of ground connections and grounding procedures. These voltage potential differences can occur between metallic components and ground, which can endanger human safety and/or technical equipment.
Metallic components must be connected to ground potential to prevent dangerous voltages. Voltage drops are reduced by grounding all non-voltage-carrying parts and by extensive ground potential equalization (grounding system). It is important to make sure these grounding connections have a low resistance. Resistance measurements must be made at both potential and ground connections to ensure that a sufficiently good low resistance connection is achieved and maintained.

Below is an example of application in power distribution where grounding and equipotential bonding and their good connection are important.  However, there are many other applications where grounding and equipotential bonding must be taken into account (Rail vehicles, aviation industry and aircraft maintenance, etc.). Typical applications for equipotential bonding and grounding are found in power distribution substations in low and medium voltage networks and especially in high voltage substations. The grounding of all non-voltage-carrying parts and extensive ground potential equalization reduce voltage drops that can occur due to capacitive or even inductive voltage coupling.

An example of these non-voltage-carrying parts is the mechanical disconnect switches used to remove a switchgear from service. Due to the need for human interaction with these physical switches, it is critical their grounding connection is not compromised. These straps are metallic braids secured via bolts to the switch and ground connection point. These straps can become poor conductors due to corrosion or physical damage. A compromised strap could lead to improper grounding of the switch causing a hazardous touch potential when the switch is to be used. To ensure the straps are functioning accordingly, the connection across them can be tested with a micro-ohm measurement. A failing strap will have a high resistance reading where as a properly conducting strap will have a low resistance reading. High resistance of the connection or, in the worst case, a failing strap could require the bolted connection points being cleaned and reconnected or the strap being replaced entirely.

Aside from bolted ground straps, the grounding connections can be bonded through exothermic welds. These welds result in superior mechanical and electrical bonding. Especially for conjoining dissimilar metals, such as joining a copper grounding rod to a galvanized metallic structure in a substation. These welds, when done properly, create a solid and reliable connection (Figure 2) Due to improper heating or unwanted moisture, the welds can have pitting or gaps (Figure 3) and be considered poor quality both mechanically and electrically. Performing a micro-ohm resistance measurement across these connections can give insight into the weld quality. The more solid the weld connection is, the lower the resistance reading will be. A poor quality weld could result in a less reliable grounding connection.

The resistance measuring instruments from KoCoS Messtechnik AG are ideal for measuring equipotential bonding and earth connections. The PROMET SE precision resistance measuring instrument is used to determine low-resistance in the μΩ and mΩ range. With adjustable test currents of up to 200 A, in conjunction with a four-wire measurement method, the systems provide measurement results for the highest accuracy requirements. The use of state-of-the-art power electronics and the robust design guarantee maximum reliability for mobile use.

The PROMET SE is ideal because it is battery operated and does not require a mains connection. Some of the connections described may be at height so that the tester is standing on a ladder or similar. Without the battery operation, the meter would also require a portable generator. Finally, the PROMET SE is very lightweight and easy to transport.  It weighs less than 5 pounds and can be conveniently transported on-site to test the many ground connections.

If you have questions or additions to the resistance measurement or to our measuring devices? Then contact us via the comment function here on the blog or by mail to info(at)kocos.com.