Introduction

1. Overview

HGIS(Hybrid Gas Insulated Switchgear)is a new type of high-voltage switchgear. With the advantages of GIS, such as compact structure, high reliability and low maintenance requirements, HGIS adopts also the conventional AIS way of busbar connections to the GIS, and has smartly overcomes the disadvantages of the conventional AIS equipment, such as large floor space requirements, a lot of connecting points and heavy workload in overhaul and maintenance. This product is very suitable for use in power transmission and distribution systems with system voltage not higher than 145 kV, such as power plants, substations, railway, harbors, heavy industrial and mining, this product is ideal for projects having floor space limitations, such as substation in mountainous region and urban areas. The HGIS equipment can be installed indoor, outdoor or even on top of the roofs.

2.Product advantages

ZHW13-126 (145) Hybrid Gas Insulated Switchgears (HGIS) are configured by different standard functional modules, namely, circuit-breaker, combined disconnector/earthing switch, current transformer, voltage transformer, etc.

Comparing with the GIS and AIS, the HGIS has the following advantages:
● High reliability in operation, low workload in overhaul and maintenance (maintenance free for 25 years);
● Can be directly installed outdoor, and requires very simple civil construction and electrical installations, simply plug and play;
● Low SF6 gas consumption (only 20% of the consumption of GIS), thus it is more environmental friendly;
● Low life cycle cost;
● Small in size, light in weight (by using silicon rubber bushing and aluminum tank), high performance in anti-contaminated, water-proofing, and anti-vibration;
● Short installation time, high reliability, suitable for extension and retrofit projects of power plants and substations.


A three-position disconnector and earthing switch will be placed in front and rear side respectively, which makes HGIS become an individual working unit. Hence, it's unnecessary for HGIS to be equipped with extra three-position disconnector and earthing switch. Owing to the modular design, different group number of three-position disconnector and earthing switch can be provided on customer request. Voltage transformers, surge arresters and other components are also optional.

3.Normal operating conditions:



4.Protection class and pollution level

The protection class of HGIS is IP54; the pollution level is Grade IV.

5.Construction

Three phase separate enclosure

Main features of HGIS

ZHW13-126 (145) /3150-40 Hybrid Gas Insulated Switchgear

is a kind of compact high-voltage switchgear. This equipment has combines the advantages of both the air insulated type and the gas insulated type switchgears, and has adopts the most advance world leading technology and manufacturing processes to integrate all the high-voltage components to a very high extend, making the product highly compact and highly reliable.

1.Thoroughly solved the operation reliability problem of the disconnector/earthing switches

HGIS adopts a new type of totally SF6 sealed disconnector/earthing switch, which can protect the contacts from the external environmental conditions, the excessive temperature rise cause by contacts erosion by the atmosphere can be avoided. In addition, the new clipping contacts design of our HGIS can provide lower contact resistance and higher current carrying capacity.

From mechanical design point of view, our HGIS is using the latest design concept , the combined disconnector/earthing switching system in a module. The three-position (DS Closing – DS Opening – ES Closing) disconnector/earthing switch can prevent the operators from connecting the live part to earth or any other mal-operations. This design can also reduced the overall dimensions of the switchgear to a very high extend, and in addition to that, the mechanical structure and secondary control circuit is getting simpler, so as to provide higher reliability.

The switch has a fully enclosed mechanism with three positions, with mechanical endurance (without connecting primary equipment) up to 100,000 times. This advance design can also allow the equipment service continuously under the rain; and in addition to that, replacement of mal-functioning parts can be done within a very short time, in less than an hour.


2.Advanced self-blast arc extinguishing principle and modular design structure provides higher reliability

HGIS circuit breaker operates by means of the well-known self-blast principle, as the energy for interrupting the arc is partly supplied by the arc itself, therefore, reduce the mechanical driving force requirement from the operating mechanism. The lower mechanical driving force requirements provides the following benefits, including but not limited to, reduce the mechanical strength requirements of the mechanical parts, reduce the overall dimensions of the equipment, lower the manufacturing cost, lower the mechanical shocks and operating noise, therefore improves the mechanical endurance and reliability of the equipment. The self-blast arc extinguishing design can provide also extended electrical life as high as 40kA full capacity breaking for 20 times, our new type spring operation mechanism is used, allowing the mechanical life to reach a new level of 60,000 times. Our advanced design and manufacturing process can allow our equipment to be operated continuously under 100% humidity.


3.Require no or less disk insulator provide higher reliability

HGIS adopts the most common single-busbar modular design; each phase (bushing-bushing) is an independent gas chamber, and they require no disk insulator as partition. Disk type insulator will only be required for PT, cable terminals and double busbars, only one disk insulator will be required for each phase. Comparing to the GIS, the amount of disk insulators used in HGIS can significantly be reduced, therefore the overall weight of the HGIS can also be reduced. More importantly, the number of insulating sections and gas sealing parts are reduced, therefore, the overall reliability of the equipment is improved and in case of any internal failure, the fault can be located much easier.

