| category | Natural power factor | Harmonic content | Mechanical properties | Unit maintenance | fabricating cost | Managing effect |
| Dc drive LDB rig modular network system | Very lower | Higher | Best | General | more | Better |
| Ac drive LDB rig modular network system | Lower | Lower | worse | Lower | Less | Good |
| Variable frequency drive LDB rig modular nets electric system | Higher | Higher | Better | Lower | Most | Better |
1.System components:
Dc drive LDB mechanical and electrical power system is a composite drilling in the original mechanical chain transmission network, and on this basis to the power grid as a power supply substitute diesel generator, hydraulic coupling unit alternative diesel engine dc motor drive directly chain transmission and torso. The drilling network system is made up of nine compounds, including 10KV grid, 400V generator, and MCC room, one KP module with 600V network high-voltage distribution, one transformer KT module, two DC units’ modules ZD and carriage. For part of the drilling rig, some equipment as top-driven VFD room, electric pump VFD room, 600V generator etc.
2.Application
This network system is suitable for network transformation project of ZJ50LDBand ZJ70LDB compound drilling rig, is also suitable for network transformation project of ZJ40J mechanical drilling rig. After using this product, drilling rig no longer use diesel engine and diesel generating set but DC motor hydraulic coupler set driven by power to drive carriage directly, use network to drive other equipment in well site, thus lower diesel consumption of high price, reduce CO2 emission and greatly lower noise of well site.
As a result of its excellent speed regulating characteristics of DC motor excitation, the network system can adapt to all drilling conditions, especially under the condition of low speed and high torque, its efficiency is much higher than the efficiency of diesel engine. Therefore, doing network transformation to LDB drilling rig, the effect of energy saving and emission reduction is particularly evident. According to our tracking statistics, The direct benefit of LDB network transformation is able to reduce (45 to 65)% drilling energy consumption cost, if the cost, like operation, maintenance, spare parts, fuel oil transportation etc of diesel generating set is accounted, the overall reduction of drilling power cost is around （50 to 70）%.
3.Basic mechanical design feature
The network high-pressure room is consisted of network transformer module KT and 600V power distribution compensation module KP. According to the different needs of drilling conditions, you can adopt different KT, KP combination. Network high-pressure room can common used in LDB rig’s transformation with network controlling module (including DC speed control, variable frequency speed regulation and soft start module), moreover you may also make a renovation to full electric drill’s network alone. The main technical parameters see table 1 and table 2.
Table 1 High-pressure room main technical parameters |
| essential parameter |
| Model | DH.KYB1F-10/0.6 | Transformer capacity | 1600～3150 kV |
| Max. rated voltage | 12kV | Capacity of MSVC | 1005～1615kVAr |
| Rated operational voltage | 10kV | Harmonic compensation current | 200～600A |
| Shell coefficient | K=10 | Dimensions | L1150*W2900*H2940 |
| Protection level of distribution room | IP55D | Total weight | 26t |
| The default configuration main parameters of transformer |
| HJB | SCZ10-2500-10/0.6 | Rated capacity | 2500kVA |
| On-load changer range | 10±4*2.5%/0.6kV | Impedance voltage | 6.0% |
| resistance to heat class | H | Winding coupling group | D,d-0 |
| high-voltage switch cabinet main parameters |
| Model | TZ.XGN1-12/630-20 | Rated voltage | 10kVA |
| XGN15-12FV/630-20 | Rated current | 630A |
| Rated short-circuit breaking current | 20kA | Short-term resistance current | 20kA/4s |
| Table 2 Different rig and transformer capacity, reactive power compensation and harmonic compensation current capacity supporting table | |
| Rig model | 70LDB | 50LDB | 40L | |
| Transformer capacity (kVA) | 31500 | 2500 | 2000 | 1600 | 1600 | |
| Reactive power compensation capacity (kVAr) | 160 | 1200 | 1005 | 1005 | 1005 | |
| Filter harmonic compensation current (A) | 40 | 300 | 200 | 200 | - | |
Network SCR electric control room, namely the network DC control module KZ, by a separate room body structure, with DC motor unit hydraulic coupling ZD common used in LDB rig network reconstruction project. The main technical parameters see table 3.
| Table 3Network DC control room KZ main technical parameters |
| Model | DH.KZ1-0.6/0.4 |
|