Huawei is often blamed for stealing information from Nortel that led to Nortel’s bankruptcy, both information about deals being made that let Huawei undercut them and technical product details that allowed Huawei to more easily be a substitute for Nortel products
Nortel collapsed long before Huawei even started competing outside of China in any serious way.
Nortel was severely hit by the bursting of the tech bubble, and then it got caught faking its financial figures. To blame that on Huawei is just a rewrite of history.
If true, how did that have any effect on Nortel? As I said before, Huawei wasn't a serious competitor for Nortel at that point. Nortel's business fell apart (and it started fudging its financials) long before Huawei expanded globally.
No not at all. I is just something that behaves as if it is equivalent to negative one (that is, the additive inverse of the multiplicative identity) after combining it with itself in some way. We commonly call this multiplication. If such a thing comes with another operation called addition that behaves similarly to addition and multiplication (i.e. form a ring), then they will behave like i. Geometrically, multiplication by I can be seen as a 90deg rotation of a 2d vector. Complex numbers are simply 2-d coordinates (or rather, they are isomorphic to 2-d coordinates). Nothing special really. Easy to measure with a protractor and ruler.
In general there are many algebraic rings with an element that, when multiplied by itself, produces the additive inverse of the multiplicative identity.
In math, officially i is the "root" of x^2+1=0 or to be more precise, C is R[x]/x^2+1, i.e. you take all the polynomials in x and pretend that the polynomials A and B they are equivalent when A-B is a multiple of x^2+1.
There is also a construction with matices instead of polynomials.
And perhaps others. Each of them are useful in some cases.
X*X + 1 = 0 is a fundamental statement on an algebraic rings behavior with the additive and multiplicative identities and the additive and multiplicative group operations. Namely, it says that the ring contains an element that when multiplied by itself is equal to the additive inverse of the multiplicative identity . Plenty of rings have such an element. You can complete any ring with such an element and call it whatever you want. The use of the term imaginary for it is incredibly unfortunate. There's nothing strange or mystical about it. It's very real. In fact the rational complex numbers are more real than the non complex real numbers
In general, determining if two arbitrary reals are the same is impossible per the halting problem. People claim to measure 'real' numbers. This is a lie. People can only measure rational numbers. A real number is either a rational or the supremum of some arbitrary set of rationals (perhaps an infinite one). A set is described by whether or not a number is in it. To be able to determine what number is in your set you need to have some sort of decision procedure (a program). However, more real numbers exist than there are possible written programs. Thus, the full set of reals is inexpressible
On the other hand, it's very easy to see and measure rational complex numbers with a protractor.
Dummit and Foote is the classic abstract Algebra textbook to learn about how to precisely define these. Its treatment of ring theory is very well motivated and easy to grasp
Everything makes sense when you see I for what it is -- an escape from the number line rotated by ninety degrees.
Even the roots of a parabola that doesn't hit the z axis are actually the roots of the ninety degree rotated inverse analogue hitting the imaginary plane. Since the apex of such a parabola is always centered at 0i, the imaginary places it hits are symmetric, explaining why if a + bi is one imaginary root, then a - bi is as well.
Again... There is nothing weird about imaginary numbers. They actually make a lot of sense. It's actually insane to only do math in one dimension when our world has three.
I’m still using redmine. It allows me to create a project, break it down in to tasks, assign time estimates for the tasks, assign % complete, log time against tasks, which then allows for burn down charts so I can see if I am on track or behind. With time logged against projects I can generate timesheets and invoices. It also has Gantt chart which is handy for initial project planning meetings.
My wood siding is original cedar that has been painted several times since 1970s when house was built … I haven’t considered it not lasting indefinitely
The condo market is hurting the most. Which is exactly what people have been asking for - lower prices - achieved by vacancy tax, foreign buyer ban, speculator tax, and no rights for landlords.
>Beyond raw performance, the GC Flux PCS features advanced grid-forming capabilities, making it ideal for modern grid applications. It supports active inertia response up to 25 seconds, wide-band damping across 1–1500 Hz, and ultra-fast voltage and frequency regulation in under 100 milliseconds
I wonder what active inertia response is and why it is limited to 25 seconds.
The normal rotating machines have inertia, stored rotational kinetic energy, so when electrical load is added and mechanical power in does not immediately change they new load is fed by the generator very slightly
Slowing down and measured by a decreasing frequency.
How would active inertia be different from the inverter simply putting out more power when frequency drops?
People tend to use the inertia H constant (MW*s/MVA) when it comes to describing the amount of inertia that grid forming inverters and batteries can provide. Sometimes the units are simplified to seconds, which makes it easier to understand how many seconds it could provide rated power for this specific function.
Active inertia or synthetic inertia do vary power when frequency changes but the key is the dynamic behavior. They typically do so by emulating a synchronous machine by implementing something like the swing equation in the active power control (see REGFM_B1 [1]). They essentially emulate the inertia, which makes them have some damping in changing the phase angle and frequency of their voltage waveform just like a spinning synchronous generator would when resisting frequency changes due to physical inertia, resulting in an inertial active power response. This makes it easier for people to analyze because they understand the swing equation from synchronous generators.
A machine with infinite inertia would resist any frequency change and instantly go to maximum or minimum power upon any grid frequency deviation.
A 25s inertia constant is impressive. The hydro units I work on are anywhere from 1s for newer units to 7s for older ones intended to run isolated networks. And then the ease of frequency regulation on the unit is dictated by the inertia of the water in the water conveyance system “water starting time”
So 25s inertia constant would appear to be a response to frequency change much faster and greater than the typical 5% droop implemented by the governors controlling mechanical power applied to the shaft.
Outputting more power when frequency drops is exactly what their active inertia system does, its a feature of the inverter/ battery EMS system. I think there was a communication issue between engineering and the marketing/PR team, as there often is in large companies.