4.Using special technology to reduce the number of flange, so as to minimize the possibility of gas leakage

The unique manufacturing process of our HGIS has adopts the most advance aluminum tank fabrication technology which can reduce the possibility of gas leakage to the lowest possible extent. And when comparing to similar products in the globe, our product is more attractive in appearance and lighter in weight.


Main features of HGIS

5.External CT, safer and more reliable

Our HGIS use the externally installed core type CT, the CT in cylindrical metal enclosure is mounted onto the metal pipe of the switchgear equipment, by using core type CT we can eliminate the possibility of primary insulation breakdown of the CT and the risk of the burning out the secondary winding due to the overheating of the primary circuit of the CT. On line replacement of the CT is also possible and the replacement process is very simple.

 

6.Compact structure, flexible layout

Each HGIS bay is produced in the factory as an independent module, the HGIS bay is delivered to site in one piece. The module (HGIS bay) is supported by two metal frames; the leveling and positioning requirements among the bays is not as strict as those required for the GIS installations. Comparing to the GIS the floor loading requirement for HGIS is also much lower.

Each HGIS module is delivered to site as a complete switchgear, in one piece, the installation procedure is as simple as: positioning of the metal supporting frames, positioning of the module, connecting the control cable plug; the amount of site installation work is lowered to the lowest extend.

Light in weight, compact design, simple foundation requirements, easy installations are the features of our HGIS, this can allow very flexible arrangement of our switching bay layout design, especially for some special application such as mobile substations, roof top installations etc. HGIS is the best choice and the best solution.


7.Investment comparison among HGIS, GIS and AIS

In terms of service performance, the reliability and the convenient in maintenance of the HGIS is similar to that of the GIS, however, from return on investment (ROI) point of view, HGIS is worth promoting. When we take a 550kV 3/2CB Comparing among the HGIS, GIS and AIS, the price of HGIS is 53% lower than GIS, and 1.5 times that of AIS. Taking the cost of land and civil construction cost into account, the total investment of a substation is expected to be 45-50% lower than that of GIS, and only 15-20% higher than AIS.

For a HGIS bay with the same specification, the longitudinal dimension of HGIS equipment is much smaller than that of AIS equipment, therefore saving 40-60% floor space. On the other hand, HGIS can save over 30% investment compared with the GIS. For those substation projects having problem in using AIS due to limited space problem and they have also problem in using GIS due to budget problem, decision to use HGIS can provide users with a perfect solution that is very suitable for the Chinese conditions and can significantly reduce the workload and difficulty in design and construction. As a result of the higher product reliability and lower product maintenance workload thanks to the new structure and technology, HGIS can offer more convenience in application and maintenance, therefore realizing a higher performance price ratio.

Comparison among GIS, HGIS and AIS



Digital HGIS solution

We can provide the traditional control and protection solution for our HGIS, and we can also provide our digital solution.

Along with the development in computer and electronic technology, the web base technology can now fulfill the real-time control and reliability requirements for protection and control, and now the very matured electronic technology development can fulfill the severe service condition of the instrument transformers and switches, etc; the totally digital solution can realize the information exchange between equipment types, digital processing of the information and digital command being sent to the equipments.

Digital substation means within the substation, data collection, communication, processing and command are all in digital form; basically all equipments are digital, network base communication, and automation control.

Digital primary equipment

Some intelligent primary equipment including electronic instrument transformer, intelligent switch (or conventional switch equipped with intelligent terminals) are used. Exchange of information including sampling value, status variable and control command etc. between the primary equipment and the secondary control equipments are being handled by fiber optics in digital coding.


Networking of secondary equipment

Secondary equipment adopts communication network to exchange information including analog variable, switch variable and control command etc., no control cable will be required.

Automation of operation and management system

Should includes systems such as, fault analyzer, self diagnosis as well as programmable control system, etc., all these can improve the automation level as well as reducing the work load and difficulties in operation and maintenance.

Advantages of digital HGIS:

1.Various functions of the substation can share a common information platform, so as to avoid the repeated investment in equipment.

All communication of the digital substation is using a common communication protocol and being connected to the communication network using the same standard. The various system used in the substation, such as protection, data acquisition, monitoring, command, metering, control and VQC etc are using the same communication network to receive the information on current, voltage, status and send out control command, it is not necessary to installed different data collection, communication and execution system for different substation equipments.

For conventional substations, different equipment is using its own information collection and storage system with different communication protocol. Control cables are being used to transmit analogue and voltage signals among the primary and secondary equipment, different equipment has to set up their own data collection, transmission and execution system, this makes the substation control and signaling system more complicated and with higher cost.

