工程单位与技术参数
一、基本物理量 | Fundamental Physical Quantities
二、长度与距离 | Length & Distance
三、面积与体积 | Area & Volume
四、质量、力与压力 | Mass, Force & Pressure
五、温度与热量 | Temperature & Heat
六、电气单位 | Electrical Units
七、速度与流量 | Velocity & Flow
八、技术参数与性能指标 | Technical Parameters & Performance
九、单位换算 | Unit Conversion
Design Review Meeting — Units & Technical Parameters
Okay, let's go through the transformer specification sheet. Zhou, can you walk me through the key parameters?
好，我们过一下变压器规格表。周工，你能给我讲讲关键参数吗？
周工: OK。This is a 100 MVA main power transformer, rated voltage 230 kV / 34.5 kV, 3-phase, 60 Hz.
好的。这是一台100兆伏安主变压器，额定电压230千伏/34.5千伏，三相， 60赫兹。
Wait — 100 MVA or 100 MW? There's a difference.
等等——是100兆伏安还是100兆瓦？这有区别。
周工: Right. MVA is apparent power, MW is active power. At 0.9 power factor, this transformer can deliver 90 MW of active power.
对。MVA是视在功率，MW是有功功率。在0.9的功率因数下，这台变压器 能输出90兆瓦的有功功率。
Got it. And the impedance?
明白了。阻抗呢？
周工: Impedance is 12.5%, ±7.5% tolerance. Cooling is ONAN/ONAF — that's Oil Natural Air Natural for the first stage, Oil Natural Air Forced for the second stage when it heats up.
阻抗是12.5%，±7.5%的公差。冷却方式是ONAN/ONAF——第一级为自然油冷 自冷，温度升高后第二级切换为自然油冷风冷。
On the vendor side, I just want to confirm: the temperature rise limit is 65°C above ambient, correct? We need to know this for the cooling design.
从供应商的角度，我想确认一下：温升限值是环境温度以上65°C，对吧？ 我们做冷却设计需要这个数据。
周工: Yes. Ambient temperature is specified as 40°C maximum, so the maximum winding temperature would be 105°C.
对。环境温度规定最高40°C，所以绕组最高温度是105°C。
Let me jump in — I'm seeing mixed units in the spec. Some values are in metric, some in imperial. For example, the foundation dimensions are in feet and inches, but the transformer weight is in metric tons.
我插一句——我看到规格书里单位混用了。有些值是公制的，有些是英制 的。比如基础尺寸用英尺和英寸，但变压器重量用公吨。
周工: Ah, yes. That's because we used the US structural engineer's drawings for the foundation, but the transformer data came from the European manufacturer.
啊，是的。这是因为我们基础用的是美国结构工程师的图纸，但变压器数 据来自欧洲制造商。
That's fine, but we need to make sure there's no conversion error. A single mistake in unit conversion can cause major problems.
那倒没问题，但我们得确保没有换算错误。一个单位换算错误就能出大 问题。
For the record: the transformer weight is 185 metric tons. In US short tons, that's about 204 tons. Make sure the crane capacity is spec'd in the right units.
记一下：变压器重量是185公吨。换成美制短吨，大约是204吨。确保起 重机的起重能力用的是正确的单位。
Good catch. We once had a project where the lifting plan was in metric tons but the crane was rated in short tons. Nobody caught it until the day of the lift. Very dangerous.
提得好。我们之前有个项目，吊装方案用的是公吨，但起重机的额定荷载 是短吨。直到吊装那天才被发现。非常危险。
周工: I'll add a unit conversion table to the specification sheet.
我会在规格表后面添加一个单位换算表。
Perfect. Now, let's talk about the performance parameters. What's the efficiency spec?
很好。现在谈一下性能参数。效率指标是多少？
周工: At rated load, efficiency is 99.5% minimum. At 50% load, it's 99.3%. These are tested per IEEE C57.12.00 standard.
在额定负载下，效率最低99.5%。50%负载时为99.3%。这些按照IEEE C57.12.00标准进行测试。
And the noise level?
噪音等级呢？
周工: Maximum sound level is 75 dB at 1 meter from the transformer. Measured per NEMA TR-1.
最大噪音等级为距离变压器1米处75分贝。按照NEMA TR-1标准测量。
We can meet those specs. Just need final confirmation on the environmental conditions: the site is at 1,200 meters elevation, right? That affects the cooling design because of lower air density.
我们能达到这些指标。只需要最终确认环境条件：现场海拔1200米，对吧？ 这会影响冷却设计，因为空气密度更低。
周工: Correct. Site elevation is 1,200 meters. Maximum ambient temperature 40°C, minimum -15°C. Seismic zone 3 per UBC.
