Cable termination: new technologies? 

Cable termination: new technologies? A question that turns out to be more difficult than it seems. Everyone talks about “new”, but in practice you often end up with repackaged old solutions or half-baked innovations that create more problems than they solve. Let's try to figure it out without gloss.

What is hidden behind the fashionable word “new”?

When you see another catalog with a loud title about the revolution incable termination, the first desire is to check the technical data. Often ?novelty? comes down to a change in the color of the polymer or the shape of the case, while the key parameters for tracking resistance, UV resistance or operating temperature range remain the same. I remember a case with one batch of heat-shrinkable terminations, where the manufacturer focused on “innovative”? glue formula. In fact, when installed in conditions of high humidity (+3°C and dampness), adhesion turned out to be catastrophically weak. I had to urgently look for a replacement, but the project stopped.

That is why now I always look not at marketing sheets, but at independent test reports. Particularly important are temperature cycling and partial discharge tests. Without this, any ?new? is a lottery that simply cannot be played at a responsible facility.

By the way, about independence. Sometimes it's useful to look at who is behind a brand. For example, a Chinese companyShijiazhuang Hist Electric Co.,Ltd(website -histe-ru.com) positions itself as a professional manufacturer of accessories, including terminations. In their case, having dozens of patents and expertise in related fields, such as isolating switches, is already a serious claim. But again, patents are different from patents. What matters is whether they protect a real technological advantage or just a design advantage.

Materials: evolution, not revolution

If we put aside the hype, I see real progress in recent years in the materials. We are not talking about something fantastic, but about a gradual improvement in properties. Let's take silicone rubber for filler ends. Previously, there was an eternal problem with outgassing and shrinkage during long-term use, especially on tires under constant load. Now the lineups have become more stable, but there are nuances here too.

One supplier claimed that its material was completely stable. We conducted long-term (albeit makeshift) tests - we placed samples in a heat chamber, simulating heating-cooling cycles. After a couple of hundred cycles, microcracks appeared on some samples. Not critical for a test report, but hints at possible problems after 5-7 years of operation. Therefore, we now reserve material for critical facilities and insist on providing samples for preliminary testing under our conditions.

Or here are polymers for heat shrinking. We have improved resistance to solar radiation, which is a huge plus for open switchgears. But at the same time, some brands have become more capricious. to the installation temperature. Do not heat the builder with a gas burner and you get incomplete shrinkage with air pockets. The technology requires not only new materials, but also a new installation culture.

Compatibility problem: old cable and new solutions

A separate headache that is rarely written about in brochures. Often ?new technologies? The terminations are designed for cables with modern, smooth and clean XLPE insulation. But what to do when you need to redo the connection on an old, say, paper-oil cable from the 70s, the insulation of which is covered with micropores and impregnation residues?

We tried to somehow use a modern heat-shrinkable sleeve with an adhesive layer. Technically, it matched the diameter. But the adhesive, designed for polyethylene, simply did not adhere well to the old surface, despite careful cleaning. As a result, I had to combine it - use the good old brass sleeve with soldering and apply modern insulation on top of it. The hybrid approach worked. Conclusion: sometimes the new must be able to work with the old, otherwise it is not technology, but a toy for ideal conditions.

Installation process: simplification or complication?

Manufacturers like to say that their new products radically simplify installation. ?Installation in 30 minutes!? - you read and want to check. In fact, these 30 minutes begin from the moment when the cable is perfectly stripped, the surface is degreased, the ambient temperature is +20°C, humidity is 50%, and the installer already has ten years of experience working with this particular system.

In reality, at a substation in winter, in wet snow and gusty winds, even with the most “simple” conditions. problems may arise with the system. For example, the same poured design. New two-component formulations that need to be mixed on site. In theory - simple. In practice, if the components were stored in a cold warehouse, their viscosity changes, the pot life of the mixture is reduced, and the installer may make a mistake in a hurry. I saw the consequences - non-polymerized inclusions inside the coupling, which led to a breakdown a year later.

Therefore, for me the criterion of “novelty” technology is not only the final characteristics, but also its resistance to the “human factor?” and non-ideal conditions. A good system should be forgiving of minor errors, and not require elaborate work in a sterile laboratory.

Tool: behind the scenes technology

Rarely does anyone associate new termination technologies with a new tool, but in vain. The transition to more advanced press sleeves with controlled crimping force also required an appropriate hydraulic tool. I remember how they tried to compress such a sleeve with an old mechanical press. The connection seemed to work, but contact resistance tests showed instability. It turned out that without calibrated force and deformation control, the internal structure of the conductor is disrupted. I had to invest in a new tool. So what is ?new technology? often entails a chain of costs that are not specified in the specifications.

Economics of “new”: is the game worth the candle?

Here it all comes down to the object. For a new substation with a design life of 40 years, the use of the most modern, albeit expensive, systemscable terminationmay be justified. Their increased reliability and possibly lower operating costs will pay off.

But there are a lot of situations where the “old tried and true” the solution will be both more reliable and economical. For example, a planned replacement of one termination in an existing cell, where all other connections are made using old technology 15 years ago. To install a super-new product here, requiring different installation conditions and, possibly, a different approach to diagnostics, means creating a “weak link”. already because of its dissimilarity from the rest of the system. Sometimes the reliability of a system lies in its uniformity.

Therefore, our approach is differentiated. We don’t chase all the new products in a row, but we don’t reject them either. First, an analysis of the conditions of a particular object, then a request from manufacturers such as the one mentionedShijiazhuang Hist Electric Co.,Ltd, real feasibility studies. Not “it’s better because it’s new?”, but specific figures for reducing losses, increasing service life, and simplifying repairs. Without this conversation, any implementation is a step into the dark.

Looking to the future: where to go?

If we talk not about marketing, but about real needs, then the main directions of development forcable terminationsseem like this. The first is built-in diagnostics. Not just a coupling, but a coupling with partial discharge or temperature sensors, with the possibility of remote monitoring. For now, such solutions are rare and expensive, but they are the future for critical facilities.

The second is environmental friendliness. Tightening of recycling standards and requirements for materials. This will push for the development of new polymers, perhaps with a different chemical composition. And here again, balance is important - so that environmental friendliness does not come at the expense of reliability.

And third, the most prosaic - further standardization and unification. So that an on-site installer, having received a box with a coupling from any serious manufacturer, be it a European brand or a Chinese manufacturer like Hist Electric, can perform the job efficiently using clear, uniform instructions. Because ultimately, the most advanced technology is useless if it cannot be applied correctly in the field. And this, it seems to me, is something that the industry still has to work on.