To solve the long cable issues an unprecedented challenge!To give full play to the advantages of sumitomo electric group and synergies ~
Provide breakthrough wire manufacturer scope of business solutions
East Japan earthquake as an opportunity, the power industry in the "renewable energy application expand" a sign of this structural change.In this context, the new renewable energy service providers to sumitomo electric group of customers with high hopes, that in addition to provide cable, also offers, including system design, power transmission and transformation solution to power grid to power system.
While keep the subject consciousness, sumitomo electric start and service provider in the high-profile GPI in talks.The negotiations of the parties is now power projects department technicians long really fix two mountains.About 5 years ago, GPI around the tsugaru wind farm has carried on the concrete discussion.
"I tried and there is no relationship of GPI, make an appointment at that time, finally had the tranship wood minister held talks GPI President (now).Initial difficulty is how to make each other understand the company's vision, I recalled.But through effort to GPI said after considering the solution of our group, the other party put forward 'to electrical design business to sumitomo electric industries', this sentence makes me very grateful.In this context, we with the production of the substation equipment of the new motor corporation and sumitomo electric set focus on electrical engineering co., hand in hand, in order to ensure the company related business group that cover all of the power transmission and transformation equipment, from the company's core staff seconded concurrently hold the post in the project, build the system of horizontal collaboration.Since then, the company on the basis of electrical class overall design, to the application for approval to assist and path to explore invested a lot of energy, and construction.The project always accompanied by worries: the process from inexperience of substation and civil engineering, can complete the whole project design?Can be completed in two years time such a long line?But in three engineers in the process of in-depth discussions, we gradually believes he can do it, and pay attention to the solution of great value, and this solution is not simply provide the company's products."(true)
Long distance transmission, transmission loss and the path chosen in the process of subject
Tsugaru in the construction of the largest domestic onshore wind power station wind farm, in the process of China, there is no precedent.Its design scheme is: through the 33 kv underground distribution circuit of the power of wind station collector, step up to 154 kv, in the form of underground transmission, send its to electric power company (northeast power Network corporation) substation, the segment transmission distance is about 34 km.Was responsible for power transmission and transformation equipment related business director, now mayor of wire/energy business headquarters technician was a male said: "as long as the size of the underground long distance transmission project of 34 km are difficult to imagine at the time."
"34 km is equivalent to the distance between Tokyo and yokohama.Transmission losses is one of our subject.So we change the voltage of the scheme was proposed, that is, from the initial plan of 66 kv power transmission changes for 154 kv power transmission.This is a reasonable scheme based on electrical principle, compared with 66 kv power transmission and transmission losses.In addition, it also reduces the number of laying cable, realize the lightweight, which helps to reduce pipeline civil engineering quantity, can promote the bridge cable add * interoperability.But it highlights a new great subject that must be solved long cable grid to the strange phenomenon happens when power system (voltage fluctuation and high order harmonic resonance phenomenon, etc.).According to these strange phenomena, needs to consider the electrical properties of the cable and substation machine design, this is a challenging job."(field)
Strange phenomenon can be expected as described later, there are five (5).To solve these strange phenomena, sumitomo electric industries, such as too field challenge with the technical personnel of the new motor ・ system engineering of plant hao village.In order to build up the most suitable for electrical system, with the power companies for technical consultation, design, production machinery, supply and installation, etc., as the wind power key to power transmission and transformation equipment, plant village to shoulder the "smoothly and rapidly promote the project" the function.So what are the strange phenomenon caused by long cable?
* refers to the cable to add in road and bridge (bridge steel bridge/PC).
To understand and ultimately solve the "five strange phenomenon" is the biggest issue
"In the career, need to deploy to average factory or building with power transmission and transformation equipment is difficult to imagine of long distance high voltage cable.Strange phenomenon happens due to transmission, so electricity company requirements with respect to its applicability to fully explore beforehand."(village) graft
Most strange phenomenon beyond the sumitomo electric group has so far been the scope of the accumulated knowledge and experience.According to these strange phenomena, takes the countermeasure of how to?Plant village said:
"Buried in the ground of the cable due to its structural reasons, compared with the overhead transmission line, savings in power cable is very big.We call it the static capacity or the charging capacity, it would be great in the long cable.This is the reason why cause 5 strange phenomenon.We discussed repeatedly for each phenomenon, finally the solution is obtained.
1 point is that the ground short circuit accident leakage (high voltage), the effect of blocking operation for the accident.cable中所积蓄的电与事故电流一同流入，使事故电流增加，进而导致无法正常阻断事故的可能性。为了用反向电流来抵消从该电缆中流入的电流，在变压器的中性点设置了补偿电抗器。
Second point is that the deviation caused by the charging capacity of the cable and the voltage fluctuation range stipulated in the electric power company.Set to split a long cable for this grid that open and close, and install the device that is used to offset the charge of the cable capacity, namely the shunt reactor.
Third point is that because of the overvoltage caused by damage to the machine.Even open substation circuit breaker to stop the power supply, due to the electric cable (charge) the characteristics of residue, thus to close the circuit breaker, there is damage to the machine.For that matter, with a discharge device (grounding type machine) to deal with, but also the fact that the normal discharge, problem has been solved.
4 points are, the harmonic resonance.Harmonic is refers to the commercial frequency (50 hz / 60 hz) five times the ・ 7 times, such as frequency, due to there is originally don't need normal electrical waveform distortion.Long the electrostatic capacity of the cable and the loss of balance between power system (inductance) and produce resonance phenomenon, power system harmonic within will increase, there will be the machine such as the possibility of overheating.In this case, set the harmonic filter is used to suppress harmonic resonance.
5 points are, due to the setting of neutral point compensation reactor or caused by the influence of shunt reactor zero passage phenomenon.Refers to the phenomenon, when the electric accidents, accidents of electric current and usually ac waveform is different, but like dc become cross with zero phase state.Into this state, will not be able to block fault current, there is the possibility of damage to the circuit breaker.Therefore, adopted such as increase the resistance of the neutral point compensation reactor, advance of shunt reactor blocking, etc countermeasures."(village) graft
The move began in March 2017, after several times after consultation with electric power company, in the same year December have won approval to electric power company.After nine months, finally realizes the tsugaru wind power plant and the interconnection of power system.
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