2.Convenient for the substation to be extended and the adding in of new functions

Information exchange between the equipment of digital substation is supported by the communication network. When the function or the scale of the substation has to be expanded, in the case of digital substation, the newly added equipment simply plug onto the communication network without the need in changing or replacing the original equipment. So, the end-user’s investment can be guaranteed and the overall life cycle cost of the substation can be reduced.

The data collection, processing and command output functions within a digital substation are being handled by different system. When new functions have to be added to the substation, if there is still capacity in the respective systems, no extra hardware investment will be required.

3.Communication network replaces complicated control cable

Computer communication technology is adopted by the primary and the secondary equipments in digital substation, information exchange among the different equipment can be handled by one communication channel, network communication technology is adopted. The number of communication line required is equal to the quantity of equipments; therefore, the secondary wiring in digital substation can significantly be simplified.

4.Improve the measurement accuracy

In digital substations, the output signal of the electronic current and voltage transformers are in digital form, when the digital signal are sent to the secondary control or protection devices, there will be no tolerance, this can improve the accuracy of the measurement, protection and tariff system.

For example, if we are using accuracy grade Grade 0.2 TA and TV in conventional substations, the additional error brought about by cable and metering leads to a total metering system accuracy level of ±0.7%. For digital substation, the error of metering system only comes from TA and TV; therefore, it is just at the level of ±0.4%.

5. The reliability of signal transmission is promoted

Computer communication technology is applied in the signal transmission in digital substations. The communication system while transmitting the information is sending out also the check code for the data transmitted as well as the self diagnosis signal for the communication channel, this can avoid the possibility of wrong signal transmission and at the same time warning signal can be given when there is any failure in the communication channel or the communication system. The digital signal can be transmitted by using the optical fibers, interference can be avoided completely.

In conventional substations, signal transmission between primary and secondary equipments is realized by using the control or signaling cables, signal checking by using check bit is not possible, and when the signal is wrong, or when the cable carrying the signal is open circuit or short circuited, it will take time to find out. Analogue signal is subject to external interference, and using of optical fiber technology to transmit the analog signal is not possible.

6.Electronic transducers are used to resolve the inherent problems of conventional instrument transformers

Electronic transducers are used in digital substation, therefore the inherent problems of the conventional instrument transformers can be avoided, such as over voltage risk due secondary winding open circuit in case of CT, impact of TA saturation causing differential saturation, impact of CVT transient state process on distance protection, magnetic core resonance, insulating oil breakdown explosion, and SF6 gas leakage, etc.

7.Problems arise from electro-magnetic interference, transmission overvoltage and two earthing points

Fiber optic communication cable is used for the communication connection between the primary and secondary equipment, therefore, electro-magnetic interference causing the overvoltage in the signal transmission cables can be avoided, and we don’t have to worry about the way of earthing connection of the signal transmission cable.

The secondary and primary equipments of the conventional substations are still using cable connections for signaling and control, therefore the control cables could pick up electromagnetic interference as well as the transmission overvoltage in primary equipment which in turn may cause the abnormal operation of the secondary equipment. In case of long secondary cable, the interference of capacitance coupling may lead to the malfunctioning of the relay protection. Despite the requirement of one-point earthing in relay protection secondary circuit specified clearly in the relevant specifications of power industry, however, it is difficult to locate the exact earthing location for secondary control circuit. So, two-point earthing in secondary circuit occasionally happens, which generates adverse effect on relay protection and even leads to the malfunctioning of the equipment.

8.Problem about interoperation between equipments is resolved

All the intelligent equipments used in the digital substation are using a standard communication protocol, all the equipment can be connected together and can communicate among each other.

The only standard communication protocol used in the digital substations is IEC 61850, equipment supplied by different manufacturers can be connected together, information can be exchanged and the higher level equipment can control the lower level or downstream equipments.

In conventional substation, problem in communication cannot be solved completely. Equipment supplied by different manufacturers are not having the same or a standard communication protocol, a lot of protocol converting work has to be done to connect the equipment together, this make the system design more complicated and making the commissioning, operation and maintenance work more difficult, the performance and reliability in communication is low.

9.Enhancing of the automation and substation management level

When intelligent HGIS equipments are used in the digital substation, the HGIS can be controlled from remote. The information transmitted by the communication system is complete, and the information is reliable and real-time. Therefore, the substation can applied with more automatic functions and more complicated automation operations; thus enhance the automation level of the substation. The HGIS equipments, secondary equipments and communication network are having self-diagnosis function; maintenance will only be required according to the health conditions of the equipments.


Key technical data of the product



Technical data of the circuit-breaker


Friendly reminder: The data and illustrations contained in this document are provided for information only. XuJi (Xiamen) reserves the right to revise or change these data and illustrations at any time without further notice. Please contact our engineers concerned for the latest brochure.

Application examples