DC intermediate connector

Application areas:

DC intermediate joints are mainly used in flexible high-voltage direct current (HVDC) transmission. They have gained widespread attention due to their flexible operating power range, operational independence, simplicity in power direction control, and superior transmission performance.

Product Description

The integral cable joint body is injection molded from high-quality EPDM rubber and is suitable for cross-linked polyethylene insulated cables with aluminum or copper conductors. It mainly consists of a joint body and an outer shell. The outer shell comprises a thick copper shell and a robust fiberglass shell, with high-voltage cable sealant filling the spaces between them. The product offers excellent mechanical protection, reliable electrical performance, and perfect sealing.

Product Parameters

1. VSC Load Cycling Test: The load cycle includes a heating cycle and a cooling cycle; 8 hours of heating followed by 16 hours of natural cooling constitutes one cycle. During the last two hours of the heating cycle, the conductor temperature is maintained at 70°C. The DC voltage UT during heating starts from the negative polarity. One reversal coincides with the load current stop time in the 24-hour load cycle. Each cycle is applied for 12 consecutive times.

2. VSC superimposed impulse voltage test (test conducted under thermal conditions):

2.1 DC superimposed operating impulse voltage test:

Preheat and apply a positive polarity U0 voltage for at least 10 hours; under positive polarity U0, superimpose a positive polarity operating impulse voltage Up2,S for 10 consecutive times; under positive polarity U0, superimpose a positive polarity operating impulse voltage -Up2,O for 10 consecutive times.

Preheat and apply a negative polarity U0 voltage for at least 10 hours; under negative polarity -U0, superimpose a positive polarity operating impulse voltage -Up2,S for 10 consecutive times; under negative polarity -U0, superimpose a positive polarity operating impulse voltage Up2,O for 10 consecutive times.

2.2 DC superimposed lightning impulse voltage test:

Preheat and apply a positive polarity U0 voltage for at least 10 hours; then superimpose a negative polarity lightning impulse voltage -Up1 for 10 consecutive times.

Preheat and apply a negative polarity -U0 voltage for at least 10 hours; then superimpose a positive polarity lightning impulse voltage Up1 for 10 consecutive times.

2.3 Subsequent DC voltage test

Exposed to a negative polarity voltage -UT at room temperature for 2 hours.

Rated voltage		±150kV	±320kV
VSC load cycling test	UT	277.5	592
DC superposition operation impulse voltage test	U0	150	320
	Up2,S	450	700
	Up2,O	290	700
DC superimposed lightning impulse voltage test	U0	160	320
	Up1	400	480
DC voltage test	UT	277.5	592

Rated voltage	kV		±150	±320
Technical parameters
Meets standards			1. National Power Grid Conference Standard CIGRE 419 2. TICW7-2012 Test Specification for Extruded Insulated Power Cables for DC Transmission with Rated Voltage of 500kV and Below
Rated current	A		Not smaller than the connecting cable
short circuit current			Not smaller than the connecting cable
conductor connection			crimp type
Electric field control method			Geometric method
Stress cone material			EPDM
Filler glue			High-voltage cable sealant
Applicable cable cross-section	mm2		240-1600	400-2500
weight	Kg		120	160
Applicable cable shielding/sheath
Operating environment
conductor rated temperature	During normal operation	℃	90	90
	Short circuit	℃	250	250
Suitable ambient temperature range	℃		-40-60	-40-60
Laying method
Permissible seismic intensity at the terminal	Spend		8	8

Product Selection