13 power distribution and consumption technologies have entered the "Catalogue of New Technologies Promoted by Power Grid Companies (2017 Edition)"

The power grid company recently released the "Catalogue of Promoted New Technologies by Power Grid Companies (2017 Edition)". Based on the principle of "widely applicable and significant impact", the "Catalogue of Promoted New Technologies by Power Grid Companies (2017 Edition)" summarizes and refines the technological development needs and new technology achievements of the power grid, building upon the 2014 edition. This article is an excerpt and sharing of new technology projects for distribution and electricity consumption promotion.

The "Catalogue of New Technologies Promoted by Power Grid Companies (2017 Edition)" includes 13 items in the distribution and electricity consumption section: environmentally friendly gas-insulated metal enclosed switchgear, transient recording type fault indicator, distribution automation terminal security protection technology, distribution automation technology, energy-saving distribution transformer, intelligent distribution substation area, distributed power grid-connected equipment and system, 35kV integrated substation, secondary circuit state detection technology of current transformer, composite material cross arm, object-oriented electricity information data exchange protocol, intelligent electric energy meter software detection technology, and online metering and intelligent diagnosis technology.

Environmentally friendly gas-insulated metal enclosed switchgear I. Technical principles and characteristics

Environmentally friendly gas-insulated metal enclosed switchgear refers to a metal enclosed switchgear that utilizes environmentally friendly gas as the main insulation, employs vacuum arc extinction, and has all high-voltage live parts (excluding incoming and outgoing line devices) enclosed within a metal enclosure at a micro-positive pressure (≤0.04 MPa). It is supported by a small amount of solid insulation material, has a continuous operation capability not lower than LCS2A, and possesses the ability to normally interrupt rated short-circuit faults under zero gauge pressure conditions.

Environmentally friendly gas-insulated metal enclosed switchgear can be divided into two major categories based on its application function: ring main unit (RMU) and switchgear (gas-filled cabinet, C-GIS). They primarily use dry air, pure N2, or other synthetic environmentally friendly gases as the main insulation, which can fundamentally eliminate the dependence on SF6 gas, and their manufacturing costs are comparable to those of the original SF6 gas-insulated metal enclosed switchgear. There are mainly two types of structures: European and Japanese. The gas box of the European structure is welded with thin metal plates, with a simple manufacturing process that can ensure the stability, consistency, and operational reliability of product quality during mass production. The Japanese structure uses thick metal plates for welding, resulting in a large volume, outdated anti-corrosion treatment process, and complex mechanical interlocking of the entire machine. Domestically, the European structure is mainly adopted, using dry air or pure N2 as the main insulation for environmentally friendly gases.

Compared to open-type air-insulated metal enclosed switchgear, the environmental protection gas-insulated metal enclosed switchgear can reduce equipment footprint by over 50%, enhance safety by 70%, improve resistance to harsh operating environments by over 90%, and reduce maintenance costs by over 80%. Compared to SF6 gas-insulated metal enclosed switchgear, it offers an environmental protection improvement of over 10,000 times, significantly enhances safety, effectively reduces the total life cycle cost (LCC) of the equipment, and produces and emits no inhalable particulate matter, toxic gases, or greenhouse gases during production and operation, resulting in a high ***.

II. Applicable conditions

(1) Regions with high requirements for environmental protection and power supply reliability;

(2) Regions with harsh operating environments (coastal areas, humid environments, high temperatures, severe cold, high altitudes, areas with corrosive chemical gases, or heavily polluted regions, etc.);

(3) Remote areas with poor transportation and inconvenient logistics, making it difficult to conduct patrols and maintenance;

(4) For rated currents of 630A and below, and breaking currents of 20kA and below, it is advisable to prefer environmentally friendly gas-insulated metal enclosed ring main units; for rated currents above 630A and breaking currents above 20kA, it is advisable to prefer environmentally friendly gas-insulated metal enclosed switchgear.

III. Promotion and Application Plan

From 2016 to 2018, we began to gradually increase the application of environmentally friendly gas-insulated metal enclosed switchgear in new construction and renovation projects, with the application volume accounting for no less than 30% of the total new additions and an annual growth rate of no less than 8%. In core load areas of large and medium-sized cities and regions with harsh equipment operating environments, the application proportion can be appropriately increased. From 2019 to 2021, the application volume of environmentally friendly gas-insulated metal enclosed switchgear in new construction and renovation projects will account for no less than 90% of the total new additions, and in core load areas of large and medium-sized cities and regions with harsh equipment operating environments, the application proportion can be appropriately increased.

Transient oscillographic fault indicator I. Technical principle and characteristics

The transient oscillograph-type fault indicator is a device installed on the distribution line, which monitors the line operating parameters, detects and indicates various types of short circuits and grounding faults, and uploads monitoring information and fault detection data to the main distribution station.

The transient oscillographic fault indicator consists of an acquisition unit and a collection unit. It synthesizes zero-sequence current by collecting three-phase fault current waveform files from the fault line, and determines the fault section based on the transient characteristics of the three-phase synthesized zero-sequence current. It accurately indicates the fault line and fault point and issues a fault alarm indication (or message). It has basic functions such as short circuit and ground fault identification, remote fault alarm, fault alarm reset, prevention of false alarms due to load fluctuations, and live loading and unloading, as well as advanced functions such as monitoring line status information, transient fault and fault judgment, and fault oscillography.

Compared to traditional fault indicators, transient oscillograph-based fault indicators can narrow down the fault diagnosis area, shorten the fault removal time, and avoid the traditional practice of repeatedly switching off the power to inspect the line and locate the fault point. This provides strong support for quickly resolving faults and restoring normal power supply.

 II. Applicable conditions

(1) Transient oscillographic fault indicators should be used for lines prone to transient faults, with grounding resistance of 1000Ω or less, and they need to be used in conjunction with the main distribution station;

(2) Applicable to three-phase AC distribution overhead lines with rated voltage ranging from 6.6kV to 35kV and rated frequency of 50Hz;

(3) Not applicable to normal low-load or no-load lines.

III. Promotion and Application Plan

From 2016 to 2018, pilot applications were conducted in some units within the company.

From 2019 to 2021, we will gradually expand its application within the company.  

Distribution automation terminal security protection technology I. Technical principles and characteristics

The security protection technology for distribution automation terminals refers to technical measures that embed a security chip in the distribution terminals to achieve information security protections such as communication link protection, dual identity authentication, data encryption, and data integrity protection between the terminals and the main station as well as on-site operation and maintenance terminals.

The distribution terminal utilizes an embedded security chip to achieve bidirectional identity authentication between the distribution terminal and the main distribution station based on a domestic asymmetric cryptographic algorithm. It conducts security authentication and data integrity verification for remote parameter settings and remote upgrade instructions originating from the main distribution station