PLAN Catapult Development Thread, News, etc.

[nlalyst]

No, it can not be DC vs. AC, China never went the AC path.

Hmm. They don't seem to be quite there yet technology wise. They are still using Western designed and built IEPS systems for their CMSA ships. This one was commisioned last year, and can run on batteries which might imply that it is a MVDC architecture:

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EDIT:
This screenshot from the ABB PEMS system confirms that the architecture is MVDC:

 

[taxiya]

Hmm. They don't seem to be quite there yet technology wise. They are still using Western designed and built IEPS systems for their CMSA ships. This one was commisioned last year, and can run on batteries which might imply that it is a MVDC architecture:

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EDIT:
This screenshot from the ABB PEMS system confirms that the architecture is MVDC:
View attachment 68718

what tech you are talking about? This thread is about the catapult, not IEPS. MVDC or MDAC are core technologies of IEPS, the power grid's main bus. They have nothing to do with catapult. Besides, China is the only country that made the claim to be the first in MVDC application. I have never heard any western country making that claim.

Regarding ABB's work for China's ship, here is what that link said.

The first Chinese-built hybrid emergency rescue vessel is powered by ABB’s bridge-to-propeller technologies, including Azipod electric propulsion, energy storage system and state-of-the-art automation and control solutions.

ABB's contribution is the control system, energy storage system and the drive pod (electrical propeller). Non of them indicates how the power grid (IEPS) is built or by whom. China buys mature products from other vendors like ABB, just like Germany importing Korean cars does not mean Korean cars are more prestigious than Mercedes. (no offence intended to Korea).

 

[taxiya]

Hmm. They don't seem to be quite there yet technology wise. They are still using Western designed and built IEPS systems for their CMSA ships. This one was commisioned last year, and can run on batteries which might imply that it is a MVDC architecture:

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EDIT:
This screenshot from the ABB PEMS system confirms that the architecture is MVDC:
View attachment 68718

The ABB system is low voltage DC as the voltage is only 1KV. MVDC is from 3KV to 10KV.

 

[nlalyst]

The ABB system is low voltage DC as the voltage is only 1KV. MVDC is from 3KV to 10KV.

No. MVDC is from 1kV to 35kV, as specified by IEEE standards:

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Besides, China is the only country that made the claim to be the first in MVDC application. I have never heard any western country making that claim.

That's rich, because the USN has commissioned their first hyrbid MVAC-MVDC ship (DDG-1000) 4.5 years ago. ABB delivered their first Onboard MVDC grid in 2013. Siemens has close to a dozen ships using their MVDC solution. ABB continues to design and develop complete MVDC solutions with international partners, like this Korean fully electric battery powered ferry:

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ABB’s Onboard DC Grid™ power distribution system will ensure that the battery output is delivered to the vessel’s subsystems in the most optimal way, while ABB's Power and Energy Management System (PEMS™) will control the overall power distribution, increase fault tolerance and provide a high degree of reliability.

 

[taxiya]

No. MVDC is from 1kV to 35kV, as specified by IEEE standards:

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That's rich, because the USN has commissioned their first hyrbid MVAC-MVDC ship (DDG-1000) 4.5 years ago. ABB delivered their first Onboard MVDC grid in 2013. Siemens has close to a dozen ships using their MVDC solution. ABB continues to design and develop complete MVDC solutions with international partners, like this Korean fully electric battery powered ferry:

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Important things have to be repeated three times.

IEEE is a standard organization which recommend but does NOT dictate. It is up to individual country and industry sector or company to take their recommendation or NOT. There are many many many other industrial standard organizations than IEEE.

In the case of IEPS in military ship, China regards MDVC as from 3KV and above, below that it is not. You can try to find the US navy's definition of their MDVC IEPS, 1KV is not USN's definition either. Don't pick what you wish as the standard, it's only yours. When we talk about MDVC in this forum we are using what Major General Ma's classified (>3KV) in his research paper. Don't change that standard to fit your purpose.

To entertain you, if you insist 1KV is MDVC, then I am talking about HMDVC (>3KV), your ABB example is still not up to China's standard. Do you see how meaningless you argument of playing standard is?

Your are really something. DDG-1000 is NOT NOT and NOT MVDC at all. This subject has been brought up before. The power bus in DDG-1000 is AC, AC and AC. Their DC part is essentially the end consuming devices, not carrying the main current through the ship. Do you want to see the diagram of DDG-1000's IEPS system by the USN?

The last quote of yours of ABB system is "ABB’s Onboard DC Grid™ power distribution system". Where is MV in ABB's statement? You are very very very rich.

