A corona ring, also called an anti-corona ring, is a toroid of conductive material, usually metal, which is attached to a terminal of high voltage equipment. The role of the corona ring is to distribute the electric field gradient and lower its maximum values below the corona threshold, preventing corona discharge. Corona rings are used on very high voltage power transmission insulators and switchgear, and on scientific research apparatus that generates high voltages.

Corona discharge is an ionization of air adjacent to high voltage conductors. It is sometimes visible as a dim blue glow in the air next to high voltage equipment. The high electric field ionizes the air, allowing current to leak from the conductor into the air. In electric power transmission lines and equipment, corona results in an economically significant waste of power. In devices such as electrostatic generators, marx generators, and television sets, the current load caused by corona leakage can reduce the voltage produced by the device, causing it to malfunction. Coronas also produce noxious and corrosive ozone gas, which can cause aging and embrittlement of nearby structures such as insulators, and create a health hazard for workers and local residents. For these reasons corona discharge is considered undesirable in most electrical equipment.

Type		Dimension (mm)						Weight (kg)
		L	L1	D	S	H	Φ
	FJPE-50/1800/300	1800	900	18	60	300	50	9.5
	FJPE-50/1800/325	1800	900	18	60	325	50	9.5
	FJPE-50/1800/350	1800	900	18	60	350	50	9.5
	FJPE-50/1800/375	1800	900	18	60	375	50	9.5
	FJPE-50/1900/300	1900	900	18	60	300	50	9.5
	FJPE-50/1900/325	1900	900	18	60	325	50	9.5
	FJPE-50/1900/350	1900	900	18	60	350	50	9.5
	FJPE-50/1900/375	1900	900	18	60	375	50	9.5

Type		Dimension (mm)							Weight (kg)
		L	L1	H	D	Φ	a	b
	JPL-500N	1450	900	330	50	18	60	60	9.3
	FJP-500ND	1670	900	405	50	18	60	60	10.5
	FJP-500N/GH	1450	920	330	60	18	60	60	11.3
	FP-500N/GH	1450	900	330	60	18	60	60	10.7
	Note:The main body is aluminum, and the rest are hot-dip galvanized steel parts.

Type		Dimension (mm)								Weight (kg)
		L	L1	L2	H	D	Φ	C	a
	PLJ-500K	700	600	250	235	50	18	20	60	3.9
	PLJ-500X	700	600	270	235	50	18	20	60	4.4
	PPLJ-500K	700	600	270	235	50	18	20	60	4.6
	Note:The main body is aluminum, and the rest are hot-dip galvanized steel parts.

Type		Dimension (mm)							Weight (kg)
		L	L1	H	D	M	C	a
	FJP-500XDA	800	700	320	50	16	20	80	6.2
	JL-500XD	700	600	290	50	16	20	80	4.33
	FJP-500XD1L	700	600	270	50	12	20	45	4.2
	FJ-500XD/GH	700	600	290	60	12	20	80	9.85
	Note:The main body is aluminum, and the rest are hot-dip galvanized steel parts.