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Others were
reported, including one in Ishikari City, Hokkaido, Japan.
Validus以380V的电压分配电力，并声称直流配电可以产生巨大的节省。Validus表示，使用直流电的2.5MW数据中心将节省高达25%的能源，按照2009年的价格每年节省300万美元。
Validus
distributed power at 380V, and claimed that DC distribution could produce huge
savings. Validus said 2.5MW data center using DC would use up to 25 percent
less energy, saving $3 million a year at 2009 prices.
在电气配电系统中会有巨大的节省，设备减少50%，安装减少30%，并且只需要一半的物理空间。有了这些简化，该公司承诺它也将更加可靠。
There would be
big savings in the electrical distribution system, with equipment down by 50
percent, installation by 30 percent, and it would only need half the physical
space. With those simplifications, it would also be more reliable, the company
promised.
其他好处包括不再需要同步电力系统。由于电压没有周期性变化，就没有谐波，设备也不会出现同步问题。
Other benefits
include no longer having to synchronize power systems. With no cyclic variation
in voltage, there are no harmonics, and no problem with devices getting out of synch.
“你可以在那个母线上放置任何你想要的直流设备，”Kraus说。“你可以使用燃料电池，你可以使用直流UPS，你可以使用整流器，你可以使用电池，你可以使用风力发电机。所有这些都非常简单。”
“You could
literally put anything you want that’s DC on that bus,” says Kraus. “You could
do fuel cells, you could do DC UPS, you could do rectifiers, you could do
batteries, you could do windmills. And all this stuff is very, very simple.”
尽管有所有这些好处，ABB在2011年表示它收购了一项“突破性”技术，但行业并不信服。
With all these
benefits, ABB said it had bought a "breakthrough" technology in 2011,
but the industry was not convinced.
在反对者中，有影响力的Facebook工程师James Hamilton对所提出的说法表示怀疑：“我详细阅读的营销材料将出色的HVDC设计与非常差的交流电设计进行比较。可预测的节省大约是30%。不幸的是，好的交流电设计与差的交流电设计之间的差异也在30%左右。”
Among the
naysayers, the influential Facebook engineer James Hamilton cast doubt on the
claims made: “The marketing material I’ve gone through in detail compare[s]
excellent HVDC designs with very poor AC designs. Predictably the savings are
around 30 percent. Unfortunately, the difference between good AC and bad AC
designs is also around 30 percent.”
Hamilton估计效率改进可能高达5%，但直流系统的规模小将使设备更昂贵，同时“设备可用性降低，交货时间更长，并且在某些地区获得许可和审批的管辖问题也更复杂，耗时更长。”
Hamilton
reckoned the efficiency improvements might be as much as five percent, but the
small market for DC systems would make the equipment more expensive equipment,
along with “less equipment availability and longer delivery times, and somewhat
more complex jurisdictional issues with permitting and other approvals taking
longer in some regions.”
另一个问题是安全。
Another issue
was safety.
“直流电力分配的一个主要缺点是实现安全的成本更高，”美国超导公司（AMSC）的Ed Wylie说。
“A big drawback
with DC power distribution is that safety is much more expensive to achieve,”
says Ed Wylie, of American Superconductor (AMSC).
他认为这是一个普遍的电气原理。交流电开关可以更小，因为它们的电流会振荡并定期通过零点，在这点上，很容易物理移动开关触点。
He sees this as
a general electrical principle. AC switches can be less bulky, because their
current oscillates and regularly passes through zero, at which point it is easy
to physically move the switch contact.
“对于直流电，”Wylie说，“电流可能会持续，你很快就会烧毁开关。如果你看看直流开关和交流开关的等效额定值，一个是非常庞大，另一个是小巧紧凑。”
“With DC,” says
Wylie, “the current might be maintained, and you burn out the switch fairly
quickly. If you look at the equivalent rating of a DC switch, and an AC switch,
one is monstrous, and the other is small and compact.”
2018年，OmniOn的Vito Savino受雇于ABB并看到了Validus的试验数据中心。他告诉DCD：“我去了纽约雪城大学的一个小数据中心，那是Validus做的试点。”
In 2018,
OmniOn’s Vito Savino was employed by ABB and saw Validus’ trial data center. “I
went to a small data center in Syracuse University, New York, that was kind of
the pilot that Validus had done,” he told DCD. “And it was appropriate
for it to be in a lab environment.”
像Wylie一样，Savino说直流配电因缺乏安全设备而被推迟。“当你在高于SELV（安全超低电压）72V的高电压下运行直流电时，如果有人不小心触摸到错误的地方，他们可能会真的受伤。”
Like Wylie,
Savino says DC distribution was held back by the lack of safety devices. “When
you're running DC at a high voltage, over the SELV [Safety Extra Low Voltage]
level of 72V, you can really hurt somebody if they happen to touch the wrong
places.”
当时，他说：“应该启动的保护装置并不可用。它们还没有为直流电制造，因此它是一种实验，而且进行得并不顺利。它没有得到很好的接受，因为没有人想靠近那种电压。当我们谈论直流电压时，48V是一个安全电压，除非它背后有大量的电流。”
At that time, he
says: “The protection devices that are supposed to kick in were not available.
They weren't made yet for DC, and therefore it was an experiment, and it did
not go very well. It was not well received because nobody wanted to be around
that voltage. When we talk about DC voltages, 48V is a safe voltage, unless
there’s a lot of current behind it.”
正如Savino所说：“从安全的角度来看，我们希望48V被限制在机架内部，只有技术人员才能看到它，他们最接近它的是将断路器插入封装在机柜中的电源分配单元。”
As Savino puts
it: “When we think about it from a safety perspective, we want that 48V to be
contained inside of the rack where only a technician would ever be able to see
it and the closest they get to it is putting a breaker into the power
distribution unit that is encapsulated in the cabinet.”
“有很多人类抵抗，”他说，澄清他所说的是社会对采用这种技术的抗拒，而不是触电，并说这是有道理的。
“There's a lot
of human resistance,” he says, clarifying that he is talking about social
reluctance to adopt the technology, rather than electrocution, and saying that
such is justified.
Validus DC