Last question, are you majored in Electrical Engineering? Or any engineering at all? Do you know the meaning of international standard bodies?

 

[nlalyst]

Important things have to be repeated three times.

IEEE is a standard organization which recommend but does NOT dictate. It is up to individual country and industry sector or company to take their recommendation or NOT. There are many many many other industrial standard organizations than IEEE.

In the case of IEPS in military ship, China regards MDVC as from 3KV and above, below that it is not. You can try to find the US navy's definition of their MDVC IEPS, 1KV is not USN's definition either. Don't pick what you wish as the standard, it's only yours. When we talk about MDVC in this forum we are using what Major General Ma's classified (>3KV) in his research paper. Don't change that standard to fit your purpose.

All the research papers written in English on this topic that I looked up referred to the IEEE definition. Some research papers by authors who advised the design of the USN's IFEP system for the Zumwalt class and the future LSC referenced both the IEEE definition and the Navy's legacy definition whereby anything of 1000 volts or higher is considered high voltage. Therefore, I haven't changed or invented anything to fit my purpose. MVDC (IEEE definition) onboard grids for vessels with propulsion powers up to 20MWs are already an established technology with 8 years of in-service history for companies like ABB and Siemens.

AFAIK, China hasn't deployed yet a MVDC IFEP ship according to Gen. Ma's definition? I've seen an IEEE paper on a prototype 3kV MVDC generation system built for the Italian Navy published in 2010. However, I am still waiting to see a ship with that class of MVDC IFEP to be commissioned.

Your are really something. DDG-1000 is NOT NOT and NOT MVDC at all. This subject has been brought up before. The power bus in DDG-1000 is AC, AC and AC. Their DC part is essentially the end consuming devices, not carrying the main current through the ship. Do you want to see the diagram of DDG-1000's IEPS system by the USN?

No. The diagram of DDG-1000s IFEP architecture is of course classified. One of the people who worked on the project published the following schematic that he claimed roughly resembles what is implemented on the DDG-1000. The PDM-A (powed distribution module) is the HVAC bus (4.16kV-13.8kV 60Hz). PMM=Propulsion Motor Module. PGM=Power Generation Module. According to him, PDM-A is confined to the main engineering space and directly powers only the PMMs which are the AIMs on the Zumwalt. PDM-B are dual 1000 VDC buses that run most of the length of the ship and power all other systems. Also visible on the schematic are auxiliary power generation connected to the two DC buses. There could also be Energy Storage Modules hooked to the DC buses.

 

[silentlurker]

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"The drivetrain propelling the ship features four motors, two in tandem for each propeller (with electric power delivered by four, Rolls-Royce diesel turbine generators). GE VDM25000 power converters with three independent channels accompany each 15-phase AIM"

VDM25000 are used on the 11KVAC systems on the QE class aircraft carriers.

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[taxiya]

All the research papers written in English on this topic that I looked up referred to the IEEE definition. Some research papers by authors who advised the design of the USN's IFEP system for the Zumwalt class and the future LSC referenced both the IEEE definition and the Navy's legacy definition whereby anything of 1000 volts or higher is considered high voltage. Therefore, I haven't changed or invented anything to fit my purpose. MVDC (IEEE definition) onboard grids for vessels with propulsion powers up to 20MWs are already an established technology with 8 years of in-service history for companies like ABB and Siemens.

AFAIK, China hasn't deployed yet a MVDC IFEP ship according to Gen. Ma's definition? I've seen an IEEE paper on a prototype 3kV MVDC generation system built for the Italian Navy published in 2010. However, I am still waiting to see a ship with that class of MVDC IFEP to be commissioned.



No. The diagram of DDG-1000s IFEP architecture is of course classified. One of the people who worked on the project published the following schematic that he claimed roughly resembles what is implemented on the DDG-1000. The PDM-A (powed distribution module) is the HVAC bus (4.16kV-13.8kV 60Hz). PMM=Propulsion Motor Module. PGM=Power Generation Module. According to him, PDM-A is confined to the main engineering space and directly powers only the PMMs which are the AIMs on the Zumwalt. PDM-B are dual 1000 VDC buses that run most of the length of the ship and power all other systems. Also visible on the schematic are auxiliary power generation connected to the two DC buses. There could also be Energy Storage Modules hooked to the DC buses.
View attachment 68719

So you really enjoy being face slapped by hard evidence?

Here is a presentation by ONR of US Navy. I have highlighted what you need to read.


