Going up to the 20th floor, the access control is closed and you can't go up. Yonghan and Fu Shuo walked from the passage to the building next to the mountain. This building is built on the mountain, but it is not close to the mountain. There is a distance from the mountain and is connected by several passages. These connecting walkways can go up to the mountain and also play a role in strengthening the building.
Yonghan's buildings on the mountain reach the highest point. Looking at the moment when the wind strength decreased, it should be at the eye of the typhoon, and walked through the walkway to the roof of the commercial building.
At this time, the wind suddenly increased again.
The roof of the building is filled with water, like a swimming pool. The skylight above was open and leaking, and the door below had a small gap. This way more water comes in and less water comes out. There is a lot of water on the roof of the building.
Yonghan said: "Fu Shuo, you can take out the rubber boat this time. It will come in handy this time."
Fu Shuo took out the rubber boat and said, "I didn't expect to row outside the building and on the roof of the building."
"I was going to swim there. Fortunately you brought a rubber boat."
The rubber boat uses an automatic inflating device. It will be automatically inflated after being put down for a while. He pushed the rubber boat into the water, shook the paddle, and rowed towards the central power distribution room.
Shi Qiubing and Qu Fei walked around to the top of the mountain and came to the cave. Shi Qiubing said: "There is also a backup power supply here."
Qu Fei asked: "Why is there still power here?"
Shi Qiubing said: "In order to prevent the building from losing power, there is also a small transformer here."
Qu Fei said: "Let's go to the commercial building opposite."
At this time, I found that the wind in the aisle was too strong. The wind carried the rain almost sideways through the windows.
Qu Fei called Yonghan and said, "Have you reached the top of the building?"
"Yes. We are on the roof of the building, near the power distribution room. We will check the power system of the wind power device later."
Qu Fei said: "We have reached the top of the mountain, let's go over and help."
Yonghan said: "No need to come over. Let us check first. Maybe it will be fine just to connect the power supply."
Yonghan began to check the power system.
The wind power device is driven by an AC motor, and the AC motor is driven by an AC-DC converter. Frequency converters include AC-to-AC frequency converters, AC-to-AC frequency converters, etc. The frequency converter outputs three-phase alternating current with a phase difference of 120 degrees.
The AC inverter directly generates the required variable voltage and variable frequency power supply by controlling the three-phase industrial frequency power supply through several groups of phase-controlled switches. Its advantages are high efficiency and the energy can be easily returned to the power grid. Its biggest disadvantage is that the maximum frequency of the output must be less than the input power supply. One-half of the frequency, otherwise the output waveform is too poor, the motor will vibrate and cannot work. Therefore, the AC inverter is limited to low-speed speed control situations, which greatly limits its scope of use.
The use of voltage-type AC-DC converters, a rectifier frequency converter, has excellent features such as simple structure, low harmonic content, and adjustable stator and rotor power factors. It can significantly improve the operating status and output power quality of doubly-fed generators, and this structure The grid side and rotor side are completely separated through the DC bus side capacitor.
The main circuit of AC-DC-AC frequency converter consists of three components: rectifier circuit, intermediate circuit and inverter circuit.
Yonghan checked these parts one by one.
The rectifier circuit is the power conversion part that provides voltage-regulated and frequency-modulated power to the asynchronous motor. It is a frequency converter that converts the DC voltage source into AC. The filter element of the DC circuit is a capacitor. Yonghan uses a signal generator to simulate voltage input, and the output voltage is normal.
Intermediate circuit, converter of rectifier diodes, which converts power frequency power into DC power. Two sets of transistor converters can also be used to form a reversible converter. Since its power direction is reversible, it can perform regenerative operation. Yonghan uses a signal generator to simulate voltage input, and the output voltage is normal.
The inverter is the opposite of the rectifier. The inverter converts DC power into AC power at the required frequency. By turning on and off six switching devices at a determined time, a three-phase AC output can be obtained. Yonghan used a signal generator to simulate the voltage input, but there was a problem with the output voltage. The three phases were asymmetric. He replaced the switching device, and when tested again, it was normal.
But the wind turbines are not working and power has not been restored.
"The power supply system of this building should have been short-circuited."
"What should we do?"
"Go to the first floor and connect the power directly from there."
At this time Qu Fei called: "Has your power been restored?"
"No, I plan to go down."
Qu Fei was unhappy and said, "Why don't you ask me why you came to the north of the mountain?"
Yonghan heard that Qu Fei was unhappy, and knew it was too late to ask, but still asked: "Why?"
"Because there is a power supply system here, it is to prevent power outages in commercial buildings."
"Okay. There's electricity over there, I'll go get it."
But it was very windy and rainy outside. The whole person may be blown away.
Shi Qiubing quickly assembled the kite.
This is a hard-winged kite. Its characteristic is that the lift piece is made of two horizontal bamboo strips up and down into the shape of a wing. The edges on both sides are high and the middle is concave to form a ventilation channel. The ends of the wings are tilted backward to allow wind to escape from the ends of the wings, making them look like ingots when viewed flat. For example, the popular rice-shaped kites, flower baskets, mandarin ducks, magpies, parrots, etc. in Beijing have fixed wings with fixed wings.
There are two wind sensors under the wings of the kite to detect the strength of the wind. There is a small motor that can adjust the posture of the wings in a small range.
Shi Qiubing said: "With this, the kite flies over with the wires here, so that the cave power supply can be used to power the wind power installations in commercial buildings."
However, the wind is now blowing to the west, not to the south.
How to convert the force blowing westward into the force blowing southward? Do you use your own wings as a kite? In this stormy weather, it is difficult for a kite or even an airplane to control its direction.
Shi Qiubing thought that wires could be tied to the kite, and the kite would blow westward according to the force of the wind. One end of his hand is pulling the wire, and under the action of the pulling force, the kite moves west to a certain position and then starts to move south, and then rotates around the building to form a spiral trajectory, so that it goes around the east and north sides of the building. .
The kite starts from the north, goes west, south, east, and finally circles the building and returns to the north. Yonghan and Fu Shuo caught the kite and the wires on the kite.
The roof began to leak. The power control system was blown into a mess, but the power cabinet was not opened. We had to find something to keep out the rain to prevent water from getting inside.
Yonghan looked around and took out several solar panels to make them into rainproof boards. Under the weatherboard, connect the wiring.
The power supply was restored, the wind generators were activated, and the city's four wind generators generated anticyclones, gradually canceling out the original typhoon. A tin trash can was blown into the air, and suddenly it seemed to have lost its lifting power and fell down again.
The heavy rain also gradually stopped.
After the rain, the weather cleared up. In the Yishan building, the decorations and items on each floor were almost packed away. Yonghan sat down and chatted with Qu Fei, "Sorry, next time we go on a mission together, I will ask you if there is any other way. Fortunately, the main part of the building has not been destroyed. I can buy you a drink this time. It’s tea.”
"You should have invited me a long time ago, before the typhoon came." Qu Fei said with a smile.
Yonghan said: "It's not too late now. I'll wait for the meal Ying Yang owes me tonight."