没错。现场海拔1200米。最高环境温度40°C，最低-15°C。按照UBC规范 为地震3区。
Looks good. Zhou, send us the updated spec sheet with the conversion table by Friday. Fatima, we're ready to move forward with the order.
看起来没问题。周工，周五前把更新后的带换算表的规格表发给我们。 Fatima，我们可以继续下单了。
Excellent. I'll prepare the final quotation based on these parameters.
太好了。我根据这些参数准备最终报价。
Site Inspection — Verifying Technical Parameters
Morning, team. Today we're running the performance test on Inverter #12. Chen, can you pull up the spec sheet so we can compare the actual readings against the rated values?
早上好，团队。今天我们对12号逆变器做性能测试。陈工，你把规格表调 出来，我们把实际读数跟额定值对比一下。
陈工: 好的。Inverter #12 is rated at 2.5 MW, maximum DC input voltage 1,500 V, MPPT voltage range 875 to 1,300 V, rated AC output voltage 690 V, 60 Hz.
好的。12号逆变器额定2.5兆瓦，最大直流输入电压1500伏，MPPT电压范 围875到1300伏，额定交流输出电压690伏，60赫兹。
I'll record the readings. What are we testing first?
我来记录读数。我们先测什么？
Let's start with the DC side. Connect the multimeter and measure the open-circuit voltage of the string.
先测直流侧。接上万用表，测下组串的开路电压。
陈工: 开路电压……Voc is 1,085 volts. That's within the MPPT range. Good.
开路电压……Voc是1085伏。在MPPT范围内。好。
Now measure the short-circuit current — Isc. Be careful, make sure you have the right range on the meter.
现在测短路电流——Isc。小心点，确认万用表在正确的量程上。
陈工: Isc is 14.2 amps per string. There are 28 strings in this combiner box, so total is about 398 amps DC.
Isc每串14.2安培。这个汇流箱有28串，所以直流总电流约398安培。
Cross-checking with the spec — the inverter's max DC input current is 4,200 amps. We're well under that. No overcurrent risk.
对照规格表——逆变器最大直流输入电流是4200安培。我们远低于这个值。 没有过流风险。
Good. Now let's look at the AC output. We need to verify voltage, current, frequency, and power factor.
好。现在看交流输出。需要验证电压、电流、频率和功率因数。
陈工: AC output voltage is 687 volts — that's within 0.5% of the rated 690 V. Well within tolerance.
交流输出电压687伏——与额定690伏相差在0.5%以内。完全在公差范围内。
Frequency?
频率？
陈工: 60.02 Hz. Dead on.
60.02赫兹。非常精准。
Power output is 2.48 MW. That's 99.2% of rated capacity under current irradiance. Not bad for late afternoon.
输出功率2.48兆瓦。在当前辐照度下是额定容量的99.2%。下午这个时间 段算不错了。
Let's check the conversion efficiency. What's the DC input power and AC output power?
我们算一下转换效率。直流输入功率和交流输出功率各是多少？
陈工: DC input: 2,535 kW. AC output: 2,480 kW. Efficiency = 2,480 / 2,535 = 97.8%. The spec says minimum 97.5% at rated load — we're slightly above that.
直流输入：2535千瓦。交流输出：2480千瓦。效率 = 2480/2535 = 97.8%。 规格书说额定负载下最低97.5%——我们略高于这个值。
Pass. Let me log it. I also want to check the temperature — the inverter casing should stay under 50°C per the spec.
通过。我记录下来。我还要查一下温度——按照规格书，逆变器外壳温度 应保持在50°C以下。
陈工: (points thermal gun) Casing temperature is 42°C. Ambient temperature is 28°C. Temperature rise is 14°C — well under the 25°C limit.
（用测温枪测）外壳温度42°C。环境温度28°C。温升14°C——远低于25°C 的限值。
Excellent. Humidity?
太好了。湿度呢？
Relative humidity is 35%. Spec allows up to 95% non-condensing. No issues.
相对湿度35%。规格书允许最高95%非冷凝。没问题。
Last check — measure the harmonics. Total Harmonic Distortion on the AC side should be less than 3% per IEEE 519.
最后一项——测谐波。交流侧总谐波失真按照IEEE 519应小于3%。
陈工: THD is reading 1.8%. Very clean output.
THD读数1.8%。输出非常干净。
Inverter #12 is fully commissioned. All parameters within spec. Sarah, mark it as "accepted" in the ITP. Chen, good work today. Let's move on to Inverter #13.
12号逆变器调试完成。所有参数都在规格范围内。Sarah，在ITP里标记为 "已验收"。陈工，今天干得不错。我们继续做13号逆变器。