MIL-STD-1399 standard by US navy

FORMAT OF DRAFT STANDARDS
Two different draft standards were created. The first defines three standard voltages for medium voltage d.c. power generation and distribution: 6 kV, 12 kV and 18 kV. The voltage levels are based on recommendations from IEEE Std. 1709, a desire to keep generator and main distribution currents below 4000 amps (to avoid thermal issues with switchgear and reduce the weight of distribution cabling), and the availability of power electronics. This standard was given the “working” name MIL-STD-1399-MVDC. The actual designation for this standard will be different when it is eventually approved.
The second standard, given the working name MIL-STD-1399-LVDC, defines standard voltages of 375 volts, 650 volts and 1000 volts. These voltage levels are common with equipment on DDG 1000 and similar to voltages used in a number of systems in development. The 375 volt level is consistent with an industry telecommunications standard (ETSI 2011). Several mission system programs were consulted and validated that their designs could accommodate the three standard voltages while still meeting the objective to reduce power conversion equipment within the mission systems.

Do you see how USN has defined their MVDC? Or you want to beat USN with IEEE?

Another paper by Naval Sea Systems Command, U. S. Navy
NEXT GENERATION INTEGRATED POWER SYSTEMS FOR THE FUTURE FLEET
Capt. Norbert H.

Do you seriously think that the US naval command does not know their ship better than you? Stop using "classified" to cover your back-end, these information is open, google yourself.

Please, save yourself and don't waste our time. You are already derailing the thread "Catapult" by IEPS and definition of medium voltage. If you enjoy, go and open a separate thread "what is MVDC", I am sure the stage is all yours.

 

[nlalyst]

So you really enjoy being face slapped by hard evidence?
...
Please, save yourself and don't waste our time. You are already derailing the thread "Catapult" by IEPS and definition of medium voltage. If you enjoy, go and open a separate thread "what is MVDC", I am sure the stage is all yours.

Sorry, but I don't see why you find it justified to berate and patronize me over this issue, especially when I looked back a few pages prior to my post and found plenty of discussion on MVDC and MVAC (by yourself) that was never flagged by moderators. If I am wrong, fine. Point it out and I will learn and change my viewpoint. But not in this barbaric manner.

One of the Naval Systems Command quotes you posted were written by Dr. Norbert Doerry. I looked up his references on the new standard, and this is what he had to say in a a paper from 2016 (Design Considerations for a Reference MVDC Power System):

MVDC is defined by IEEE Std 1709-2010 as dc voltages above 1kV and up to and including 35 kV. The U.S. Navy considers all voltages 1 kV or higher as high voltage.

Therefore, according to US Navy, 1000 VDC grid on the Zumwalt is high voltage, but low voltage according to Dr. Doerry and the new naval voltage inferface standard he is proposing. Furthermore, 1000 VDC would not appear to qualify as MVDC by IEEE per above statement. It has to be 1001 VDC or above. Therefore, the ABB onboard DC Grid with a nominal 1000 VDC would not qualify for MVDC either, the 1042 VDC visible in the screenshot of ABB PEMS I posted above notwithstanding. I concede my mistake.

 

[taxiya]

Sorry, but I don't see why you find it justified to berate and patronize me over this issue, especially when I looked back a few pages prior to my post and found plenty of discussion on MVDC and MVAC (by yourself) that was never flagged by moderators. If I am wrong, fine. Point it out and I will learn and change my viewpoint. But not in this barbaric manner.

One of the Naval Systems Command quotes you posted were written by Dr. Norbert Doerry. I looked up his references on the new standard, and this is what he had to say in a a paper from 2016 (Design Considerations for a Reference MVDC Power System):

Therefore, according to US Navy, 1000 VDC grid on the Zumwalt is high voltage, but low voltage according to Dr. Doerry and the new naval voltage inferface standard he is proposing. Furthermore, 1000 VDC would not appear to qualify as MVDC by IEEE per above statement. It has to be 1001 VDC or above. Therefore, the ABB onboard DC Grid with a nominal 1000 VDC would not qualify for MVDC either, the 1042 VDC visible in the screenshot of ABB PEMS I posted above notwithstanding. I concede my mistake.

Because you are doing the following:
1. inserting an off topic subject (IEPS and MVDC) into the discussion of Catapult
2. insisting to continue off topic after being reminded.
3. Making irrelevant claim (IEEE) of the inserted subjects (Naval IEPS).
4. Repeating the irrelevant claim even after being reminded to research what the relevant entities (Naval IEPS) defines.
5. Insisting to twist the standard (Naval practice by China and US) to fit your argument.
6. In the last highlight, you once again repeated a claim not backed up by an official document, while disregarding statements in two official documents.

Nobody could be so patient to talk to a pretending deaf (that is you), if you do it once or twice I can accept you are making honest mistakes, but third and forth time, I take that you are being deliberate and trolling, what else do you expect?