[单选题]高压试验与测量工作中，变更接线或试验结束，应断开（），并将升压设备的高压部分放电、短路接地。
A.试验电源
B.设备电源
C.上一级电源
D.测试电源

Current Group, a Germantown-based technology firm, has taken over an ordinary looking house in Bethesda and turned it into a laboratory for smart-grid technology, the system the company believes will bring the nation’s electricity grids into the digital age.
In the front yard stands a utility pole hooked up to a special transformer that connects the power lines to high-speed Internet. Hundreds of sensors attached to the lines monitor how power flows through the home. That information is then sent back to the utility company.
The process lets a utility more efficiently manage the distribution of electricity by allowing two-way communication between consumers and energy suppliers via the broadband network on the power lines. Based on data they receive from hundreds of homes, utilities can monitor usage and adjust output and pricing in response to demand. Consumers can be rewarded with reduced rates by cutting back on consumption during peak periods. And comput
A. Computers and Internet bring utilities into digital age
B. A new technology is introduced into the nation’s electricity grids
C. The U. S. government will work with a private electricity company
D. Smart-grid technology will take the place of coal or gas based power plant