Modular traction substation - traction substation (TP), consisting of separate transportable modules of full factory readiness, located inside of which the electrical and auxiliary devices are fully assembled, adjusted and tested at the manufacturer.
Content
Creation
Since 2000, on the instructions of the Department of Power Supply and Electrification, the development of a new installation technology for TP (complete-block or modular) has begun, which allows to substantially overcome existing problems, such as the long commissioning of TP (8-12 months), low operational reliability, large capital expenditures, large areas occupied by electrical equipment. The essence of this technology lies in the fact that research and design, design, production, testing, installation, commissioning, service and warranty service are carried out at one enterprise. The complete-block technology is based on the concept of creating a maintenance-free substation without permanent operational personnel, which is based on the following fundamental principles:
- use in the construction of new and reconstruction of existing substations highly reliable equipment that does not require the constant presence of staff on duty and whose maintenance is minimal
- the use of automation and functional diagnostics of all equipment of the substation, which allows you to move from service "according to the rules" to service "as needed"
The introduction of this technology allows you to:
- reduce the loss of electricity in the traction power supply system and improve the energy performance of the system;
- reduce maintenance costs by optimizing labor, energy and material resources;
- improve the reliability of all equipment and the safety of personnel;
Compared with stationary TP, complete-block traction substations have good mobility and implementation time, but there are still difficulties in installation, due to the fact that with the mandatory docking of the modules it is necessary to align them along the longitudinal axis, and also to perform sealing and insulation of joints. This, in turn, required high quality foundation performance and the introduction of complex support and adjustment equipment. In addition, the docking of the modules among themselves markedly reduced the indicators of fire protection, mobility, maintainability.
Modular type traction substation
Thanks to the improvement of the complete-block technology, some features of the installation of this substation appeared, which in turn made it possible to eliminate the drawbacks that had to be faced in the initial period of using the complete-block technology. All modules of the substation were supplied with non-removable insulated end walls on which bushing insulators connected to intra-modular power circuits and exit nodes of intra-modular secondary electrical circuits equipped with quick-disconnect connectors are mounted. Installation of the modules themselves is carried out in a specific order with gaps between adjacent modules.
Features
- Reducing the cost of construction work (minimum requirements are imposed on the foundation due to the lack of the need to align the modules along the longitudinal axis);
- ease of installation (no need to dock the modules together, therefore, no sealing or insulation of the joints between them is required);
- high mobility (quickly transported and installation of the substation takes place as soon as possible)
- fire protection (modules are provided with end walls and there is a gap between them, as a result of which, if a fire breaks out, the fire does not spread throughout the TP);
- maintainability (in the event of a module failure, it can be taken out of service, and a serviceable module can be installed in its place in a short time);
- placement of the substation in the designated area (due to the lack of module docking, they are not required to be placed along one axis).
Creating a set of integrated functional blocks of full factory readiness allows you to implement all the required types of substations and at the same time take into account the peculiarities of specific conditions in each individual case. Functional blocks can be placed in any "shell" - in a tunnel, a capital or pre-fabricated building, a metal or concrete container.
Functional blocks in switchgears
110 (220) kV open switchgear
The open switchgear 110 (220) kV is designed to supply step-down transformers and converters, it is used to power non-pulling consumers, high-voltage lines and transformers in the area. The circuit and design solutions of the switchgear for 110 and 220 kV are basically the same.
Busbars ORU build on reinforced concrete portals. All switching equipment: high-voltage switches, voltage transformers, current transformers, arresters - are placed on the same level. Installation of equipment should be performed taking into account the minimum distances between live parts, live parts and grounded structures, as well as the minimum safe distance to the parts that are under voltage.
In this switchgear, it is recommended to use gas-insulated core switches of the type VGT, VGU, VGG, gas-insulated VEB and VGBE tank switches, TG gas current transformers and NKF voltages, SFG disconnectors, RDP, with flexible busbars and rigid busbars.
27.5 kV AC Power Distribution Unit
An AC distribution device for a voltage of 27.5 kV (RU-27.5 kV) is used to power the traction AC networks.
RU-27.5 kV for receiving and distributing voltage of 27.5 kV from step-down power transformers, transmitting voltage to the traction network, to the two-wire-rail feeder supply circuit, to the own-needs traction substation, organizing ice melting and preventive heating the catenary wires, connecting filter-compensating devices.
Distinguish between RU-27.5 kV outdoor (OUT) and internal (ZRU) installation. LRU-27.5 kV can be gas insulated or air insulated. The installation of the traction substation consists in placing the blocks in a specially prepared area with foundations. The main advantages of the switchgear units are simplicity of design, installation, commissioning, operation and maintenance, availability of components for audits and inspections.
3.3 kV DC switchgear
DC switchgears for a voltage of 3.3 kV (RU-3.3 kV) are used to power the traction DC networks. They serve to receive 3.3 kV rectified voltage from the converter units, transfer voltage to the traction network, organize ice melting and preventive heating of the contact network wires, connect inverters, connect smoothing devices (filtering devices).
RU-3,3 kV is performed on the basis of functional units of full factory readiness.
Switchgear 6 (10) kV and switchgear VL signaling center
AC distribution devices for a voltage of 6 (10) kV (RU-6 (10) kV) are used to supply three-phase networks with insulated or grounded neutral. RU-6 (10) kV overhead lines of signaling centers are used to power the railway automation and communication devices. RU-6 (10) kV and RU VL signaling systems are also based on functional units of full factory readiness.
Recently, RU 6 (10) kV try to minimize the dimensions of the cells or chambers with high-voltage equipment due to reliable components, the use of new electrical insulating materials.
Rectifier Unit
The rectifier unit is implemented as a functional unit and serves to convert AC into a constant voltage of 3.3 kV in a six- or twelve-pulse rectification scheme in the traction power supply system of the railways.
The rectifier unit consists of two (1600 A rated current) or four (3200 A rated current) rectifier sections with a control, protection and alarm system.
Structurally, the functional unit has overall-connecting dimensions that easily ensure the installation of the rectifier units in the same row with the RU-3.3 kV with a common bus system.
The parameters of the selected elements of the rectifier sections are matched with specially designed for them heat pipes of the cooling system. This provides a high overload capacity of the units with natural cooling.
Protection from the network and circuit overvoltage episodic and periodic nature is carried out using RC circuits installed in parallel with the diodes. The voltage class of semiconductor devices used in the unit provides a fourfold voltage margin and ensures its operation even if one of the diodes connected in series in the rectifier phase fails. To protect against network and atmospheric overvoltage used nonlinear limiters.
When replacing the diodes, no special torque wrench is required, as the clamping mechanism used allows you to visually monitor the compression of the diode column with the necessary force, ensuring good thermal contact with the cooler and thereby the reliability of the instruments and the unit as a whole.
Proper Needs
The own needs of the traction substation include:
- functional unit of own needs of alternating current;
- functional unit of own needs DC.
Functional units of their own needs are finished products, have full factory readiness for turnkey deliveries and include switching equipment for 0.4 kV, 0.23 kV power circuits, protection, control, automation, measurement and signaling, as well as a controller, included in the distributed substation telemechanic system.
AC power unit
The own needs are designed to receive and distribute electrical energy of a three-phase alternating current with a frequency of 50 Hz, which consists of low-voltage distribution cabinets of 0.4 kV and a controller cabinet.
The modular, universal block building structure allows you to implement a circuit-based, functionally complete solution:
- with one or two input cabinets;
- with one or two backup input cabinets;
- with one or two power supply cabinets overhead lines;
- with any number of outgoing feeder cabinets.
As historians of the main auxiliary power supply, auxiliary power transformers (TCH) with a capacity of up to 630 kWA are used. As backup power sources can be used:
- backup TSN;
- diesel generator;
- uninterrupted power supply unit.
In normal mode, one input is enabled, the second is in reserve.
DC power unit (CH)
The CH unit is designed to power the responsible consumers of the traction substation (automation, control, protection circuits). Together with a rechargeable battery (AB) and charging rectifying devices (SLE), the unit forms an uninterrupted power supply system for consumers with direct current.
DC unit DC provides measurement:
- voltage on tires + ШВ and + ШУ;
- charge current - discharge AB;
- current consumption circuits + SHU;
- busbar insulation resistances with alarm status.
DC block DC includes:
- cabinets of distribution external connections in which all necessary switching equipment is placed;
- Charger.